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Computer Architecture - A Quantitative Approach (Book Excerpt)

noreply@blogger.com (Tigre de Fogo) — Wed, 07 Jan 2009 17:16:00 +0000

Computer Architecture - A Quantitative Approach (Book Excerpt) by John L. Hennessy and David A. Patterson

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I am very lucky to have studied computer architecture under Prof. David Patterson at U.C. Berkeley more than 20 years ago. I enjoyed the courses I took from him, in the early days of RISC architecture. Since leaving Berkeley to help found Sun Microsystems, I have used the ideas from his courses and many more that are described in this important book.

The good news today is that this book covers incredibly important and contemporary material. The further good news is that much exciting and challenging work remains to be done, and that working from Computer Architecture: A Quantitative Approach is a great way to start.

The most successful architectural projects that I have been involved in have always started from simple ideas, with advantages explainable using simple numerical models derived from hunches and rules of thumb. The continuing rapid advances in computing technology and new applications ensure that we will need new similarly simple models to understand what is possible in the future, and that new classes of applications will stress systems in different and interesting ways.

The quantitative approach introduced in Chapter 1 is essential to understanding these issues. In particular, we expect to see, in the near future, much more emphasis on minimizing power to meet the demands of a given application, across all sizes of systems; much remains to be learned in this area.

I have worked with many different instruction sets in my career. I first programmed a PDP-8, whose instruction set was so simple that a friend easily learned to disassemble programs just by glancing at the hole punches in paper tape! I wrote a lot of code in PDP-11 assembler, including an interpreter for the Pascal programming language and for the VAX (which was used as an example in the first edition of this book); the success of the VAX led to the widespread use of UNIX on the early Internet.

The PDP-11 and VAX were very conventional complex instruction set (CISC) computer architectures, with relatively compact instruction sets that proved nearly impossible to pipeline. For a number of years in public talks I used the performance of the VAX 11/780 as the baseline; its speed was extremely well known because faster implementations of the architecture were so long delayed. VAX performance stalled out just as the x86 and 680x0 CISC architectures were appearing in microprocessors; the strong economic advantages of microprocessors led to their overwhelming dominance. Then the simpler reduced instruction set (RISC) computer architectures—pioneered by John Cocke at IBM; promoted and named by Patterson and Hennessy; and commercialized in POWER PC, MIPS, and SPARC—were implemented as microprocessors and permitted highperformance pipeline implementations through the use of their simple registeroriented instruction sets. A downside of RISC was the larger code size of programs and resulting greater instruction fetch bandwidth, a cost that could be seen to be acceptable using the techniques of Chapter 1 and by believing in the future CMOS technology trends promoted in the now-classic views of Carver Mead. The kind of clear-thinking approach to the present problems and to the shape of future computing advances that led to RISC architecture is the focus of this book.

Chapter 2 (and various appendices) presents interesting examples of contemporary and important historical instruction set architecture. RISC architecture—the focus of so much work in the last twenty years—is by no means the final word here. I worked on the design of the SPARC architecture and several implementations for a decade, but more recently have worked on two different styles of processor: picoJava, which implemented most of the Java Virtual Machine instructions—a compact, high-level, bytecoded instruction set—and MAJC, a very simple and multithreaded VLIW for Java and media-intensive applications. These two architectures addressed different and new market needs: for lowpower chips to run embedded devices where space and power are at a premium, and for high performance for a given amount of power and cost where parallel applications are possible. While neither has achieved widespread commercial success, I expect that the future will see many opportunities for different ISAs, and an in-depth knowledge of history here often gives great guidance—the relationships between key factors, such as the program size, execution speed, and power consumption, returning to previous balances that led to great designs in the past.

Chapters 3 and 4 describe instruction-level parallelism (ILP): the ability to execute more than one instruction at a time. This has been aided greatly, in the last 20 years, by techniques such as RISC and VLIW (very long instruction word) computing. But as later chapters here point out, both RISC and especially VLIW as practiced in the Intel itanium architecture are very power intensive. In our attempts to extract more instruction-level parallelism, we are running up against the fact that the complexity of a design that attempts to execute N instructions simultaneously grows like N2: the number of transistors and number of watts to produce each result increases dramatically as we attempt to execute many instructions of arbitrary programs simultaneously. There is thus a clear countertrend emerging: using simpler pipelines with more realistic levels of ILP while exploiting other kinds of parallelism by running both multiple threads of execution per processor and, often, multiple processors on a single chip. The challenge for designers of high-performance systems of the future is to understand when simultaneous execution is possible, but then to use these techniques judiciously in combination with other, less granular techniques that are less power intensive and complex.

In graduate school I would often joke that cache memories were the only great idea in computer science. But truly, where you put things affects profoundly the design of computer systems. Chapter 5 describes the classical design of cache and main memory hierarchies and virtual memory. And now, new, higher-level programming languages like Java support much more reliable software because they insist on the use of garbage collection and array bounds checking, so that security breaches from "buffer overflow" and insidious bugs from false sharing of memory do not creep into large programs. It is only languages, such as Java, that insist on the use of automatic storage management that can implement true software components. But garbage collectors are notoriously hard on memory hierarchies, and the design of systems and language implementations to work well for such areas is an active area of research, where much good work has been done but much exciting work remains.

Java also strongly supports thread-level parallelism—a key to simple, powerefficient, and high-performance system implementations that avoids the N2 problem discussed earlier but brings challenges of its own. A good foundational understanding of these issues can be had in Chapter 6. Traditionally, each processor was a separate chip, and keeping the various processors synchronized was expensive, both because of its impact on the memory hierarchy and because the synchronization operations themselves were very expensive. The Java language is also trying to address these issues: we tried, in the Java Language Specification, which I coauthored, to write a description of the memory model implied by the language. While this description turned out to have (fixable) technical problems, it is increasingly clear that we need to think about the memory hierarchy in the design of languages that are intended to work well on the newer system platforms. We view the Java specification as a first step in much good work to be done in the future.

As Chapter 7 describes, storage has evolved from being connected to individual computers to being a separate network resource. This is reminiscent of computer graphics, where graphics processing that was previously done in a host processor often became a separate function as the importance of graphics increased. All this is likely to change radically in the coming years—massively parallel host processors are likely to be able to do graphics better than dedicated outboard graphics units, and new breakthroughs in storage technologies, such as memories made from molecular electronics and other atomic-level nanotechnologies, should greatly reduce both the cost of storage and the access time. The resulting dramatic decreases in storage cost and access time will strongly encourage the use of multiple copies of data stored on individual computing nodes, rather than shared over a network. The "wheel of reincarnation," familiar from graphics, will appear in storage.

Chapter 8 provides a great foundational description of computer interconnects and networks. My model of these comes from Andy Bechtolsheim, another of the cofounders of Sun, who famously said, "Ethernet always wins."More modestly stated: given the need for a new networking interconnect, and despite its shortcomings, adapted versions of the Ethernet protocols seem to have met with overwhelming success in the marketplace. Why? Factors such as the simplicity and familiarity of the protocols are obvious, but quite possibly the most likely reason is that the people who are adapting Ethernet can get on with the job at hand rather than arguing about details that, in the end, aren’t dispositive. This lesson can be generalized to apply to all the areas of computer architecture discussed in this book.

One of the things I remember Dave Patterson saying many years ago is that for each new project you only get so many "cleverness beans." That is, you can be very clever in a few areas of your design, but if you try to be clever in all of them, the design will probably fail to achieve its goals—or even fail to work or to be finished at all. The overriding lesson that I have learned in 20 plus years of working on these kinds of designs is that you must choose what is important and focus on that; true wisdom is to know what to leave out. A deep knowledge of what has gone before is key to this ability.

And you must also choose your assumptions carefully. Many years ago I attended a conference in Hawaii (yes, it was a boondoggle, but read on) where Maurice Wilkes, the legendary computer architect, gave a speech. What he said, paraphrased in my memory, is that good research often consists of assuming something that seems untrue or unlikely today will become true and investigating the consequences of that assumption. And if the unlikely assumption indeed then becomes true in the world, you will have done timely and sometimes, then, even great research! So, for example, the research group at Xerox PARC assumed that everyone would have access to a personal computer with a graphics display connected to others by an internetwork and the ability to print inexpensively using Xerography. How true all this became, and how seminally important their work was!

In our time, and in the field of computer architecture, I think there are a number of assumptions that will become true. Some are not controversial, such as that Moore’s Law is likely to continue for another decade or so and that the complexity of large chip designs is reaching practical limits, often beyond the point of positive returns for additional complexity. More controversially, perhaps, molecular electronics is likely to greatly reduce the cost of storage and probably logic elements as well, optical interconnects will greatly increase the bandwidth and reduce the error rates of interconnects, software will continue to be unreliable because it is so difficult, and security will continue to be important because its absence is so debilitating.

Taking advantage of the strong positive trends detailed in this book and using them to mitigate the negative ones will challenge the next generation of computer architects, to design a range of systems of many shapes and sizes.

Computer architecture design problems are becoming more varied and interesting. Now is an exciting time to be starting out or reacquainting yourself with the latest in this field, and this book is the best place to start. See you in the chips!

Computer technology has made incredible progress in the roughly 55 years since the first general-purpose electronic computer was created. Today, less than a thousand dollars will purchase a personal computer that has more performance, more main memory, and more disk storage than a computer bought in 1980 for 1 million dollars. This rapid rate of improvement has come both from advances in the technology used to build computers and from innovation in computer design.

Although technological improvements have been fairly steady, progress arising from better computer architectures has been much less consistent. During the first 25 years of electronic computers, both forces made a major contribution; but beginning in about 1970, computer designers became largely dependent upon integrated circuit technology. During the 1970s, performance continued to improve at about 25% to 30% per year for the mainframes and minicomputers that dominated the industry.

The late 1970s saw the emergence of the microprocessor. The ability of the microprocessor to ride the improvements in integrated circuit technology more closely than the less integrated mainframes and minicomputers led to a higher rate of improvement—roughly 35% growth per year in performance.

This growth rate, combined with the cost advantages of a mass-produced microprocessor, led to an increasing fraction of the computer business being based on microprocessors. In addition, two significant changes in the computer marketplace made it easier than ever before to be commercially successful with a new architecture. First, the virtual elimination of assembly language programming reduced the need for object-code compatibility. Second, the creation of standardized, vendor-independent operating systems, such as UNIX and its clone, Linux, lowered the cost and risk of bringing out a new architecture.

These changes made it possible to successfully develop a new set of architectures, called RISC (Reduced Instruction Set Computer) architectures, in the early 1980s. The RISC-based machines focused the attention of designers on two critical performance techniques, the exploitation of instruction-level parallelism (initially through pipelining and later through multiple instruction issue) and the use of caches (initially in simple forms and later using more sophisticated organizations and optimizations). The combination of architectural and organizational enhancements has led to 20 years of sustained growth in performance at an annual rate of over 50%.

The effect of this dramatic growth rate has been twofold. First, it has signifi- cantly enhanced the capability available to computer users. For many applications, the highest-performance microprocessors of today outperform the supercomputer of less than 10 years ago.

Second, this dramatic rate of improvement has led to the dominance of microprocessor-based computers across the entire range of the computer design. Workstations and PCs have emerged as major products in the computer industry. Minicomputers, which were traditionally made from off-the-shelf logic or from gate arrays, have been replaced by servers made using microprocessors. Mainframes have been almost completely replaced with multiprocessors consisting of small numbers of off-the-shelf microprocessors. Even high-end supercomputers are being built with collections of microprocessors.

