Tech-Buzz

Taking control of the cloud

2011-04-10T03:53:00.001-07:00

I have found this white paper about Clouds, Types of clouds, securing the cloud, I thought you may be interested to read it...

http://library.dzone.com/sites/all/files/whitepapers/Taking_Control_of_the_Cloud_0.pdf

Regression vs. Retesting

2011-04-09T12:42:00.000-07:00

Regression vs. Retesting

You must retest fixes to ensure that issues have been resolved before development can progress.

So, retesting is the act of repeating a test to verify that a found defect has been correctly fixed.

Regression testing on the other hand is the act of repeating other tests in 'parallel' areas to ensure that the applied fix or a change of code has not introduced other errors or unexpected behavior.

For example, if an error is detected in a particular file handling routine then it might be corrected

by a simple change of code. If that code, however, is utilised in a number of different places

throughout the software, the effects of such a change could be difficult to anticipate. What appears to be a minor detail could affect a separate module of code elsewhere in the program. A bug fix could in fact be introducing bugs elsewhere.

You would be surprised to learn how common this actually is. In empirical studies it has been estimated that up to 50% of bug fixes actually introduce additional errors in the code. Given this,

it's a wonder that any software project makes its delivery on time.

Better QA processes will reduce this ratio but will never eliminate it. Programmers risk

introducing casual errors every time they place their hands on the keyboard. An inadvertent slip of a key that replaces a full stop with a comma might not be detected for weeks but could have

serious repercussions.

Regression testing attempts to mitigate this problem by assessing the ‘area of impact’ affected by a change or a bug fix to see if it has unintended consequences. It verifies known good behavior after a change.

Hadoop

2011-04-09T12:35:00.001-07:00

What is hadoop?

• Open source software for reliable, scalable, and distributed computing.

• Flexible infrastructure for large scale computation and data processing on a network of commodity hardware.

• The Linux of distributed processing.

Why hadoop?

• Very large distributed file system.

• The data is distributed across data nodes .

• Reliability and availability.

• Files are replicated to handle hardware failure.

• Detects failures and recovers from them.

• Ability to run on cheap hardware.

• Open source flexibility.

• Runs on heterogeneous OS.

• Scalability.

• The number of nodes in a cluster is not constant.

• Parallel processing through MapReduce.

Main components:

• HDFS(Hadoop file system) for storing.

• The Map-Reduce programming model for processing.

Hadoop Distributed File System (HDFS)

• A distributed file system based on GFS, as its shared filesystem.

• Distributed across data servers.

• Data files partitioned into large chunks (64MB), replicated on multiple data nodes.

• NameNode stores metadata information (block locations, directory structure).

Map-Reduce:

• Framework for distributed processing of large data sets.

Amazon DB

2011-04-09T12:29:00.000-07:00

Amazon SimpleDB

• Amazon SimpleDB is a highly available, scalable, and flexible non-relational data store that offloads the work of database administration. Developers simply store and query data items via web services requests, and Amazon SimpleDB does the rest.

• Behind the scenes, Amazon SimpleDB creates and manages multiple geographically distributed replicas of your data automatically to enable high availability and data durability. The service responds to changes in traffic by charging you only for the compute and storage resources actually consumed in serving your requests. You can change your data model on the fly, and data is automatically indexed for you. With Amazon SimpleDB, you can focus on application development without worrying about infrastructure provisioning, high availability, software maintenance, schema and index management, or performance tuning.

Amazon SimpleDB Functionality:

• Build your data set

• Choose a Region for your Domain(s) to optimize for latency, minimize costs, or address regulatory requirements. Amazon SimpleDB is currently available in the US-East (Northern Virginia), US-West (Northern California), and EU (Ireland) Regions.

• Use CreateDomain, DeleteDomain, ListDomains, DomainMetadata to create and manage query domains

• Use Put, Batch Put, & Delete to create and manage the data set within each query domain

• Retrieve your data

• Use GetAttributes to retrieve a specific item

• Use Select to query your data set for items that meet specified criteria

• Pay only for the resources that you consume

Amazon SimpleDB Pricing:

• As your demand grows, you still pay only for what you use. As with other AWS services, there is no minimum fee and no long-term commitment. Also, note that we charge less where our costs are less, thus some prices vary across Geographic Regions. The prices listed are based on the Region in which you establish your Amazon SimpleDB domain(s). Amazon SimpleDB may be used from most countries, so long as payment is made in US Dollars.