Freedom from compatibility with old designs and the use of microprocessor technology led to a renaissance in computer design, which emphasized both architectural innovation and efficient use of technology improvements. This renaissance is responsible for the higher performance growth, a rate that is unprecedented in the computer industry. This rate of growth has compounded so that by 2001, the difference between the highestperformance microprocessors and what would have been obtained by relying solely on technology, including improved circuit design, was about a factor of 15.

Figure 1.1 Growth in microprocessor performance since the mid-1980s has been substantially higher than in earlier years as shown by plotting SPECint performance. This chart plots relative performance as measured by the SPECint benchmarks with base of one being a VAX 11/780. Since SPEC has changed over the years, performance of newer machines is estimated by a scaling factor that relates the performance for two different versions of SPEC (e.g., SPEC92 and SPEC95). Prior to the mid-1980s, microprocessor performance growth was largely technology driven and averaged about 35% per year. The increase in growth since then is attributable to more advanced architectural and organizational ideas. By 2001 this growth led to a difference in performance of about a factor of 15. Performance for floating-point-oriented calculations has increased even faster.

In the last few years, the tremendous improvement in integrated circuit capability has allowed older, less-streamlined architectures, such as the x86 (or IA-32) architecture, to adopt many of the innovations first pioneered in the RISC designs. As we will see, modern x86 processors basically consist of a front end that fetches and decodes x86 instructions and maps them into simple ALU, memory access, or branch operations that can be executed on a RISC-style pipelined processor. Beginning in the late 1990s, as transistor counts soared, the overhead (in transistors) of interpreting the more complex x86 architecture became negligible as a percentage of the total transistor count of a modern microprocessor.

This text is about the architectural ideas and accompanying compiler improvements that have made this incredible growth rate possible. At the center of this dramatic revolution has been the development of a quantitative approach to computer design and analysis that uses empirical observations of programs, experimentation, and simulation as its tools. It is this style and approach to computer design that is reflected in this text.

Sustaining the recent improvements in cost and performance will require continuing innovations in computer design, and we believe such innovations will be founded on this quantitative approach to computer design. Hence, this book has been written not only to document this design style, but also to stimulate you to contribute to this progress.

Chapter 5 - I/O And Consistency of Cached Data

Because of caches, data can be found in memory and in the cache. As long as the CPU is the sole device changing or reading the data and the cache stands between the CPU and memory, there is little danger in the CPU seeing the old or stale copy. I/O devices give the opportunity for other devices to cause copies to be inconsistent or for other devices to read the stale copies. Figure 5.46 illustrates the problem, generally referred to as the cache-coherency problem.

The question is this: Where does the I/O occur in the computer-between the I/O device and the cache or between the I/O device and main memory? If input puts data into the cache and output reads data from the cache, both I/O and the CPU see the same data, and the problem is solved. The difficulty in this approach is that it interferes with the CPU. I/O competing with the CPU for cache access will cause the CPU to stall for I/O. Input will also interfere with the cache by displacing some information with the new data that is unlikely to be accessed by the CPU soon. For example, on a page fault the CPU may need to access a few words in a page, but a program is not likely to access every word of the page if it were loaded into the cache. Given the integration of caches onto the same integrated circuit, it is also difficult for that interface to be visible.

The goal for the I/O system in a computer with a cache is to prevent the stale data problem while interfering with the CPU as little as possible. Many systems, therefore, prefer that I/O occur directly to main memory, with main memory

FIGURE 5.46 The cache-coherency problem. A' and B refer to the cached copiesof A and B in memory. (a) shows cache and main memory in a coherent state. In (b) we assume a write-back cache when the CPU writes 550 into A. Now A' has the value but the value in memory has the old, stale value of 100. If an output used the value of A from memory, it would get the stale data. In (c) the I/O system inputs 440 into the memory copy of B, so now B, in the cache has the old, stale data acting as an I/O buffer. If a write-through cache is used, then memory has an upto-date copy of the information, and there is no stale-data issue for output. (This is a reason many machines use write through.) Input requires some extra work. The software solution is to guarantee that no blocks of the I/O buffer designated for input are in the cache. In one approach, a buffer page is marked as noncachable; the operating system always inputs to such a page. In another approach, the operating system flushes the buffer addresses from the cache after the input occurs. A hardware solution is to check the I/O addresses on input to see if they are in the cache; to avoid slowing down the cache to check addresses, sometimes a duplicate set of tags are used to allow checking of I/O addresses in parallel with processor cache accesses. If there is a match of I/O addresses in the cache, the cache entries are invalidated to avoid stale data. All these approaches can also be used for output with write-back caches. More about this is found in Chapter 6.

The cache-coherency problem applies to multiprocessors as well as I/O. Unlike I/O, where multiple data copies are a rare event-one to be avoided whenever possible-a program running on multiple processors will want to have copies of the same data in several caches. Performance of a multiprocessor program depends on the performance of the system when sharing data. The protocols to maintain coherency for multiple processors are called cache-coherency protocols and are described in Chapter 8.

5.10 Putting It All Together the Alpha AXP 21064 Memory Hierarchy

Thus far we have given glimpses of the Alpha AXP 21064 memory hierarchy; this section unveils the full design and shows the performance of its components for the SPEC92 programs. Figure 5.47 gives the overall picture of this design.

Let's really start at the beginning, when the Alpha is turned on. Hardware on the chip loads the instruction cache from an external PROM. This initialization allows the 8-KB instruction cache to omit a valid bit, for there are always valid instructions in the cache; they just might not be the ones your program is interested in. The hardware does clear the valid bits in the data cache. The PC is set to the kseg segment so that the instruction addresses are not translated, thereby avoiding the TLB.

One of the first steps is to update the instruction TLB with valid page table entries (PTEs) for this process. Kernel code updates the TLB with the contents of the appropriate page table entry for each page to be mapped. The instruction TLB has eight entries for 8-KB pages and four for 4-MB pages. (The 4-MB pages are used by large programs such as the operating system or data bases that will likely touch most of their code.) A miss in the TLB invokes the Privileged Architecture Library (PAL code) software that updates the TLB. PAL code is simply machine language routines with some implementation-specific extensions to allow access to low-level hardware, such as the TLB. PAL code runs with exceptions disabled, and instruction accesses are not checked for memory management violations, allowing PAL code to fill the TLB.

Once the operating system is ready to begin executing a user process, it sets the PC to the appropriate address in segment segO. We are now ready to follow memory hierarchy in action: Figure 5.47 is labeled with the steps of this narrative. The page frame portion of this address is sent to the TLB (step 1), while the 8-bit index from the page offset is sent to the direct-mapped 8-KB (256 32-byte blocks) instruction cache (step 2). The fully associative TLB simultaneously searches all 12 entries to find a match between the address and a valid PTE (step 3). In addition to translating the address, the TLB checks to see if the PTE demands that this access result in an exception. An exception might occur if either this access violates the protection on the page or ifthe page is not in main memory. If there is no exception, and if the translated physical address matches the tag in the instruction cache (step 4), then the proper 8 bytes of the 32-byte block are furnished to the CPU using the lower bits of the page offset (step 5), and the instruction stream access is done.

A miss, on the other hand, simultaneously starts an access to the second-level cache (step 6) and checks the prefetch instruction stream buffer (step 7). If the desired instruction is found in the stream buffer (step 8), the critical 8 bytes are sent to the CPU, the full 32-byte block of the stream buffer is written into the instruction cache (step 9), and the request to the second-level cache is canceled. Steps 6 to 9 take just a single clock cycle.

If the instruction is not in the prefetch stream buffer, the second-level cache continues trying to fetch the block. The 21064 microprocessor is designed to work with direct-mapped second-level caches from 128 KB to 8 MB with a miss penalty between 3 and 16 clock cycles. For this section we use the memory system of the DEC 3000 model 800 Alpha AXP. It has a 2-MB (65,536 32-byte blocks) second-level cache, so the 29-bit block address is divided into a 13-bit tag and a 16-bit index (step 10). The cache reads the tag from that index and if it matches (step 11), the cache returns the critical 16 bytes in the first 5 clock cycles and the other 16 bytes in the next 5 clock cycles (step 12). The path between the first- and second-level cache is 128 bits wide (16 bytes). At the same time, a request is made for the next sequential 32-byte block, which is loaded into the instruction stream buffer in the next 10 clock cycles (step 13).

The instruction stream does not rely on the TLB for address translation. It simply increments the physical address of the miss by 32 bytes, checking to make sure that the new address is within the same page. If the incremented address crosses a page boundary, then the prefetch is suppressed.

If the instruction is not found in the secondary cache, the translated physical address is sent to memory (step 14). The DEC 3000 model 800 divides memory into four memory mother boards (MMB), each of which contains two to eight SIMMs (single inline memory modules). The SIMMs come with eight DRAMs for information plus two DRAMs for error protection per side, and the options are single- or double-sided SIMMs using I-Mbit, 4-Mbit, or 16-Mbit DRAMs. Hence the memory capacity of the model 800 is 8 MB (4 x 2 x 8 x I x 1/8) to 1024 MB (4 x 8 x 8 x 16 x 2/8), always organized 256 bits wide. The average time to transfer 32 bytes from memory to the secondary cache is 36 clock cycles after the processor makes the request. The second-level cache loads this data 16 bytes at a time.

Since the second-level cache is a write-back cache, any miss can lead to the old block being written back to memory. The 21064 places this "victim" block into a victim buffer to get out of the way of new data (step 15). The new data are loaded into the cache as soon as they arrive (step 16), and then the old data are written from the victim buffer (step 17). There is a single block in the victim buffer, so a second miss would need to stall until the victim buffer empties.

Suppose this initial instruction is a load. It will send the page frame of its data address to the data TLB (step 18) at the same time as the 8-bit index from the page offset is sent to the data cache (step 19). The data TLB is a fully associative cache containing 32 PTEs, each of which represents page sizes from 8 KB to 4 MB. A TLB miss will trap to PAL code to load the valid PTE for this address. In the worst case, the page is not in memory, and the operating system gets the page from disk (step 20). Since millions of instructions could execute during a page fault, the operating system will swap in another process if there is something waiting to run.

Assuming that we have a valid PTE in the data TLB (step 21), the cache tag and the physical page frame are compared (step 22), with a match sending the desired 8 bytes from the 32-byte block to the CPU (step 23). A miss goes to the second-level cache, which proceeds exactly like an instruction miss.

Suppose the instruction is a store instead of a load. The page frame portion of the data address is again sent to the data TLB and the data cache (steps 18 and 19), which checks for protection violations as well as translates the address. The physical address is then sent to the data cache (steps 21 and 22). Since the data cache uses write through, the store data are simultaneously sent to the write buffer (step 24) and the data cache (step 25). As explained on page 425, the 21064 pipelines write hits. The data address of this store is checked for a match, and at the same time the data from the previous write hit are written to the cache (step 26). If the address check was a hit, then the data from this store are placed in the write pipeline buffer. On a miss, the data are just sent to the write buffer since the data cache does not allocate on a write miss.

The write buffer takes over now. It has four entries, each containing a whole cache block. If the buffer is full, then the CPU must stall until a block is written to the second-level cache. If the buffer is not full, the CPU continues and the address of the word is presented to the write buffer (step 27). It checks to see if the word matches any block already in the buffer so that a sequence of writes can be stitched together into a full block, thereby optimizing use of the write bandwidth between the first- and second-level cache.

All writes are eventually passed on to the second-level cache. If a write is a hit, then the data are written to the cache (step 28). Since the second-level cache uses write back, it cannot pipeline writes: a full 32-byte block write takes 5 clock cycles to check the address and 10 clock cycles to write the data. A write of 16 bytes or less takes 5 clock cycles to check the address and 5 clock cycles to write the data. In either case the cache marks the block as dirty.

If the access to the second-level cache is a miss, the victim block is checked to see if it is dirty; if so, it is placed in the victim buffer as before (step 15). If the new data are a full block, then the data are simply written and marked dirty. A partial block write results in an access to main memory since the second-level cache policy is to allocate on a write miss...

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MySQL Developer's Library (Book Excerpt) by Paul DuBois

noreply@blogger.com (Tigre de Fogo) — Tue, 23 Dec 2008 15:01:00 +0000

MySQL Developer's Library (Book Excerpt) by Paul DuBois

Book price (Amazon.com)

Introduction to MySQL and SQL: This chapter provides an introduction to the MySQL relational database management system (RDBMS), and to the Structured Query Language (SQL) that MySQL understands. It lays out basic terms and concepts you should understand, describes the sample database we'll be using for examples throughout the book, and provides a tutorial that shows you how to use MySQL to create a database and interact with it.

Begin here if you are new to databases and perhaps uncertain whether or not you need one or can use one.You should also read the chapter if you don't know anything about MySQL or SQL and need an introductory guide to get started. Readers who have experience with MySQL or with database systems might want to skim through the material. However, everybody should read the section "A Sample Database" because it's best if you're familiar with the purpose and contents of the database that we'll be using repeatedly throughout the book.

How MySQL Can Help You: This section describes situations in which the MySQL database system is useful. This will give you an idea of the kinds of things MySQL can do and the ways in which it can help you. If you don't need to be convinced about the usefulness of a database system-perhaps because you've already got a problem in mind and just want to find out how to put MySQL to work helping you solve it-you can proceed to "A Sample Database."

A database system is essentially just a way to manage lists of information. The information can come from a variety of sources. For example, it can represent research data, business records, customer requests, sports statistics, sales reports, personal hobby information, personnel records, bug reports, or student grades. However, although database systems can deal with a wide range of information, you don't use such a system for its own sake. If a job is easy to do already, there's no reason to drag a database into it just to use one. A grocery list is a good example:You write down the items to get, cross them off as you do your shopping, and then throw the list away. It's highly unlikely that you'd use a database for this. Even if you have a palmtop computer, you'd probably use its notepad function for a grocery list, not its database capabilities.

The power of a database system comes in when the information you want to organize and manage becomes voluminous or complex so that your records become more burdensome than you care to deal with by hand. Databases can be used by large corporations processing millions of transactions a day, of course. But even small-scale operations involving a single person maintaining information of personal interest may require a database. It's not difficult to think of situations in which the use of a database can be beneficial because you needn't have huge amounts of information before that information becomes difficult to manage. Consider the following situations:

Your carpentry business has several employees.You need to maintain employee and payroll records so that you know who you've paid and when, and you must summarize those records so that you can report earnings statements to the government for tax purposes. You also need to keep track of the jobs your company has been hired to do and which employees you've scheduled to work on each job.

You run a network of automobile parts warehouses and need to be able to tell which ones have any given part in their inventory so that you can fill customer orders.

As a toy seller, you're particularly subject to fad-dependent demand for items that you carry.You want to know what the current sales trajectory is for certain items so that you can estimate whether to increase inventory (for an item that's becoming more popular) or decrease it (so you're not stuck with a lot of stock for something that's no longer selling well).

That pile of research data you've been collecting over the course of many years needs to be analyzed for publication, lest the dictum "publish or perish" become the epitaph for your career.You want to boil down large amounts of raw data to generate summary information, and to pull out selected subsets of observations for more detailed statistical analysis.

You're a popular speaker who travels the country to many types of assemblies, such as graduations, business meetings, civic organizations, and political conventions.You give so many addresses that it's difficult to remember what you've spoken on at each place you've been, so you'd like to maintain records of your past talks and use them to help you plan future engagements. If you return to a place at which you've spoken before, you don't want to give a talk similar to one you've already delivered there, and a record of each place you've been would help you avoid repeats.You'd also like to note how wen your talks are received. (Your address "Why I Love Cats" to the Metropolitan Kennel Club was something of a dud, and you don't want to make that mistake again the next time you're there.)

You're a teacher who needs to keep track of grades and attendance. Each time you give a quiz or a test, you record every student's grade. It's easy enough to write down scores in a gradebook, but using the scores later is a tedious chore. You'd rather avoid sorting the scores for each test to determine the grading curve, and you'd really rather not add up each student's scores when you determine final grades at the end of the grading period. Counting each student's absences is no fun, either.

The organization for which you are the secretary maintains a directory of members. (The organization could be anything-a professional society, a club, a repertory company, a symphony orchestra, or an athletic booster club.) You generate the directory in printed form each year for members, based on a word processor document that you edit as membership information changes.

You're tired of maintaining the directory that way because it limits what you can do with it. It's difficult to sort the entries in different ways, and you can't easily select just certain parts of each entry (such as a list consisting only of names and phone numbers). Nor can you easily find a subset of members, such as those who need to renew their memberships soon-if you could, it would eliminate the job of looking through the entries each month to find those members who need to be sent renewal notices.

Also, you'd really like to avoid doing all the directory editing yourself, but the society doesn't have much of a budget, and hiring someone is out of the question.You've heard about the "paperless office" that's supposed to result from electronic record-keeping, but you haven't seen any benefit from it. The membership records are electronic, but, ironically, aren't in a form that can be used easily for anything except generating paper by printing the directory!

These scenarios range from situations involving large amounts to relatively small amounts of information. They share the common characteristic of involving tasks that can be performed manually but that could be performed more efficiently by a database system.

What specific benefits should you expect to see from using a database system such as MySQL?

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The Huffington Post Complete Guide to Blogging (Book Excerpt)

noreply@blogger.com (Tigre de Fogo) — Mon, 15 Dec 2008 19:02:00 +0000

The Huffington Post Complete Guide to Blogging (Book Excerpt) - The editors of the Huffington Post and Arianna Huffington

Book price (Amazon.com)

What Is a Blog? A blog at its most fundamental level is simply a "web log." That is, a regularly updated account of events or ideas posted on the web.

But calling blogs mere updated web diaries is a bit like calling poetry a pleasant arrangement of words on a page. There is an art to this. Those of us who work at HuffPost believe we are fortunate enough to be present at the advent of a new form of human communication — one that is more interactive, more democratic, and just more fun than what has come before.

Blogs can bring down a Senate majority leader. They can show what a presidential candidate talks about in unguarded moments. They can provide stay-at-home parents with a little space to rant about the tragedy of colic (or maybe share updates on a local environmental issue — and Brad Pitt — during naps). They cut out the gatekeepers of information and shorten the news cycle. They give companies new ways to communicate with customers and shareholders — and give customers and shareholders new ways to make their voices heard. Blogging gives you a feeling of satisfaction that writing a letter to the editor, or a letter to the "customer care" department of a corporation, cannot match. The public nature of blogs means that any of the billion people on this planet who own or have access to a computer can read what any of the rest of us is saying. That's true even if what we're saying is about a niche (for instance, issues germane to the mini off-road buggy community) that in the past would have gotten us labeled as freaks. In fact, because the potential audience is so huge, there is space for just about every topic you can imagine.

It is this mix of the high and low, the personal and the political, that makes blogs so fascinating and so important in an open society. When we launched HuffPost in 2005, we knew we liked blogs, but even we underestimated how head over heels we'd fall. "Blogging is definitely the most interesting thing I've done as a writer, and I've been writing full-time since the late seventies," Carol Felsenthal, author of Clinton in Exile: A President Out of the White House and a HuffPost blogger, tells us. "I used to walk my dog, Henry, first thing in the morning. Now I'm often at my computer writing a post while Henry looks at me and wonders what happened to the good old days when his owner was compulsive but not hyper-compulsive."

It's the informality and the immediacy that make blogging addictive for many of us. No editor stands between us and the public. This leads to a lot of rumors and other fluff going up on the web. But it's also enormously liberating. You can put all kinds of ideas out there. "My thoughts don't all have to be fully baked," says Marci Alboher, who writes the "Shifting Careers" column and blog for The New York Times. She posts an idea and sees what her readers think. "They help me solve the problem and let me know if I'm going down the right path. It helps me figure out what the issues are very quickly."

It is this multidirectional conversation — giving all of us a platform, expanding the scope of news, and making it a shared enterprise between producers and consumers — that makes blogs so revolutionary. We have a lot of fun blogging. We're writing this book because we're pretty sure you will too.

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The Best Ways to Secure Your Business Information

noreply@blogger.com (Tigre de Fogo) — Thu, 04 Dec 2008 00:52:00 +0000

The Best Ways to Secure Your Business Information

Effective data security starts with assessing what information you have and identifying who has access to it. Understanding how personal information moves into, through, and out of your business and who has—or could have—access is essential to assessing security vulnerabilities. You can determine the best ways to secure the information only after you’ve traced how it flows.

Inventory all computers, laptops, flash drives, disks, home computers, and other equipment to find out where your company stores sensitive data. Also inventory the information you have by type and location. Your file cabinets and computer systems are a start, but remember: your business receives personal information in a number of ways—through Web sites, from contractors, from call centers, and the like. What about information saved on laptops, employees’ home computers, flash drives, and cell phones? No inventory is complete until you check everywhere sensitive data might be stored.

Track personal information through your business by talking with your sales department, information technology staff, human resources office, accounting personnel, and outside service providers. Get a complete picture of:

Who sends sensitive personal information to your business. Do you get it from customers? Credit card companies? Banks or other financial institutions? Credit bureaus? Other businesses?

How your business receives personal information. Does it come to your business through a Web site? By e-mail? Through the mail? Is it transmitted through cash registers in stores?

What kind of information you collect at each entry point. Do you get credit card information online? Does your accounting department keep information about customers’ checking accounts?

Where you keep the information you collect at each entry point. Is it in a central computer database? On individual laptops? On disks or tapes? In file cabinets? In branch offices? Do employees have files at home?

Who has—or could have—access to the information. Which of your employees has permission to access the information? Could anyone else get a hold of it? What about vendors who supply and update software you use to process credit card transactions? Contractors operating your call center?

Different types of information present varying risks. Pay particular attention to how you keep personally identifying information: Social Security numbers, credit card or financial information, and other sensitive data. That’s what thieves use most often to commit fraud or identity theft.

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Commercial Web Hosting and P2P Bandwidth

noreply@blogger.com (Tigre de Fogo) — Mon, 24 Nov 2008 15:27:00 +0000

Commercial Web Hosting and P2P Bandwidth

In the commercial web hosting, since the hosting corporation usually owns all the servers that host the content and the network links between them, the bandwidth required to duplicate the web content and the storage overhead needed to hold the webpages are usually not the primary concerns. This is also true for certain restrictive web hosting applications, such as YouServ, which is a solution to share files and web pages of individual users through standard web protocols on the intranet of a corporation. Existing research on distributive web hosting usually focuses on improving the response time of the server, such as the server placement strategy and direction of the web request to the proper server.

However, this is not the case with a consumer P2P network, where both the network bandwidth and the storage capacity is at a premium for the peers, and the P2P web hosting application is competing with other applications for such resources. Therefore, it is necessary to develop technologies that may improve the webhosting reliability and serving bandwidth while reducing the network bandwidth used to host the web site.