• Amazon SimpleDB measures the machine utilization of each request and charges based on the amount of machine capacity used to complete the particular request (SELECT, GET, PUT, etc.), normalized to the hourly capacity of a circa 2007 1.7 GHz Xeon processor.

• Machine Utilization.

• Data Transfer.

• Structured Data Storage.

Amazon Relational Database Service (RDS):

• Amazon Relational Database Service (Amazon RDS) is a web service that makes it easy to set up, operate, and scale a relational database in the cloud. It provides cost-efficient and resizable capacity while managing time-consuming database administration tasks, freeing you up to focus on your applications and business.

• Amazon RDS gives you access to the full capabilities of a familiar MySQL database. This means the code, applications, and tools you already use today with your existing MySQL databases work seamlessly with Amazon RDS. Amazon RDS automatically patches the database software and backs up your database, storing the backups for a user-defined retention period.

• You also benefit from the flexibility of being able to scale the compute resources or storage capacity associated with your relational database instance via a single API call.

• As with all Amazon Web Services, there are no up-front investments required, and you pay only for the resources you use.

RDS Functionality:

• Launch a database instance (DB Instance), selecting the DB Instance class and storage capacity that best meets your needs.

• Select the desired retention period (in number of days) for your automated database backups. Amazon RDS will automatically back up your database during your predefined backup window. For typical workloads, this allows you to restore to any point in time within your retention period, up to the last five minutes. You can also restore from a DB Snapshot, a user-initiated backup that can be run at any time with a simple API call.

• Connect to your DB Instance using your favorite database tool or programming language. Since you have direct access to a full-featured MySQL database, any tool designed for the MySQL engine will work unmodified with Amazon RDS.

• Monitor the compute and storage resource utilization of your DB Instance, for no additional charge, via Amazon CloudWatch. If at any point you need additional capacity, you can scale the compute and storage resources associated with your DB Instance with a simple API call.

• Pay only for the resources you actually consume, based on your DB Instance hours consumed, database storage, backup storage, and data transfer

RDS Pricing:

• Pay only for what you use. There is no minimum fee. Estimate your monthly bill using the AWS Simple Monthly Calculator.

• Amazon RDS DB Instance Pricing

• Provisioned Database Storage

• Backup Storage

• Data Transfer

• Availability Zone Data Transfer

Difference between Data mart and Data Warehouse

2011-04-09T12:24:00.002-07:00

ETL

2011-04-09T12:24:00.001-07:00

An ETL tool is a tool that:

• Extracts data from various data sources (usually legacy)

• Transforms data
• from -> being optimized for transaction
to -> being optimized for reporting and analysis
• synchronizes the data coming from differ databases
• data cleanses to remove errors

• Loads data into a data warehouse

Why use an ETL tool?

• ETL tools save time and money when developing a data
warehouse by removing the need for “hand-coding”.
“Hand Coding” is still the most common way of integrating data
today.

• It requires hours and hours of development and expertise
to create a Business-Intelligence-System.

• It is very difficult for data base administrators to connect
between different brands of databases without using an external
tool.

In the event that databases are altered or new databases need to be integrated, a lot of “hand-coded” work needs to be completely redone.

Most ETL Tool used? Why?

• Informatica and Pentaho have very good products.

• Informatica has a far more extensive range of products, but compared to Pentaho is very expensive.

• Pentaho has proved that it can handle small to large scale systems.

• Pentaho is gaining fast momentum with businesses that would not have considered using open source products before.

Data processing

2011-04-09T12:20:00.000-07:00

Data processing types:

Transactional: High-volume and easy-processing collections of knowledge that generate by organizations a day.

Analytical: Analysis of accumulated information frequently by end users; additionally remarked as business intelligence, includes decision call support systems (DSSs), enterprise info systems, internet applications, querying, and alternative end-user activities.