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iBrain - Gary Small and Gigi Vorgan (Book Excerpt)

noreply@blogger.com (Tigre de Fogo) — Mon, 17 Nov 2008 00:43:00 +0000

iBrain - Gary Small and Gigi Vorgan (Book Excerpt)

Book price (Amazon)

The people who are crazy enough to think they can change the world are the ones who do. - Steve Jobs, CEO of Apple

You're on a plane packed with other business people, reading your electronic version of the Wall Street Journal on your laptop while downloading files to your BlackBerry and organizing your PowerPoint presentation for your first meeting when you reach New York. You relish the perfect symmetry of your schedule, to-do lists, and phone book as you notice a woman in the next row entering little written notes into her leather-bound daily planner book. You remember having one of those . . . What? Like a zillion years ago? Hey lady! Wake up and smell the computer age.

You're outside the airport now, waiting impatiently for a cab along with a hundred other people. It's finally your turn, and as you reach for the taxi door a large man pushes in front of you, practically knocking you over. Your briefcase goes flying, and your laptop and BlackBerry splatter into pieces on the pavement. As you frantically gather up the remnants of your once perfectly scheduled life, the woman with the daily planner book gracefully steps into a cab and glides away.

The current explosion of digital technology not only is changing the way we live and communicate but is rapidly and profoundly altering our brains. Daily exposure to high technology—computers, smart phones, video games, search engines like Google and Yahoo—stimulates brain cell alteration and neurotransmitter release, gradually strengthening new neuralpathways in our brains while weakening old ones. Because of the current technological revolution, our brains are evolving right now—at a speed like never before.

Besides influencing how we think, digital technology is altering how we feel, how we behave, and the way in which our brains function. Although we are unaware of these changes in our neural circuitry or brain wiring, these alterations can become permanent with repetition. This evolutionary brain process has rapidly emerged over a single generation and may represent one of the most unexpected yet pivotal advances in human history. Perhaps not since Early Man first discovered how to use a tool has the human brain been affected so quickly and so dramatically.

Television had a fundamental impact on our lives in the past century, and today the average person's brain continues to have extensive daily exposure to TV. Scientists at the University of California, Berkeley, recently found that on average Americans spend nearly three hours each day watching television or movies, or much more time spent than on all leisure physical activities combined. But in the current digital environment, the Internet is replacing television as the prime source of brain stimulation. Seven out of ten American homes are wired for high-speed Internet. We rely on the Internet and digital technology for entertainment, political discussion, and even social reform as well as communication with friends and co-workers.

As the brain evolves and shifts its focus toward new technological skills, it drifts away from fundamental social skills, such as reading facial expressions during conversation or grasping the emotional context of a subtle gesture. A Stanford University study found that for every hour we spend on our computers, traditional face-to-face interaction time with other people drops by nearly thirty minutes. With the weakening of the brain's neural circuitry controlling human contact, our social interactions may become awkward, and we tend to misinterpret, and even miss subtle, nonverbal messages. Imagine how the continued slipping of social skills might affect an international summit meeting ten years from now when a misread facial cue or a misunderstood gesture could make the difference between escalating military conflict or peace.

The high-tech revolution is redefining not only how we communicate but how we reach and influence people, exert political and social change, and even glimpse into the private lives of co-workers, neighbors, celebrities, and politicians. An unknown innovator can become an overnight media magnet as news of his discovery speeds across the Internet. A cell phone video camera can capture a momentary misstep of a public figure, and in minutes it becomes the most downloaded video on YouTube. Internet social networks like MySpace and Facebook have exceeded a hundred million users, emerging as the new marketing giants of the digital age and dwarfing traditional outlets such as newspapers and magazines.

Young minds tend to be the most exposed, as well as the most sensitive, to the impact of digital technology. Today's young people in their teens and twenties, who have been dubbed Digital Natives, have never known a world without computers, twenty-four-hour TV news, Internet, and cell phones—with their video, music, cameras, and text messaging. Many of these Natives rarely enter a library, let alone look something up in a traditional encyclopedia; they use Google, Yahoo, and other online search engines. The neural networks in the brains of these Digital Natives differ dramatically from those of Digital Immigrants: people—including all baby boomers—who came to the digital/computer age as adults but whose basic brain wiring was laid down during a time when direct social interaction was the norm. The extent of their early technological communication and entertainment involved the radio, telephone, and TV.

As a consequence of this overwhelming and early high-tech stimulation of the Digital Native's brain, we are witnessing the beginning of a deeply divided brain gap between younger and older minds—in just one generation. What used to be simply a generation gap that separated young people's values, music, and habits from those of their parents has now become a huge divide resulting in two separate cultures. The brains of the younger generation are digitally hardwired from toddlerhood, often at the expense of neural circuitry that controls one-on-one people skills. Individuals of the older generation face a world in which their brains must adapt to high technology, or they'll be left behind— politically, socially, and economically.

Young people have created their own digital social networks, including a shorthand type of language for text messaging, and studies show that fewer young adults read books for pleasure now than in any generation before them. Since 1982, literary reading has declined by 28 percent in eighteen- to thirty-four-year-olds. Professor Thomas Patterson and colleagues at Harvard University reported that only 16 percent of adults age eighteen to thirty read a daily newspaper, compared with 35 percent of those thirty-six and older. Patterson predicts that the future of news will be in the electronic digital media rather than the traditional print or television forms.

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Things You Should Know About Shared Hosting

noreply@blogger.com (Tigre de Fogo) — Wed, 05 Nov 2008 21:45:00 +0000

Things You Should Know About Shared Hosting
by Daren Albom

People who are building a website will always come to a point where he or she needs to get a web hosting service to host the website. Confusions strike in when they find out there are different type of hosting including shared hosting, dedicated hosting and reseller hosting. People confuse wondering which type of hosting should they go with. This article will tell you more about shared hosting and its specialty in order to give you a better idea in your decision making.

For your information, shared hosting like what the name speaks is shared among subscribers. For example when two people sign up for a shared hosting, they will host in the same physical server sharing the same IP address however their accounts are separated using software. Each of them will not be able to access the other account. So it looks like the account is independent. The service providers have kind of partitioned the storage space into two slots for two different accounts. Same theory applies when the same server has 1,000 subscribers.

You will wonder how the computer identify the correct website when internet users want to access the website hosted in shared hosting since there is only one IP address. When a user requests a website by typing the web address in to browser, it will send the request to the server through IP address and the catch is hostname of the website will be sent together as part of the request too. Therefore with IP address and the hostname the browser can determine which website you want to access. Shared hosting definitely has its strength and weakness.

Strength: shared hosting has very strong stand in pricing. As many people are sharing the same physical server the cost has been distributed evenly. The monthly subscription fee can be as low as $4.95/month and this price is easily available everywhere. This definitely fulfills the cost effectiveness of a website. Although shared hosting is cheaper than other type of hosting that does not mean it has low quality. Instead it is an ideal hosting for many webmasters. They build websites on shared hosting to run their business. Of cause the quality still rely on the proper management of hosting providers. As discussed in most of the articles, the reputation of a hosting provider is very important in this case. Thus I always go with big hosting companies like Hostgator, Lunarpages and Bluehost. Their organized management is powerful enough to maintain the quality of their shared hosting.

Weaknesses: users share the server among themselves. Sharing is still sharing. When there is irresponsible user in the sharing group, the way the fellow uses the hosting will jeopardize other accounts too. For example if a website that has very big traffic volume is hosted, the access of other website in the same server might be affected because that particular website has drawn most of the resources of the server. Although you do not know which website or account that is causing the problem, the negative effect is still visible. Therefore in this case a good hosting company will kick in and warn the users on the usage. Shared hosting has no dedicated IP for your website too. Therefore if the Domain Name Server is down (your domain name is not functional due to whatever reasons) you will not be able to access your website using just IP address like http://127.0.0.1 because the server will confused not knowing which website to show up. Also it is not possible to have dedicated SSL to your website because SSL works on IP. Since your IP is shared, the same SSL scripting will be shared among other subscribers too. However SSL sharing does not mean it will degrade the security of SSL but instead you have less control on the script.

Despite the weaknesses of shared hosting, it remains the most common hosting among webmasters. I believe this is mostly because the economic price of shared hosting. It makes web hosting affordable and is able to host decent websites. In fact shared hosting has not much difference from a dedicated hosting (dedicated hosting uses dedicated server to host your website with dedicated IP) except for the dedicated IP, dedicated server and an expensive price (could be $100+/month). So in order to host a website or a blog or even a business website, if you are not targeting a website as big as Wikipedia or YouTube, shared hosting is recommended.

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Web Site Design: Six Simple Rules

noreply@blogger.com (Tigre de Fogo) — Thu, 30 Oct 2008 23:17:00 +0000

Web Site Design: Six Simple Rules
by Pat Turman

When designing a web site you sometimes only have one chance to keep the internet visitor from clicking the back button on their web browser. Whether you are selling a product or offering a service, remember your web site design represents your business.

For years, we have been told that when going to an interview you have ten seconds to make a lasting first impression. There is no difference when designing your web site than making the first impression in an interview. You are making a first impression with the internet visitor who has searched for what you are offering in your web site design every time. The first impression can make the difference between in a paying customer or just a visitor to your web site.

Here are just five simple rules to keep in mind when designing your web site:

1) Limit the use or do not use flashy banners and advertisements at the beginning of you web site. There is a time and place for the banners and advertisement.

There is nothing more annoying then clicking on a web site to see cartoon characters, advertisements for other products flashing in front of your face. This can be too much for your potential customer. Your customer is there for a purpose and if the blatant advertisements or flashing banners turn them off they may just hit the back button before they find what they are looking for.

The only exception to this rule is determined by the purpose of you web site.

2) Make sure your web site design make it easy for the visitor to find the navigation buttons. If a customer has to search for a navigation button to find information about the company or the navigation buttons are not working, the visitor may get frustrated and leave you web site.

A rule of thumb for your navigation buttons are on the left side of your web page because the majority of people read from left to right. Think about reading a newspaper or a book. You look at the headlines then you read from the left to the right.

3) When visitors are browsing your site, have a clear indication for the visitor of where they are on your web site and how to get to other parts.

You may want to put a link on each page that the visitor clicks to take them to the home page or another page relating to the information currently viewing. In other words do not confuse your visitor or you visitor may just click off the web site totally.

4) When designing your web site pay close attention to loading time. The time it takes your web pages to load. You can reduce loading time by reducing graphics on each page. A good web site design should load under twenty seconds.

The longer it takes the pages to load the more frustrating it can be to the internet visitor. People want it yesterday not today and definitely not tomorrow.

5) Use a font that is common to all web browsers and easy to read. You have to think of your market. If you are selling a product or service that is used by older individuals you may want to increase the font.

Most of us are not going to get younger and with age, we find our eye sights are not what they use to be.

In addition, different web browsers display fonts differently. Therefore, you want to use a universal font compatible to the popular web browser for better viewing.

6) Make sure the information on your web site is up to date, and relevant to what you are offering. If your web site is selling 32", LCD Flat Screen TV's you should not be offering products to repair your driveway. I know that is extreme but people want to know they are visiting a web site that has up to date information and is relevant to what they are searching for.

These are just a few rules of web site design. There are many other things to adhere to when designing your web site for optimal visitors.

When designing your web site look at it from the customers or internet visitors standpoint. Would you want to visit this web site? Would you want to purchase a product from this web site? If you answer "no" then correct the problems.

If you deal with customer service, you need to do as they do. Get out from behind the counter and see what the customers see from where they stand. If you go "ugh", that is not good and you need to make some changes.