Multidimensional information Model:

• The third-dimensional information model is an integral a part of On-Line Analytical process, or OLAP. as a result of OLAP is on-line, it should offer answers quickly.

• The third-dimensional information model is meant to unravel complicated queries in real time.

• The third-dimensional information model is vital as a result of it enforces simplicity.

• The central attraction of the dimensional model of a business is its simplicity.... that simplicity is that the basic key that permits users to grasp databases, and permits software package to navigate databases expeditiously.

• The relative implementation of the third-dimensional information model is usually a star schema,or a snowflake schema.

Star schema:

• The star schema consists of 1 or additional truth tables and one or additional dimension tables that ar connected through foreign keys.

• dimensions ar pessimistic with every dimension being diagrammatic by one table

Snowflake schema:

• a kind of star schema within which the dimension tables ar partially or totally normalized.

• Dimensions ar normalized into multiple connected tables.

Data warehouse:

• A DW could be a subject homeward, integrated, time variant and non volatile assortment of knowledge in support of management’s deciding} process. {a information|a knowledge|an information} warehouse is that the main repository of the organization's historical data, its company memory

• these days organizations use DW to store analytical information so as to put strategic info within the hands of call manufacturers to assist productivity and empower users for creating higher choices, resulting in larger competitive advantage.

Data retail store definition:

• information marts ar analytical information stores designed to specialize in specific business functions for a selected community among a company. information marts ar typically derived from subsets {of information|of knowledge|of information} in an exceedingly data warehouse.

Data retail store types:

1-Dependent information Marts:

Allows you to unite your organization's information in one information warehouse. this offers you the standard blessings of centralization.

2-Independent information Marts

Is created while not the employment of a central information warehouse. this might be fascinating for smaller teams among a company.

3-Hybrid information Marts

Allows you to mix input from sources apart from an information warehouse.

RDBMS Meets the Cloud

2011-04-08T13:43:00.000-07:00

• The traditional relational database can be a poor fit in these cloud environments. The promise of the cloud is that you can increase computing resources by allocating additional virtual machines.

• As a result, cloud providers offer simpler, nonrelational databases that can provide elastic on-demand scalability. The major offerings are:

• SimpleDB within Amazon AWS

• BigTable within Google App Engine

• Microsoft’s Azure Table Services and SQL Data Services

• These cloud databases differ in implementation detail, but share common core features:

• A hierarchical structure resembling a B-tree index or hash table. Rapid lookup via a single key value is provided.

• Flexible. Each “row” often can contain different “columns,” and columns may have multiple values or include a more complex embedded structure.

• Automatic geo-redundancy. Elements stored in the database are guaranteed to be replicated across multiple data centers.

• Automatic partitioning across multiple hosts and automatic scale-out as the size of – or demand on – the data store exceeds the capability of a single host.

• However, these databases are missing many of the features we’ve come to expect in a relational solution:

• Joins and complex queries must be implemented in procedural code.

• Transactions are not supported. You can’t create a set of changes that must succeed or fail as a single unit.

• “Eventual” consistency. When you make a change to a data item, it will be visible eventually, but not immediately, in all locations where a copy of that data is maintained.

• Will cloud databases disrupt the RDBMS market? Probably not. But the cloud environments available from Amazon, Google and Microsoft offer significant advantages over traditional hosting or in-house hardware models. Applications that exploit the cloud will find the scalability and zero-maintenance models of these cloud databases appealing. As these cloud applications emerge into the mainstream, the cloud database probably will establish a permanent and successful segment of the database taxonomy.

Comparison between DBMS

2011-04-08T13:35:00.000-07:00

Many of you may asked this question "What are the differences between all of the different types of SQL? I hear of PostgreSQL, SQLite, MySQL, SQL, .... What are the differences between them?"

here you will find a comparison between DBMS like :

• Oracle.

• Mysql.

• Microsoft SQL Server .

• Postgresql.

• Hbase.

• DB2.

• Teradata.

Transparency

2011-04-08T13:27:00.000-07:00

Distribution Transparency

• Distribution transparency allows user to perceive database as single, logical entity.

• If DDBMS exhibits distribution transparency, user does not need to know:

• Data is fragmented (fragmentation transparency),.

• Location of data items (location transparency).

• Otherwise call this local mapping transparency.

• With replication transparency, user is unaware of replication of fragments.

Naming Transparency:

• Each item in a DDB must have a unique name.

• DDBMS must ensure that no two sites create a database object with same name.

• One solution is to create central name server. However, this results in:

• loss of some local autonomy;

• central site may become a bottleneck;

• low availability; if the central site fails, remaining sites cannot create any new objects.

• Alternative solution - prefix object with identifier of site that created it.

• For example, Branch created at site S₁ might be named S1.BRANCH.

• Also need to identify each fragment and its copies.

• Thus, copy 2 of fragment 3 of Branch created at site S₁ might be referred to as S1.BRANCH.F3.C2.

• However, this results in loss of distribution transparency.

• An approach that resolves these problems uses aliases for each database object.

• Thus, S1.BRANCH.F3.C2 might be known as LocalBranch by user at site S₁.

• DDBMS has task of mapping an alias to appropriate database object.

Transaction Transparency:

• Ensures that all distributed transactions maintain distributed database’s integrity and consistency.

• Distributed transaction accesses data stored at more than one location.

• Each transaction is divided into number of subtransactions, one for each site that has to be accessed.

• DDBMS must ensure the indivisibility of both the global transaction and each of the subtransactions.

Concurrency Transparency:

• All transactions must execute independently and be logically consistent with results obtained if transactions executed one at a time, in some arbitrary serial order.

• Same fundamental principles as for centralized DBMS.

• DDBMS must ensure both global and local transactions do not interfere with each other.

• Similarly, DDBMS must ensure consistency of all subtransactions of global transaction.

Performance Transparency:

• DDBMS must perform as if it were a centralized DBMS.

• DDBMS should not suffer any performance degradation due to distributed architecture.

• DDBMS should determine most cost-effective strategy to execute a request.

Distributed Transactions

2011-04-08T13:26:00.000-07:00

Distributed Transactions

• A distributed transaction is a transaction that updates data on two or more networked computer systems. Distributed transactions extend the benefits of transactions to applications that must update distributed data. Implementing robust distributed applications is difficult because these applications are subject to multiple failures, including failure of the client, the server, and the network connection between the client and server. In the absence of distributed transactions, the application program itself must detect and recover from these failures.

• For distributed transactions, each computer has a local transaction manager. When a transaction does work at multiple computers, the transaction managers interact with other transaction managers via either a superior or subordinate relationship. These relationships are relevant only for a particular transaction.

• Each transaction manager performs all the enlistment, prepare, commit, and abort calls for its enlisted resource managers (usually those that reside on that particular computer). Resource managers manage persistent or durable data and work in cooperation with the DTC to guarantee atomicity and isolation to an application.

Distributed update propagation

• Update propagation in a distributed database is problematic because of the fact that there may be more than one copy of a piece of data because of replication, and data may be split up because of partitioning. Any updates to data performed by any user must be propagated to all copies throughout the database. The use of snapshots is one technique for implementing this.

Distributed concurrency control

• Concurrency control in distributed databases can be done in several ways. Locking and timestamping are two techniques which can be used, but timestamping is generally preferred.

• The problems of concurrency control in a distributed DBMS are more severe than in a centralized DBMS because of the fact that data may be replicated and partitioned. If a user wants unique access to a piece of data, for example to perform an update or a read, the DBMS must be able to guarantee unique access to that data, which is difficult if there are copies throughout the sites in the distributed database.

Distributed Queries Optimization

• In a distributed database the optimization of queries by the DBMS itself is critical to the efficient performance of the overall system. Query optimization must take into account the extra communication costs of moving data from site to site, but can use whatever replicated copies of data are closest, to execute a query. Thus it is a more complex operation than query optimization in centralized databases.

Query optimization overview

• Query optimization is essential if a DBMS is to achieve acceptable performance and efficiency. Relational database systems based on the relational model and relational algebra have the strength that their relational expressions are at a sufficiently high level so query optimization is feasible in the first place; in non-relational systems, user requests are low level and optimization is done manually by the user - the system cannot help. Hence systems which implement optimization have several advantages over systems that do not.