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Intel Entry Storage System SS4200-E

noreply@blogger.com (Tigre de Fogo) — Thu, 23 Oct 2008 03:48:00 +0000

Intel Entry Storage System SS4200-E

The Intel Entry Storage System SS4200-E is a complete yet flexible hardware and software NAS solution that instantly adds storage capacity to small business, and the small office and home office. Powered by software from EMC, the worldwide leader in information management, the Intel Entry Storage System SS4200-E offers an intuitive user interface and easy 4-step setup process. Out-of-the-box RAID and Retrospect backup software together deliver the necessary security to protect irreplaceable digital data such as accounting records, financial data, customer information, email, sales records, product info, databases—everything a small business relies on to keep their business running. With four USB 2.0 ports and two SATA ports, the Intel Entry Storage System SS4200-E can be connected to most digital devices as well as additional storage devices to form the core of a shared, centralized data access system.

Warranty: 3 years

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Intel Storage Server SSR212MC2

noreply@blogger.com (Tigre de Fogo) — Sat, 11 Oct 2008 02:02:00 +0000

Intel Storage Server SSR212MC2

The Intel Storage Server SSR212MC2 is a flexible hardware platform that can be coupled with one of a number of different industry software solutions to create an application server with internal storage (DAS) or used as a dedicated network storage appliance (NAS or SAN). Built to support Intel dual-core and quad-core CPU technologies, the SSR212MC2 offers performance and flexibility. The SSR212MC2 is a 2U rackmount storage server that supports 12 enterprise-class Serial Attached SCSI (SAS) or high-capacity Serial ATA (SATA) HDDs. This PCI Express-based platform supports up to 32 GB of fully buffered DIMMs and up to two high-performance dual-core or quad-core Intel Xeon processors. Flexible network connectivity will include quad port Gb Ethernet, 10 Gb Ethernet, Fibre Channel, or Infiniband via add-in cards.

Businesses today are being inundated with digital data, from the growth in existing applications like e-mail and databases to emerging rich-media applications such as digital video. New government regulatory requirements, corporate business continuity, and corporate disaster recovery plans are adding to the explosive growth of storage needs. All of these factors contribute to an ever-increasing need for storage in small and medium business as well as larger enterprises. The Intel Storage Server SSR212MC2 addresses this growing storage demand by supporting up to 12 enterprise-class SAS or high-capacity SATA hard drives. It features hardware support for RAID levels 0, 1, 5,10, and 50, making data more reliable and faster to access.

The Intel Storage Server SSR212MC2 features support for high-capacity, 7,200 RPM SATA hard disk drives (HDD), which are less expensive than Fibre Channel or SCSI drives and simplify cabling. Additionally, SATA drives offer software transparency and scalability to help lower upgrade costs. The SSR212MC2 also supports SAS HDDs, which offer enterprise-class reliability. With spindle speeds of 10,000 RPM and 15,000 RPM, and an architecture that enables a point-to-point connection and full-duplex, or bi-directional, data transfers, SAS HDDs offer performance and reliability similar to SCSI or Fibre Channel HDDs.

Intel has engaged with storage software providers to ensure the availability of a variety of software solutions. These include applications that allow the Intel Storage Server SSR212MC2 to be configured as a SAN or a NAS system.

Intel is enabling a robust set of hardware options to provide high bandwidth storage and server connectivity. Dual- and quad-port Intel PRO server adapters provide an option for increased bandwidth through bonding of ports, or reliability via failover. Additional options will include, 10 Gb Ethernet, 4 Gbps Fibre Channel connectivity, and 20 Gbps Infiniband connectivity.

Environments ranging from high-performance computing to the growing compute, networking, and storage needs of small and medium businesses can all benefit from the flexible network connectivity options available, via add-in cards, with the SSR212MC2.

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Database System: MySQL and PostgreSQL

noreply@blogger.com (Tigre de Fogo) — Fri, 26 Sep 2008 19:18:00 +0000

Database System: MySQL and PostgreSQL
by dbConcert

MySQL
The MySQL database has become the world's most popular open source database because of its consistent fast performance, high reliability and ease of use. It's used in more than six million installations ranging from large corporations to specialized embedded applications on every continent in the world. It's also become the database of choice for a new generation of applications built on the LAMP stack (Linux, Apache, MySQL, PHP / Perl / Python.) MySQL runs on more than twenty platforms including Linux, Windows, OS/X, HP-UX, AIX, Netware, giving you the kind of flexibility that puts you in control.

PostgreSQL
PostgreSQL is a powerful, open source relational database system. It has more than 15 years of active development and a proven architecture that has earned it a strong reputation for reliability, data integrity, and correctness. It runs on all major operating systems and boasts sophisticated features such as Multi-Version Concurrency Control (MVCC), point in time recovery, tablespaces, asynchronous replication, nested transactions (savepoints), online/hot backups, a sophisticated query planner/optimizer, and write ahead logging for fault tolerance. It is highly scalable both in the sheer quantity of data it can manage and in the number of concurrent users it can accommodate. There are active PostgreSQL systems in production environments that manage in excess of four terabytes of data.

What it Takes to Become a Quality Web Hosting Provider

noreply@blogger.com (Tigre de Fogo) — Thu, 18 Sep 2008 22:07:00 +0000

What it Takes to Become a Quality Web Hosting Provider
by Bob Willis

The demand for quality web hosting service has reached dizzying heights and web-hosting companies are constantly vying for the top spots and higher search engine rankings in order to acquire a larger customer base. Since every website that is created, requires a web host to create a web presence, web hosting is an indispensable aspect and this led to mushrooming of web hosting companies. In a bid to lure customers, certain companies are offering dearth cheap deals and prices and while some people may want to grab these, there are people who would view these quite warily. That being said, there is no fixed formula as even affordable web hosting can offer quality services and the expensive ones might not live up to the customers' expectations. It is therefore imperative to perform a thorough research on the background, history and reliability of the company before buying their hosing packages. There are a number of aspects that factor into what exactly constitutes a top web hosting company.

Firstly, it is important that the web-hosting provider has certain recognition in the hosting industry, as that would reflect its credibility. Also take into account the number of years the company has been in the business of web hosting. This is to save yourself from the fly-by-night companies and thereby minimize the risk factor. The web hosting market is fiercely competitive and therefore a company that is offering value-added features and services, speed and reliability should be given a preference value. It is therefore advisable to give priority to a web hosting company that has been around for a while.

Secondly, any top hosting company would offer dependability of servers, maximum uptime (minimum being 99%), speed and reliability as well as validity of their claims. In order to find out these things, one has to perform an independent research by reading customer reviews posted on unbiased websites rather than the seemingly promotional reviews. It is fairly simple to tell a promotional review from a real review, as a promotional review would only highlight the positive aspects of the provider's services. Hence, dependability of the hosting service and its servers becomes paramount and is an important aspect that must be considered to determine the supremacy of the web hosting company.

A company that offers quality customer support and technical support can be also be considered a reliable web-hosting provider. In fact, customers weigh this as a prime factor during the selection process and this is what it takes to become a top web-hosting provider.

Web hosting providers should be able to offer all the essentials that the website requires for its smooth functionality and ensure that no hidden costs are involved. Do not get lured into cheap deals and look for affordability coupled with quality services, tools, features and application support.

A company that values its customers, offers affordability, quality services and most importantly employs high-end techniques and expertise can be considered among the top web hosting providers in the industry.

Books - Excerpt: Operating System Concepts by Silberschatz, Galvin, Gagne

noreply@blogger.com (Tigre de Fogo) — Mon, 01 Sep 2008 19:58:00 +0000

Books - Excerpt: Operating System Concepts by Abraham Silberschatz, Peter Baer Galvin, Greg Gagne

Book: Operating System Concepts

Implementation

Although the virtual machine concept is useful, it is difficult to implement. Much effort is required to provide an exact duplicate of the underlying machine. Remember that the underlying machine has two modes: user mode and monitor mode. The virtual-machine software can run in monitor mode, since it is the operating system. The virtual machine itself can execute in only user mode. Just as the physical machine has two modes, however, so must the virtual machine. Consequently, we must have a virtual user mode and a virtual monitor mode, both of which run in a physical user mode. Those actions that cause a transfer from user mode to monitor mode on a real machine (such as a system call or an attempt to execute a privileged instruction) must also cause a transfer from virtual user mode to virtual monitor mode on a virtual machine.

This transfer can generally be done fairly easily. When a system call, for example, is made by a program running on a virtual machine, in virtual user mode, it will cause a transfer to the virtual-machine monitor in the real machine. When the virtual-machine monitor gains control, it can change the register contents and program counter for the virtual machine to simulate the effect of the system call. It can then restart the virtual machine, noting that it is now in virtual monitor mode. If the virtual machine then tries, for example, to read from its virtual card reader, it will execute a privileged I/O instruction. Because the virtual machine is running in physical user mode, this instruction will trap to the virtual-machine monitor. The virtual-machine monitor must then simulate the effect of the I/O instruction. First, it finds the spooled file that implements the virtual card reader. Then, it translates the read of the virtual card reader into a read on the spooled disk file, and transfers the next virtual "card image" into the virtual memory of the virtual machine. Finally, it can restart the virtual machine. The state of the virtual machine has been modified exactly as though the I/O instruction had been executed with a real card reader for a real machine executing in a real monitor mode.

The major difference is, of course, time. Whereas the real I/O might have taken 100 milliseconds, the virtual I/O might take less time (because it is spooled) or more (because it is interpreted). In addition, the CPU is being multiprogrammed among many virtual machines, further slowing down the virtual machines in unpredictable ways. In the extreme case, it may be necessary to simulate all instructions to provide a true virtual machine. VM works for IBM machines because normal instructions for the virtual machines can execute directly on the hardware. Only the privileged instructions (needed mainly for I/O) must be simulated and hence execute more slowly.

Benefits

The virtual-machine concept has several advantages. Notice that in this environment there is complete protection of the various system resources. Each virtual machine is completely isolated from all other virtual machines, so there are no security problems. On the other hand, there is no direct sharing of resources. To provide sharing, two approaches have been implemented. First, it is possible to share a minidisk. This scheme is modeled after a physical shared disk, but is implemented by software. With this technique, files can be shared. Second, it is possible to define a network of virtual machines, each of which can send information over the virtual communications network. Again, the network is modeled after physical communication networks, but is implemented in software.

Such a virtual-machine system is a perfect vehicle for operating-systems research and development. Normally, changing an operating system is a difficult task. Because operating systems are large and complex programs, it is difficult to be sure that a change in one point will not cause obscure bugs in some other part. This situation can be particularly dangerous because of the power of the operating system. Because the operating system executes in monitor mode, a wrong change in a pointer could cause an error that would destroy the entire file system. Thus, it is necessary to test all changes to the operating system carefully.

The operating system, however, runs on and controls the entire machine. Therefore, the current system must be stopped and taken out of use while changes are made and tested. This period is commonly called system-development time. Since it makes the system unavailable to users, system-development time is often scheduled late at night or on weekends, when system load is low.

A virtual-machine system can eliminate much of this problem. System programmers are given their own virtual machine, and system development is done on the virtual machine, instead of on a physical machine. Normal system operation seldom needs to be disrupted for system development.

Virtual machines are coming back into fashion as a means of solving system compatibility problems. For instance, there are thousands of programs available for MS-DOS on Intel CPU-based systems. Computer vendors like Sun Microsystems and Digital Equipment Corporation (DEC) use other, faster processors, but would like their customers to be able to run these MS-DOS programs. The solution is to create a virtual Intel machine on top of the native processor. An MS-DOS program is run in this environment, and its Intel instructions are translated into the native instruction set. MS-DOS is also run in this virtual machine, so the program can make its system calls as usual. The net result is a program which appears to be running on an Intel-based system but is really executing on a very different processor. If the processor is sufficiently fast, the MS-DOS program will run quickly even though every instruction is being translated into several native instructions for execution. Similarly, the PowerPC-based Apple Macintosh includes a Motorola 68000 virtual machine to allow execution of binaries that were written for the older 68000-based Macintosh.

Java

Another example of the continued utility of virtual machines involves the Java language. Java is a very popular language designed by Sun Microsystems. Java is implemented by a compiler that generates bytecode output. These bytecodes are the instructions that run on the Java Virtual Machine (JVM). For Java programs to run on a platform, that platform must have a JVM running on it. The JVM runs on many types of computer, including IBM-Compatible PC, Macintosh, Unix workstation and server, and IBM minicomputer and mainframe. The JVM is also implemented within web browsers such as Microsoft Internet Explorer and Netscape Communicator. These browsers, in turn, run on top of varying hardware and operating systems. The JVM is also implemented on the small JavaOS, which implements the JVM directly on hardware to avoid the overhead imposed by running Java on general-purpose operating systems. Finally, single-purpose devices such as cellular phones can be implemented via Java through the use of microprocessors that execute Java bytecodes as native instructions.

The Java Virtual Machine implements a stack-based instruction set that includes the expected arithmetic, logical, data movement, and flow control instructions. Because it is a virtual machine, it can also implement instructions that are too complex to be built in hardware, including object creation, manipulation, and method invocation instructions. Java compilers can simply emit these bytecode instructions, and the JVM must implement the necessary functionality on each platform.

The design of Java takes advantage of the complete environment that a virtual machine implements. For instance, the bytecodes are checked for instructions that could compromise the security or reliability of the underlying machine. The Java program is not allowed to run if it fails this check. Through the implementation of Java as a language that executes on a virtual machine, Sun has created an efficient, dynamic, secure, and portable object-oriented facility. Although Java programs are not as fast as programs that compile to the native hardware instruction set, they nevertheless are more efficient than interpreted programs and have several advantages over native-compilation languages such as C.

System Design and Implementation

In this section, we discuss the problems of designing and implementing a system. There are, of course, no complete solutions to the design problems, but there are approaches that have been successful.

Why Use Geographical Information Systems?

noreply@blogger.com (Tigre de Fogo) — Sun, 17 Aug 2008 19:59:00 +0000

Why Use Geographical Information Systems?
by Georgio Galveston

GIS have become a focal point and a saviour for many businesses and organizations where geographical images and maps are a main component of their everyday lives. Geographical Information Systems is a technology which allows users to create, analyze, edit, customize and render geographical data such as maps. GIS's have numerous uses across a varied range of industries. It used to be very expensive to run Geographical Information Systems, but now with GIS hosting and map hosting technologies becoming more common and easier to implement, alongside the development of open source applications, it has become relatively cheap to run GIS, here are some of the most common uses for it:

Create Maps
Geographical Information Systems is an essential tool for people who are looking to create and make geographical maps public or private on the internet. It deals with the data and renders it in many ways to make it accessible and suitable for online publication. An example application would be Google Maps which is very popular software available worldwide.

Teaching
Studies have found having visual aids in teaching classes holds the attention of student more than just talking, in classes such as geography, the teacher can use Geographical Information Systems to show maps on a projector to help them with getting their points across and teaching specific areas of knowledge.

Crisis management
Crisis management officers can use special awareness aspect of GIS systems to plan procedures if a crisis happens in a certain town or city, it can lead to a more effective decision making process as they have the geographical data in front of them.

Other uses of Geographical Information Systems include pollution analysis and control and human resource management. The possibilities are endless. When choosing to implement GIS, it is important to choose a suitable GIS hosting package, make sure the host have the capabilities to handle the advanced technological abilities a Geographical Information Systems possesses.

Web Hosting Servers: Windows or Linux

noreply@blogger.com (Tigre de Fogo) — Tue, 29 Jul 2008 01:03:00 +0000

Web Hosting Servers: Windows or Linux
by Arvind Sharma

Once a web site is ready, the next confusing thing is the server on which the website goes on. Deciding on a website hosting service is something that might get anybody perplexed. There are mainly two types of web hosting services - Windows and Linux. If the business is small then you can even try out the Shared Linux and Windows hosting service. Windows as well as Linux website host services have different benefits and limitations.

Linux hosting is one of the most common and significant hosting service on the net. The main reason for this webhosting is that many companies which are using it are open sources and quite affordable compared to Windows. Linux is much easier to manage as the business grows online. Windows hosting supports all operational functions of Windows system. It maintains programming frameworks such as ColdFusion and ASP.net. It also backs SQL servers which is extremely useful when creating a website regarding a searchable list. Windows hosting service is apt for people who are used to Microsoft based technologies or equipments.

The biggest difference between these two hosting services is the cost factor. Linux services are much low-priced in comparison to Windows. Money does play an important in website hosting especially when new web owners are starting off. But, the main reason for Windows hosting service costs to be higher is the fact that many Windows technologies are licensed. Windows also scores over Linux in the programming department; there are many Windows softwares which are not supported on Linux operating systems.

After drafting out your needs, you can also consult professionals in the website hosting field on which is a better option. But, it is always advisable to weigh the pros and cons before making that choice, so that you do not regret in any possible where. There are many hosting companies that can help you with the right webhosting solution which will take away all your tension and your entire job will be done within moments. But, make sure to do a reference check before hiring any company's service.

What is PHP Hypertext Preprocessor Scripting Language?

noreply@blogger.com (Tigre de Fogo) — Thu, 24 Jul 2008 18:33:00 +0000

What is PHP Hypertext Preprocessor Scripting Language?

PHP refers to PHP Hypertext Preprocessor. PHP is a widely-used open source general-purpose computer scripting language created by Rasmus Lerdorf in 1995, and is especially suited for Internet development and can be embedded into HTML.

You can create dynamic web pages with the PHP scripting language. You can embed PHP commands within a standard HTML page. PHP's syntax is similar to that of C and Perl, making it easy to learn for anyone with basic programming skills.

A dynamic PHP Web page interacts with the user, so that each user visiting the page sees customized information. PHP can also be used to create dynamic web pages that are generated from information accessed from a MySQL database.

PHP offers connectivity to most of the common databases, although currently only MySQL is supported on the central webservers. PHP has hundreds of base functions and thousands more from extensions. PHP offers integration with various external libraries, which allow the developer to do anything from generating PDF documents to parsing XML.

As of April 2007, over 20,000,000 Internet websites were hosted on web servers with PHP scripting language installed.

ATI Radeon HD 4850 and 4870: The First Teraflops Graphics Chips

noreply@blogger.com (Tigre de Fogo) — Mon, 21 Jul 2008 00:25:00 +0000

ATI Radeon HD 4850 and 4870: The First Teraflops Graphics Chips

The ATI Radeon 4800 series represents a 2X performance jump over the ATI Radeon HD 3800 GPU, the biggest generational increase since the game-changing launch of the Radeon 9700 in 2002. The ATI Radeon 4800 series sets a new industry standard in key metrics such as performance-per-watt, performance-per-mm2 of chip die size, and performance-per-dollar.

In performance, the ATI Radeon HD 4850 and ATI Radeon HD 4870 just blew past competing cards at their respective price levels. Each draws less power and produces less fan noise for this level of performance as well. To cap it off, the driver support is solid. The ATI Radeon HD 4800 series represents a huge leap forward for AMD.

With that kind of performance and the addition of visual enhancements made possible by DirectX 10.1 and tessellation, gamers can now achieve cinema-quality realism. It’s an incredible step forward in gaming and Alienware is looking forward to introducing the ATI Radeon HD 4800 series in the near future.

Industry excitement for the ATI Radeon HD 4800 series is evidenced in one dozen AIB (Add-In-Board) companies offering custom designs of the products, a record number for AMD. Building high-performance versions of the ATI Radeon HD 4800 series are VisionTek, ASUS, PowerColor, MSI, GIGABYTE, GECUBE, Force3D, SAPPHIRE Technology, Diamond Multimedia, Club 3D, HIS (Hightech Information Systems) and Palit Multimedia.

Systems integrators launching ATI Radeon HD 4800 series include ABS, Alienware, AMAX, Canada Computers, CyberPower, Extreme PC Corporation, Falcon-Northwest, iBUYPOWER, Maingear, Systemax, Ultra Gaming and Velocity Micro.

Web Hosting: PHP and MySQL

noreply@blogger.com (Tigre de Fogo) — Fri, 11 Jul 2008 12:34:00 +0000

Web Hosting: PHP and MySQL
by Helen Cox

Both PHP and MySQL are popular web hosting applications. It is safe to say that both PHP and MySQL are essential components when it comes to running the popular Content Management Systems. A prime example of the popularity and the essentialness of PHP and MySQL can be seen within Wikipedia. This is because wiki runs on what is known as Mediawiki software; this software is wrote using PHP script and uses a MySQL database.

So what exactly is PHP and MySQL?
PHP (a recursive acronym for PHP: Hypertext Pre-processor) is a form of computer scripting language, which was originally designed for the production of dynamic web pages. It is a widely used general purpose scripting language, which is especially suited for web development as it can easily be embedded into HTML and generally runs on a web server, taking PHP code as its input and creating web pages as output. It can be deployed on most web servers and on almost every operating system and platform free of charge. So far it is safe to say that PHP is installed on more than 20 million websites as well as one million web servers. PHP is also the most popular Apache module among computers using Apache as a web server. Apache is primarily used to serve both static content and dynamic Web pages on the World Wide Web. Many web applications are designed expecting the environment and features that Apache provides.

Recently, on May 1st 2008 the most major release of PHP came out, which is version 5.2.6. This version, as with previous versions can be developed on most web servers as well as many operating systems and platforms; it can also be used with many relational database management systems. Also the PHP Group provides the complete source code, which allows users to build and customise as well as extend it to fit their own use.

PHP's programming syntax is very similar to that of a programme called Perl and due to the elegant design used, PHP makes it possible for anyone to learn how to use it. Also, unlike other scripting languages, PHP supports the most common databases like Oracle, Sybase and MySQL. It is also possible to integrate external libraries to generate PDF documents or parsing XML. PHP is an open-source language and is supported by a large group of developers.

MySQL
MySQL is a database management system. MySQL is what is known as an Open Source SQL database, SQL is a standard interactive and programming language for querying and modifying data and managing databases. MySQL is very fast, reliable, and easy to use. It also has a very practical set of features developed in very close cooperation with its users. When MySQL was originally developed it was done so as a way of handling very large databases, which are much faster than existing solutions and have been successfully used in highly demanding production environments for many years. MySQL is also one programme that is under constant development and today MySQL offers a rich and very useful set of functions. The connectivity, speed and security that are brought to you by MySQL makes it highly suited for accessing databases on the Internet. It has more than 11 million installations and runs as a server providing multi-user access to a number of databases.

Intel Server Systems SR1560SF and SR1560SFHS

noreply@blogger.com (Tigre de Fogo) — Fri, 04 Jul 2008 04:23:00 +0000

Intel Server Systems SR1560SF and SR1560SFHS

Rack-Optimized, Highly Integrated Server Systems Designed for High Performance Computing and High-Density Data Centers

The Intel Server Systems SR1560SF and SR1560SFHS represent Intel's latest generation of rack-optimized server solutions. These systems deliver a large memory footprint, fast system bus, and high I/O bandwidth-critical features for High Performance Computing (HPC) applications as well as data centers and general purpose enterprise-class computing needs.

Both solutions are designed for space-constrained environments:

Intel Server System SR1560SF—1U fixed drive system supports two 3.5" SATA drives in quick release drive carriers.

Intel Server System SR1560SFHS—1U hot swap drive system supports three 3.5" SATA drives with the optional passive backplane or three 3.5" SAS/SATA drives with the optional active backplane.

Features and benefits

Support for dual-core and quad-core processors
Significantly increased server performance without an increase in power consumption.