• The optimization process itself involves several stages, which involves the implementation of the relational operators. A different approach to query optimization, called semantic optimization has recently been suggested.

• This technique may be used in combination with the other optimization techniques and uses constraints specified on the database schema. Consider the SQL query:

SELECT E.LNAME FROM EMPLOYEE E M WHERE E.SSN = M.SSN AND E.SALARY > M.SALARY This query retrieves the names of employees who earn more than their supervisors.

• Suppose we had a constraint on the database schema that states that no employee can earn more than their supervisor. If the semantic query optimizer checks for the existence of this constraint, then it need not execute the query at all. This may save considerable time if the checking for constraints can be done efficiently; however, searching through many constraints to find ones applicable to a given query can also be quite time consuming.

Timestamping

• Timestamping is a method of concurrency control where basically, all transactions are given a timestamp or unique date/time/site combination and the database management system uses one of a number of protocols to schedule transactions which require access to the same piece of data.

• While more complex to implement than locking, timestamping does avoid deadlock occurring by avoiding it in the first place

Data Fragmentation &Allocation

2011-04-08T13:20:00.000-07:00

Data Fragmentation

Relation may be divided into a number of sub-relations, which are then distributed.

Benefits:

Usage

• Applications work with views rather than entire relations.

Efficiency

• Data is stored close to where it is most frequently used.

• Data that is not needed by local applications is not stored.

Parallelism

• With fragments as unit of distribution, transaction can be divided into several sub queries that operate on fragments.

Security

• Data not required by local applications is not stored and so not available to unauthorized users.

Types of Fragmentation

• Four types of fragmentation:

• Horizontal.

• Vertical.

• Mixed.

• Derived.

• Other possibility is no fragmentation:

• If relation is small and not updated frequently, may be better not to fragment relation.

Data Allocation:

• Each fragment is stored at site with “optimal” distribution

• Four alternative strategies regarding placement of data:

• Centralized.

• Partitioned (or Fragmented).

• Complete Replication,

• Selective Replication.

• Centralized

• Consists of single database and DBMS stored at one site with users distributed across the network.

• Partitioned

• Database partitioned into disjoint fragments, each fragment assigned to one site.

• Complete Replication

• Consists of maintaining complete copy of database at each site.

• Selective Replication

• Combination of partitioning, replication, and centralization.

Distributed database

2011-04-08T13:15:00.000-07:00

A logically reticulated collection of shared information (and an outline of this data), physically distributed over a network.

A logically reticulated collection of shared information (and an outline of this data), physically distributed over a network.
Read more at http://smallseotools.com/article-rewriter/#XTJdjtUQ9LrUrlbo.99

Distributed software system

Software system that allows the management of the distributed information and makes the distribution clear to users.
Distributed information system (DDBS) = DDB + DDBMS

Distributed database features:

• information hold on at variety of web sites, every web site logically single processor

• Sites square measure interconnected by a network instead of a digital computer configuration

• DDB is logically one information (although every web site may be a information site)

• DDBMS has full practicality of a software system

• To the user, the distributed information system ought to seem specifically sort of a non-distributed information system.

Distributed database advantages:

• Reduced Communication Overhead : Most information access is native, less costly and performs higher.

• Improved process Power : rather than one server handling the complete information, we tend to currently have a group of machines handling a similar information.

• Removal of Reliance on a Central web site

• Expandability

• native autonomy

The information is brought nearer to its users. this will impact a cultural modification because it permits doubtless bigger management over native information.

Distributed database disadvantages:

• complexness (greater potential for bugs in software)

• price (software development may be far more complicated and thus pricey. Also, exchange of messages and extra computations involve increased overheads)

• distribution of management (no single information administrator controls the DDB)

• security (since the system is distributed the possibilities of security lapses square measure greater)

• troublesome to alter (since all sites have management of their own sites)

• lack of expertise (enough expertise isn't on the market in developing distributed systems)

DDBMS rules:

No reliance on a central web site
Continuous operation
Location independence
Fragmentation independence
Replication independence
Distributed question independence
Distributed dealings process
Hardware independence
OS independence
Network independence
information independence

Distributed database Issues:

information Fragmentation
information Allocation
information Replication
Distributed Catalogue Management
Distributed Transactions
Distributed Queries optimisation
Distributed update propagation
Distributed concurrency management

Parallel DBMS Concept

2011-04-08T06:33:00.000-07:00

• A database management system that is implemented on a tightly coupled multiprocessor.