Dual independent bus architecture
Enables dedicated data flow to each processor, maximizing system performance.

Fully buffered DIMM memory
Increases capacity and memory bandwidth to keep pace with the processor and I/O performance enhancements.

Intel Extended Memory 64 Technology (Intel EM64T)
Extends the amount of available server memory.

Intel I/O Acceleration Technology (Intel I/OAT)
A platform innovation that helps get network data to and from server applications faster, while consuming far fewer CPU cycles.

Intel Virtualization Technology (Intel VT)
Turns a physical server into multiple systems (virtual machines) allowing multiple operating systems and applications to run inside a single platform.

Execute Disable Bit
Reduces exposure to viruses and prevents harmful software from executing on the server or network.

Enhanced Intel SpeedStep Technology
Allows processors to adjust their operating speeds to meet varying performance needs, while balancing power consumption.

Specifications

Processors
Quad-Core Intel Xeon processor 5400 sequence and Dual-Core Intel Xeon processor 5200 sequence.

Memory capacity
Sixteen Fully Buffered DIMM (FBDIMM) sockets for up to 64 GB of registered ECC DDR2 667MHz memory.

Integrated management
IPMI 2.0-compliant onboard platform instrumentation.

Software
Intel Server Essentials software.

System BIOS
8Mb Flash EEPROM with EFI BIOS, Multiboot BBS (BIOS Boot Specification) 1.4-compliant.

Special features
Plug and play, IDE drive auto-configure, SMBIOS 2.3, ECC/parity support, multilingual support, enabled for rolling/online BIOS updates.

Intel G965 Express Chipset Features

noreply@blogger.com (Tigre de Fogo) — Tue, 24 Jun 2008 09:05:00 +0000

Intel G965 Express Chipset Features

Features:
Supports Intel® Core™2 Processor with Viiv™ Technology
Get ready for a new kind of consumer entertainment PC that will change the way you enjoy entertainment at home. With a system based on the Intel® G965 Express Chipset, control the music, movies, games, and photos you want to enjoy both from your personal entertainment collections and endless entertainment options from a wide range of Intel® Core™2 processor with Viiv™ technology verified service providers delivered right to your living room.

1066/800/533 MHz System Bus
Supports the Intel® Core™2 Duo processor with Intel® Virtualization Technology, Intel® Pentium® D processor 900, Intel® Pentium® 4 processor with Hyper-Threading (HT) Technology and all other Intel® processors using the LGA775 socket.

PCI Express Interface
The PCI Express x16 graphics interface supports the latest high-performance graphics cards. The PCI Express x1 I/O ports offer up to 3.5X the bandwidth over traditional PCI architecture, delivering faster access to peripheral I/O devices.

Intel® Fast Memory Access (Intel® FMA)
Updated Graphics Memory Controller Hub (GMCH) backbone architecture that improves system performance by optimizing the use of available memory bandwidth and reducing the latency of the memory accesses.

Dual-Channel DDR2 Memory Support
Delivers up to 12.8 GB/s of bandwidth and 8GB memory addressability for faster system responsiveness and support of 64-bit computing.

Intel® Graphics Media Accelerator X3000
3D enhancements enable greater game compatibility with support for Hardware T&L, and improved realism with support for Microsoft DirectX 9.0c Shader Model 3.0, OpenGL 1.5, and floating point operations. Intel graphics technology also support the highest levels of the Microsoft Vista Aero experience.

Intel® Clear Video Technology
Video processing hardware and software delivers enhanced high-definition video playback, sharper images with advanced de-interlacing, and advanced ProcAmp color controls.

Support for High Definition Multimedia Interface (HDMI)
HDMI delivers uncompressed HD video and uncompressed multi-channel audio in a single High Definition Multimedia Interface (HDMI) cable, supporting all HD formats including 720p, 1080i and 1080p.

Intel® High Definition Audio (Intel® HD Audio)
Integrated audio support enables premium digital sound and delivers advanced features, such as multiple audio streams and jack re-tasking. The Dolby PC Entertainment Experience 5 is available exclusively on systems with Intel High Definition Audio.

Intel® Matrix Storage Technology
With a second hard drive added, provides quicker access to digital photo, video and data files with RAID 0, 5, and 10, and greater data protection against a hard disk drive failure with RAID 1, 5, and 10. Support for external SATA (eSATA) enables the full SATA interface speed outside the chassis, up to 3 Gb/s.

Serial ATA (SATA)
3 Gbp/s High-speed storage interface supports faster transfer rate for improved data access.

USB Port Disable
Enables individual USB ports to be enabled or disabled as needed. This feature provides added protection of data by preventing malicious removal or insertion of data through USB ports.

Intel® Quiet System Technology (Intel® QST)
Intelligent system fan speed control algorithms use operating temperature ranges more efficiently to reduce perceived system noise by minimizing fan speed changes.

Supercomputing: AMD Processor Breaks 1 Teraflop Barrier

noreply@blogger.com (Tigre de Fogo) — Wed, 18 Jun 2008 05:26:00 +0000

Supercomputing: AMD Processor Breaks 1 Teraflop Barrier

At the International Supercomputing Conference, AMD introduced its next-generation stream processor, the AMD FireStream 9250, specifically designed to accelerate critical algorithms in high-performance computing (HPC), mainstream and consumer applications. Leveraging the GPU design expertise of AMD’s Graphics Product Group, AMD FireStream 9250 breaks the one teraflop barrier for single precision performance. It occupies a single PCI slot, for unmatched density and with power consumption of less than 150 watts, the AMD FireStream 9250 delivers an unprecedented rate of performance per watt efficiency with up to eight gigaflops per watt.

Customers can leverage AMD’s latest FireStream offering to run critical workloads such as financial analysis or seismic processing dramatically faster than with CPU alone, helping them to address more complex problems and achieve faster results. For example, developers are reporting up to a 55x performance increase on financial analysis codes as compared to processing on the CPU alone, which supports their efforts to make better and faster decisions. Additionally, the use of flexible GPU technology rather than custom accelerators assists those creating application-specific systems to enhance and maintain their solutions easily.

The AMD FireStream 9250 stream processor includes a second-generation double-precision floating point hardware implementation delivering more than 200 gigaflops, building on the capabilities of the earlier AMD FireStream 9170, the industry’s first GP-GPU with double-precision floating point support. The AMD FireStream 9250’s compact size makes it ideal for small 1U servers as well as most desktop systems, workstations, and larger servers and it features 1GB of GDDR3 memory, enabling developers to handle large, complex problems.

Driving broad consumer adoption with open systems
AMD enables development of the FireStream family of processors with its AMD Stream SDK, designed to help developers create accelerated applications for AMD FireStream, ATI FireGL™ and ATI Radeon™ GPUs. AMD takes an open-systems approach to its stream computing development environment to ensure that developers can access and build on the tools at any level. AMD offers published interfaces for its high-level language API, intermediate language, and instruction set architecture; and the AMD Stream SDK’s Brook+ front-end is available as open source code.

In keeping with its open systems philosophy, AMD has also joined the Khronos Compute Working Group. This working group’s goals include developing industry standards for data parallel programming and working with proposed specifications like OpenCL. The OpenCL specification can help provide developers with an easy path to development across multiple platforms.

“An open industry standard programming specification will help drive broad-based support for stream computing technology in mainstream applications,” said Rick Bergman, senior vice president and general manager, Graphics Product Group, AMD. “We believe that OpenCL is a step in the right direction and we fully support this effort. AMD intends to ensure that the AMD Stream SDK rapidly evolves to comply with open industry standards as they emerge.”

Accelerating industry adoption
The growth of the stream computing market has accelerated over the past few years with Fortune 1000 companies, leading software developers and academic institutions utilizing stream technology to achieve tremendous performance gains across a variety of applications.

“Stream computing is increasingly important for mainstream and consumer applications and is no longer limited to just the academic or engineering industries. Today we are truly seeing a fundamental shift in emerging system architectures,” said Jon Peddie, president, Jon Peddie Research. “As the industry’s only provider of both high-performance discrete GPUs and x86-compatible CPUs, AMD is uniquely well-suited to developing these architectures.”

AMD customers, including ACCIT, Centre de Physique de Particules de Marseille, Neurala and Telanetix are using the AMD Stream SDK and current AMD FireStream, ATI FireGL or ATI Radeon boards to achieve dramatic performance gains on critical algorithms in HPC, workstation and consumer applications. Currently, Neurala reports that it is achieving 10-200x speedups over the CPU alone on biologically inspired neural models, applicable to finance, image processing and other applications.

AMD is also working closely with world class application and solution providers to ensure customers can achieve optimum performance results. Stream computing application and solution providers include CAPS entreprise, Mercury Computer Systems, RapidMind, RogueWave and VizExperts. Mercury Computer Systems provides high-performance computing systems and software designed for complex image, sensor, and signal processing applications. Its algorithm team reports that it has achieved 174 GFLOPS performance for large 1D complex single-precision floating point FFTs on the AMD FireStream 9250.

Pricing and availability
AMD plans to deliver the FireStream 9250 and the supporting SDK in Q3 2008 at an MSRP of $999 USD. AMD FireStream 9170, the industry’s first double-precision floating point stream processor, is currently available for purchase and is competitively priced at $1,999 USD.

Website: Optimizing Photos and Graphics

noreply@blogger.com (Tigre de Fogo) — Fri, 13 Jun 2008 04:32:00 +0000

Website: Optimizing Photos and Graphics
by Michelle Roberts

The average web user will only wait up to 8 seconds for a page to display. With the optimum web page size being less than 100k, if you're in an industry where images are your business, optimizing those images for your web site can be crucial.

Optimizing web graphics correctly involves finding the right balance between image quality and image size. As each image should certainly be no more than 30k in size, following these three steps will optimize your images and make your page load faster.

Resize the Image

Using a photo or image editing software package, you can re-size or crop your image or photograph to the correct dimensions that it will need to be for the website space. This is a better method than resizing the image within your html WYSIWYG editor, as despite the change in appearance, the image file size will remain unchanged.

Decrease the number of colours

Reducing the amount of colours used in an image file will also reduce the file size. Again, within your image editing software, you can reduce the amount of colours that an image is using, ensuring that little necessary detail or quality is lost. For example if you have a black and red logo saved as a .gif file, there should be no significant loss of quality to limit the colours from 256 colours to 4-8 colours which will notably reduce the file size. If your image uses gradients and you are finding that you are getting colour blocks across the gradient areas, simply add some dithering to your optimized file. Dithering will increase the file size so you may have to get the balance between colours and dithering right for optimum size. You should however still find the image size significantly reduced despite the use of dithering.

State the height and width of your image

Whenever you use an image on your website, you should always try to include both the image height and width attributes in your html. This will allow the browser to quickly identify the size of the image, and move on to loading the rest of the page without having to wait for the image to load, thus increasing your load speed.

Choosing the correct file format

An important way to reduce image sizes is to use the appropriate file type suitable for an image. There are two common file types used for websites graphics, Gif and JPEG.

GIFs
Most of your web images should really be saved as a gif file. A general rule of which file type to use, would be that most images except photographs should be a .gif file. This includes, simple line drawings, shapes, small icons, anything that isn't too complex.

GIF files are loss-less compressed image files, which means that the image files can be compressed with no loss of data. However, gif files are limited to 256 colors or less, which is why they are generally not suitable for images. Gif files will also allow you to use transparent backgrounds, so that you can display your images on coloured or pattern backgrounds.