• seeks to improve performance through parallelization of various operations, such as data loading, index building and query evaluating।
WHY DO WE NEED it?

• More and More Data!

•We have databases that hold a high amount of data, in the order of 1012 bytes: 10,000,000,000,000 bytes!

• Faster and Faster Access!

• We have data applications that need to process data at very high speeds: 10,000s transactions per second!
SINGLE-PROCESSOR DBMS AREN’T UP TO THE JOB!

Database Problem

2011-04-08T06:28:00.000-07:00

•Large volume of data

-> use disk and large main memory

• I/O bottleneck (or memory access bottleneck)

->Speed(disk) << speed(RAM) <

• Predictions

->processor speed growth : 50 % per year

->DRAM capacity growth : 4x every three years

->Disk throughput : 2x in the last ten years

Benefits of Developing Website in PHP

2011-03-05T14:40:00.000-08:00

PHP is considered a server side scripting language, as against JavaScript, that is a client aspect language, It is one amongst the foremost widespread languages utilized in internet development nowadays.

Despite the actual fact that nearly each internet language for the online has its shortcomings, there ar varied edges to mistreatment PHP in internet development.

So here ar some not all edges in mistreatment the PHP language in internet development:

#1: freed from price
    PHP is free of charge and at no cost to use. It will be effortlessly downloaded and spread, you do not need compensating. it's utilized by immeasurable individuals and enormous cluster of internet designers and developers round the world. there's no restriction of what you are doing or do not with the Language.

#2 – Capable
      It will be wont to style any style of web site and may handle websites with plenty of traffic. Facebook, Twitter, Wikipedia and plenty of alternative terribly wide visited websites use it as their framework. and since it\'s server-side scripting, it will do something that alternative CGI programs will do.

#3 – Easy
    PHP is by and enormous individual responsive, because it is untroubled and easy to find out and perceive than alternative high level programming languages for example C, C++, ASP or ASP.net.

#4 –decreases payment bills
    PHP decreases payment bills of your server at constant time likewise as running on your Windows based mostly server. several of PHP developers and business data processor style corporations ar by suggests that of PHP currently on a daily basis.

#5 – quicker Developments
    Dispensation pace of PHP is subdued faster than alternative programming languages. PHP pages take a lesser quantity of your time to load.

#6 – Platform freelance
paramount a part of PHP is that it will be with no bother run on all major in operation systems like mack OS, windows, Linux etc. And this is often one amongst the explanations that the nice businesses choose PHP for his or her company data processor style, as they will effortlessly incorporate their existing internet application with PHP.

    #8 – Secure
it\'s multiple layers of security to stop threats and malicious attacks.

Top 5 Principles of Effective E-Commerce Website Designing

2011-03-05T14:23:00.000-08:00

Websites play an important role in E-Commerce business. As it is the only medium of interaction between the sellers and online shoppers, so it has to be carefully designed. E-Commerce websites are designed in order to accomplish the commercial needs. Internet surfers have become very smart and they can easily differentiate between good and poor website. In order to maximize the chances of success it’s very important during the design phase to carefully consider the following principles of effective E-Commerce website design.