JPEGs
Jpegs should only ever be used for photographs or more complex images that use a large amount of gradients. Image sizes are larger than gif files, however, image size can be compressed by reducing the image quality. You will need to experiment to find the right balance between quality and size. You should try to bring down the image quality as much as is possible before losing too much definition of the image. This will generally be about 50% reduction, although further reductions may be possible if necessary.

Utilizing the browser cache

A final way to reduce the speed loading times on your website is to wherever possible, use the same images throughout the site.

A browser's Cache is an area on the local hard drive that stores recently used images. When a browser views a page with image files, the browser will download the file and display that file within your browser. If you move to another page with the same image, the browser is able to identify the image and display it directly from the cache, without having to re-download the image once again. Which means that if you can use common images throughout your website, the loading times will be faster as the images will be ready and available for quick display.

Using this guide to optimize your images for your website, can significantly reduce your html document size, which will increase your page load speed. Beware, it can become addictive, and you can optimize too much. Don't sacrifice quality too much for the sake of speed. Nobody wants to view ugly websites with grainy, pixilated images.

Microsoft Releases Dynamics AX 2009

noreply@blogger.com (Tigre de Fogo) — Tue, 03 Jun 2008 00:27:00 +0000

Microsoft Releases Dynamics AX 2009

Microsoft announced the general availability of Microsoft Dynamics AX 2009, an adaptable business management solution that offers powerful new capabilities to help growing multisite organizations streamline processes, reduce operational costs, manage compliance and drive informed decision-making.

As businesses expand globally, so does the complexity of managing accurate business insights and standardizing operations across multiple locations. Microsoft Dynamics AX 2009 offers new multisite and shared services capabilities, enabling customers to manage complex financial and supply chain processes more easily. For example, the new software can run multiple legal entities on a central installation and provide a single, integrated view of financial and supply chain information from facilities around the world, helping organizations simplify global planning. Advanced planning and reporting scenarios, such as consolidation and budgeting, are offered through integration with Microsoft Office PerformancePoint Server.

“With its innovative role-based user experience, improved reporting and BI capabilities, and improving platform harmonization, Microsoft Dynamics products should be on ERP selection shortlists for a variety of SMBs, particularly those that use Microsoft’s server-based products,” wrote R “Ray” Wang of Forrester Research Inc. in the firm’s report “Microsoft Dynamics Gets Renewed Focus” in April 2008. “Multisite companies should consider Dynamics AX.”

Another business challenge that growing companies face is the increasing pressure to meet global and local regulatory compliance, a complex and costly problem that has been a top priority for chief executive officers and chief financial officers. Microsoft Dynamics AX 2009 delivers core features to help companies limit these risks and lower total cost of compliance, including the following:

A compliance center that provides one central, integrated view of internal controls, key performance indicators (KPIs) and other compliance data
Embedded workflows that automate business processes, enforcing standard operating procedures to limit organizational risks while still enabling organizations to quickly respond to changing market needs
Country-specific functionality to help customers more easily comply with local regulations in 36 countries

“Managing risk is an integral part of my job, and Microsoft Dynamics AX makes my job easier,” said John Elmer, vice president, information systems, and controller, the Rodgers & Hammerstein Organization. “I can access critical company information from within the Executive Role Center and see a 360-degree view of our global IT and finance operations, ranging from compliance risks to how the company is tracking against forecasts.” The Rodgers & Hammerstein Organization, based in New York, represents a wide variety of entertainment copyrights for more than 200 writers, including Richard Rodgers and Oscar Hammerstein II, through its theatrical, concert and music publishing divisions.

In a fast-paced world, people need software that helps them do their jobs more effectively and with minimal training. To increase productivity and foster more confident decision-making, the RoleTailored design of Microsoft Dynamics AX 2009 gives employees access to critical business data through the following new features:

A Role Center that prioritizes tasks and real-time information for a majority of business functions
A user interface that looks and feels like familiar Microsoft Office software to help employees ramp up quickly, resulting in higher user productivity and more consistent adherence to business processes
Self-service business intelligence tools using Microsoft Business Intelligence technologies to deliver standard KPIs by role and simplify end-user reporting, which results in more informed decision-making and integrity of information across the organization. Preconfigured KPIs and reports enable customers to start immediately.

“Microsoft Dynamics AX 2009 signals a new chapter in enterprise resource planning (ERP) user productivity,” said Mogens Elsberg, general manager for Microsoft Dynamics ERP. “Employees using traditional ERP systems have had to wade through inefficient, time-intensive steps — enter transactional data, run reports, analyze reports — before they can do their jobs effectively. Through Microsoft Dynamics AX 2009’s Role Center, employees from the executive suite to the warehouse have access to role-relevant business intelligence to help them make decision more efficiently. The Role Center provides a centralized view of each person’s prioritized work lists based on their organization’s configurable business processes and clearly identifies specific steps to take, thereby optimizing productivity.”

Microsoft Dynamics AX 2009 integrates with other leading Microsoft technologies, maximizing the benefits of any company’s overall IT investment. Benefits include the following:

Enhanced security, reliability and scalability though integration with Microsoft SQL Server 2008. For example, Microsoft Dynamics AX 2009, through Microsoft SQL Server 2008, can compress the database size by 40 percent to 60 percent, which can lead to lower hardware and data maintenance costs.
Reduced operational complexity and IT management overhead with improved control through interoperability with Windows Essential Business Server 2008
Improved ability to manage and administer projects through integration with Microsoft Office Project Server
Easy communication with remote employees, customers and trading partners through integration with Microsoft unified communications

Microsoft Dynamics AX 2009 is available in Austria, Canada, Denmark, Finland, France, Germany, Iceland, Ireland, Italy, Malaysia, Mexico, the Netherlands, Norway, Singapore, Spain, South Africa, Sweden, Switzerland, Thailand, the United Kingdom and the United States. It will be available in additional countries at a later date.

Internet Security: 10 Tips You Need to Know

noreply@blogger.com (Tigre de Fogo) — Fri, 30 May 2008 16:56:00 +0000

Internet Security: 10 Tips You Need to Know
by Diane Ledo

Just a few simple things can keep all of that sensitive personal information on your laptop away from the prying eyes of others. It really does not take a lot of time or effort and failure to do so is just asking for trouble. Hoping that no one will ever try to access your data will not work, but with some security measures which can be implemented in a matter of minutes you can be far more secure.

01. Your first step should be to set up a firewall. Especially if you use your laptop on the road, doubly so in public WiFi hot spots, you need a firewall installed and running. These access points are not secure, so everyone has to take action to protect themselves.

02. Very important is to disable Ad-hoc mode on your Wi-Fi card. You should use only connections which you have set up using your own, or XP's built in tools. An instant network you've never heard of may very well be bad news. Definitely disable Ad-hoc mode before entering a hot spot, there may be networks present, most of which you do not want to access and you most certainly do not want accessing your computer.

03. Disabling all file and printer sharing when you are not in the home or office is an important security measure. You should get into this habit; otherwise when you're connected in a hot spot, you are leaving your laptop open to all users in the area. It only takes a few seconds to turn off file and printer sharing - you can turn it back on when you need it and this step will keep a lot of potential trouble from ever happening.

04. You can further protect personal information my making the folders which contain them private. This also takes only a moment and gives you an extra layer of security. Your information is still there of course, but is now far more difficult for others to look at.

05. Password protection is another good idea. You can even password protect individual files. There's plenty of software available which can take care of this task. The password can be the same for each file you want to password protect, or each can have a unique password. Again, this is a good security measure to undertake before connecting in a hot spot.

06. You should also take steps to ensure the security of your laptop at home. This entails a security cable to lock your laptop down to a strong, stable surface. Lock up your laptop whenever you are not using it - this will make it quite difficult for anyone to steal it, even if your home is burglarized.

07. Some newer laptops have hardware-level security measures built in, such as encryption. Your data becomes almost impossible for others to gain access to - all of your files are protected by a layer of encryption before any hacker can even get to the operating system. Laptops with this level of security include the newer models of ThinkPad and the Toshiba Protégé. These models also have fingerprint readers, which are stronger than passwords; of course, no one ever forgets their fingerprints.

08. Disable the Guest Account on your system. Windows 2000 and later systems disable this by default, but it is always a good idea to make sure that this account is indeed disabled. You can further protect yourself by assigning a password to this account and restrict it from logging on.

09. Rename your Administrator account. Now this will not necessarily stop a hacker, but will add an extra step. Some hackers may simply move on to an easier target. Don't rename the account to anything with "Admin" in the name, this is far too obvious. Choose a name that sounds less important.

10. You can also create a dummy Administrator account on your system. Give this account a difficult password and give that account no login privileges or access to anything. Enable auditing if you do this so that you can know if and when anyone tries to hack this account.

Bonus: Configure your computer's Crtl+Alt+Del behavior to prevent displaying the username of the last login. This will make things easier for hackers; they have an easier time with any password guessing attack this way.

If you have an Infrared Port on your laptop, disable it. It is extremely likely that you need or even use this feature on your computer, but it can be used to access your files by other computers nearby. You can disable this port via the BIOS settings, or failing that, cover it up with a piece of electrical tape.

If you are running Windows NT or later (2000, XP), use the far more secure NTFS file system instead of the older FAT32 file system. FAT file systems don't support file-level security, which is like putting out a welcome mat for hackers.

Making certain that your laptop is protected is critical; the reality is that important personal information can be stolen from any computer without precautions. Stealing the information from a laptop is much easier since the computer is moving around and can quickly create a huge disaster.

Web Hosting: PHP, MySQL and ASP.NET

noreply@blogger.com (Tigre de Fogo) — Mon, 19 May 2008 21:30:00 +0000

Web Hosting: PHP, MySQL and ASP.NET
by Arundhati Mahanata

Choosing between LINUX web hosting and Windows hosting is a daunting task. You should know the language of your website, before determining which platform or which type of server you need. Linux hosting is best suitable for a simple HTML site or an ecommerce site or a site with any other programming-database feature created in php-MySql. If your site is in ASP, or ASP.NET, then you need to be on Windows servers.

Now what exactly are ASP.NET, PHP and MySQL web hosting? Let us delve further into these terms.

ASP.NET web hosting: Marketed by Microsoft, ASP.NET is a division of Microsoft's .NET platform and a successor of Active Server Pages (ASP) technology. ASP.NET is a set of Web application development technologies that programmers can use to build dynamic applications, Web sites, and XML Web services.

ASP.NET web hosting cuts down the number of codes and makes building web application much easier. It gives more flexibility to the choice of language by supporting multiple .NET languages. In ASP.NET web hosting, as the source code and HTML are together, the pages are easy to write and maintain. Because of the built-in configuration information, registration of components is not necessary. ASP.NET application is faster and can face a large number of users with a consistency of performance.

PHP web hosting: PHP is a recursive initialism for PHP : Hypertext Preprocessor. PHP is a reflective programming language or a general-purpose server-side scripting language used for web development, i.e. creating dynamic and interactive websites. It can be planted into HTML code. PHP is frequently used together with APACHE on various operating systems mostly LINUX.

PHP acts more like a filter, running on a web server, taking inputs from a stream or file containing text and PHP instructions and displays a different stream of data. PHP is deployable in most operating systems, servers and platforms free of cost.

MySQL web hosting: MySQL is a multi-user, multithreaded computer language designed for management and retrieval of data, database object access control management and database schema creation and modification. It is a SQL database management system with 10 million installations. It is popular for web application, for open-source bug tracking tools and acts as the database component of WAMP, MAMP and LAMP. MySQL is closely related to PHP and Ruby on Rails. Most of the well known sites like Wordpress run on a combination of PHP and MySQL.

Now that you are more familiar with ASP.NET web hosting, PHP and MySQL web hosting, it may prove fruitful in your selection of server type.