User-Friendly Navigation: The navigation pattern in an E-Commerce website should be very simple and easy to understand. Since online shoppers cannot feel and touch the online store and its products. So, let your audience navigate through the website easily and you cater to their needs. Make use of breadcrumbs to make an enhanced and easy search process for the visitors.
Be Creative but Don’t Sound Absurd: Being creative is really good for designing an E-Commerce website. In order to get quality traffic, it is very necessary to make your website attractive and user-friendly. But it should not seem as if you are selling design and not the products. It should be designed in a way that all the common questions and objections are answered. Creativity is something which cannot be bought therefore, if you are really concerned about your E-Commerce web designing then, you can always hire dedicated web designers who provide professional website design services.
Security: You need to assure the shoppers that their private (contact and financial) details would not be shared to any third party. Security is an issue that is paramount to your customers. So, make sure your online payment processing is secure. Failure to do this would result lost customers, which in turn would lead loss in sales.
Instant Response: To make E-Commerce website more attractive, designers often make use of flash files and heavy HTML coding. Bigger flash files take more time to get loaded. Internet surfers are very impatient and need an instant response to their action. So, if the website or the images are taking too much of time to get loaded, the shoppers might get annoyed. Also, remember that an annoyed customer is a lost customer.
Quick Solution to Customer Queries: Customers might have some kind of queries in their mind while shopping online. Therefore, it is very important to provide customer service online that would actually resolve customer queries and help facilitating the online shopping.

All the above aspects help you to build a long term relationship with your customers and an excellence in all these will help you bring your customers back on your website.

About Author:
PixelCrayons is an industry leader in providing bespoke Ecommerce Web Design solutions. Here, you can hire dedicated Magento Designer and OsCommerce Designer on hourly basis.

Article source: http://www.articleszoom.com/top-5-principles-of-effective-e-commerce-website-designing/

Factors to Consider in Buying a Portable Printer for Laptop

2011-03-05T14:18:00.000-08:00

A portable printer for laptop is a very helpful device for people who are always on the road for business purposes. Portable printers give busy people the chance to print important papers wherever they are so it really helps a lot in multi-tasking and conserving time. Most of the types of these devices weigh only a few pounds so they are not a hassle and can be brought in any type of traveling vessel. Nowadays, there are a lot of portable printers available in the market. Unfortunately, the availability of these diverse brands is also the reason that makes it hard to choose for the right one to use.

In choosing a portable printer for laptop, there are a couple of questions to ask yourself to help you narrow down your choices. The first one is the features of the printer which you will need. Will you primarily use it to print black and white documents? Or will you mainly use it for photo printing and other production of colored documents? Another important question to ask is whether you want a wireless or usb-connected printer. Usb-connected printers are less costly but the wireless ones are faster and easier to connect.

The price of mobile laptop printers range from $250 to $400 dollars. As compared to the traditional bulky printers, this price is considerably lower and more affordable for those who are working on a tight budget. At the same time, people do not need to worry about lugging a heavy device for their business errands because these devices weigh no more than 5 lbs. This is very convenient for those who are always traveling through flights where additional weight in baggage usually means additional payment. Moreover, portable printers also do not need to be constantly connected to a power source because most are battery-powered.

Article source: http://www.articleszoom.com/factors-to-consider-in-buying-a-portable-printer-for-laptop/

Centralized Database

2011-03-01T12:06:00.001-08:00

A Centralized database is an unionised collection knowledge|of knowledge} or data that is found and maintained in one location from numerous points. it's totally different from a distributed database since all information is mostly placed in one place from multiple places.

The advantages of the information being centralised

easier to organize, edit, update and back-up the info

less information duplication - information is just entered once however are often accessed by several users

information integrity - because information is hold on once totally different information isn't any longer control in numerous databases in numerous departments round the organisation

The impact on an organisation of employing a centralised information are often large. It will greatly increase productivity and potency.

For example, in associate degree ordering system, a client might phone orders and provides notice that their address has modified; once the order operator changes that address it's been changed across the system. If the accounts department then would like to send an announcement to the client they're going to have the customer's new address.

Cloud Computing Buzz Word

2011-02-24T17:09:00.000-08:00

As the 1st post in this site we are going to point out a really famed Buzz Word "Cloud computing".
Cloud systems are, unlike e.g. grid computing, not driven by research 1st then being obsessed by business, however instead originates directly from industrial necessities and solutions.

therefore what's cloud computing?
No one might precisely say what's cloud computing however normally we tend to might say it's AN elastic execution surroundings of resources involving multiple stakeholders and providing a metered service at multiple granularities for a given level of quality (of service).

I think this picture show us a lot about cloud systems

Now who have any other description, clarification ,etc for cloud please share with us.