LUS@N Computer Consultancy Service

How to Protect Your Eyes When Using a Computer

2010-12-01T21:23:00.000-08:00

Since the majority of us spend hours in front of a computer monitor, it is good practice to protect your eyes from potential damage. Keep in mind that the following recommendations apply only to properly setting up your workstation to best protect your eyes and do not address other ergonomic needs related to working in front of a computer.

Instructions

1. Taking Proper Care of Your Eyes.

Take five-minute breaks every hour by looking off into the distance and looking away from the computer monitor. Just close your eyes for a few minutes when your work requires prolonged data input into the computer.

2. Keeping Proper Distance and Other Safety Measures.

Keep the distance of the monitor from your eyes between 16 to 30 inches. Most people find a distance of 20 to 26 inches comfortable. Make sure that the top of the monitor is at a level slightly below the horizontal eye level. Tilt the top of the monitor away from you at a 10- to 20-degree angle. Most monitors are provided with tiltable display screens, which enable you to tilt the monitor to create an optimum viewing angle. Keep your screen free of dust and fingerprints. Use an adjustable chair that enables you to sit at a proper angle and distance from your computer monitor screen. Use document holders to secure any reading material or reference material, if your work involves prolonged data entry. Place the document holders close to the monitor and at the same distance from your eyes as your monitor. This enables your eyes to remain focused as they look from the monitor to the reading material. Use a work surface whose height is 26 inches from the ground. Keep the distance from the front of your chair to the hollow of your knee between 2 to 4 inches. Use a character size that is visible. The character size is an important factor since it determines the distance at which the user prefers to view the monitor.

3. Changing the Appearance of the Text Fonts on Your Computer Screen.

Point your cursor anywhere on your desktop and right click on Properties. The Display Properties window appears. Click the Appearance tab on the Display Properties window.
Go to the Font Size pull-down menu and choose either "Large Fonts" or "Extra Large Fonts" instead of the "Normal" font that has already been pre-selected by default. That is, if you are working on a Windows XP system. Once you have made a choice, you will see a sample of what you have chosen in the upper part of the Display Properties window. Choose what is comfortable for your eyes. Click on the Apply button. Close the Display Properties window.

4. Ensuring Proper Lighting.

Use fluorescent tubes to achieve lower illumination levels. Higher illumination levels wash out the image on the screen. Illumination levels refer to the amount of light falling on a surface measured in lux or foot candles (metric and English systems of measurement respectively). Provide supplementary task lighting through lamps. Task lighting allows workers to adjust the illumination level according to their own preferences, if the illumination level is below the suggested ideal of 50 foot candles.

5. Ensuring Proper Lighting by Adjusting the Contrast.

Contrast is the difference in luminance between two areas (the task area and the background area). Prevent excessive contrast within the visual field and reduce the contrast to acceptable limits by avoiding extremely dark or bright surfaces. The primary reason for this is that vision problems could arise and viewing becomes difficult when there is high contrast between task and adjacent surroundings. A good display screen also has separate contrast and brightness controls. Adjust the brightness of the background in relation to the characters by adjusting the contrast controls. Control the amount of light emitted from the characters themselves by adjusting the brightness controls.

6. Ensuring Proper Lighting in Your Work Environment To Prevent Glare.

Glare is caused by non-uniform distribution of luminance within your visual field, as well as bright luminaires or windows. You can prevent glare by reorienting your work station and moving the sources of glare out of your line of sight. Cover windows with Venetian blinds, draperies, shades or filters to reduce glare from sunlight or the luminaires in your work environment. Use panels to block the intensity of light, thereby reducing glare. Adjust the computer's contrast knob to change the brightness of the screen and characters, which will also reduce glare. Position the screen at right angles to the source of light. Avoid wearing bright clothes which may cause a glare by causing a reflection on the screen. Cover your monitor ith an anti-glare screen.

7. Ensuring Proper Lighting in Your Work Environment to Prevent Reflective Glare.

When a worker can see a light on the surface of his or her screen, this is the case of reflective glare. This glare can also be seen on smoothly polished desk tops. The sources of reflected glare can be windows, reflective walls, luminaires or reflective clothing. You can control the reflective glare by the methods suggested in each of the steps below. Reduce the intensity of light source by providing louvres for luminaires, by covering windows or by choosing appropriate height panels. Provide a matte or flat finish on furniture equipment or walls. Tilt the monitor to remove the reflection away from your line of vision. Tilting features are now included in most terminals. Cover the screen with an etched surface or with different types of filters.

8. Rearranging the Office to Reduce Lighting Problems.

Position the workstations between rows of luminaires. Place the workstations away from the windows. Place all workstations parallel to the windows. Use panels to block light.

9. Selecting Video Display Colors to Avoid a Vision Problem Called McCullough Effect.

When the color of the video display screen is green, some users see pink afterimages. This is an unusual phenomenon called the McCullough Effect. The condition causes people who use computers for hours to see a pinkish fringe around certain images. Although this is a harmless afterimage, the afterimage is created when the retinal nerve cells that perceive the color green become saturated and the color red appears instead. Choose video displays that are not green in color to prevent this vision problem from occurring. Remember: The contrast between the characters on the screen and the screen background should be high.

Adapting To Office 2007

2010-06-12T20:45:00.000-07:00

Most Office 2007 programs sport a dramatically different interface, as well as new file formats. Here are some tips on how to adapt.
Users can download the Office 2007 Compatibility Pack to install over Office 2000, Office XP, or Office 2003.Microsoft has developed a set of file converters to allow users with older Office versions to open, edit, and save files saved in Office 2007’s new file format. Microsoft has add-ins available to add "save as PDF" functionality directly to Office 2007 programs, as well as a set of file converters to allow users with Office 2003 and earlier to open and save files in the new compressed file formats. That's quite handy instead of upgrading the entire office at once!
The first thing everyone notices about Office 2007 is the new interface. Gone are the traditional File, Edit, View, Tools menus. In their place we have The Ribbon. The ribbon is basically a tabbed set of toolbars. Three rows high, it groups related items like font settings, styles, page setup options, and so on, on tabs named things like Home, Insert, and Page Layout, so users can more easily find them. In addition settings are "live," for instance as one moves up and down the list of font sizes, the words actually change size on the page.

CLICK HERE TO LEARN MORE..

Something About UPS

2010-06-12T20:20:00.000-07:00

A UPS generally protects a computer against four different power problems like:

Voltage surges and spikes - Times when the voltage on the line is greater than it should be.

Voltage sags - Times when the voltage on the line is less than it should be.

Total power failure - Times when a line goes down or a fuse blows somewhere on the grid or in the building.

Frequency differences - Times when the power is oscillating at something other than 60 Hertz

There are two common systems in use today: standby UPS and continuous UPS. A standby UPS runs the computer off of the normal utility power until it detects a problem. At that point, it very quickly (in five milliseconds or less) turns on a power inverter and runs the computer off of the UPS's battery. A power inverter simply turns the DC power delivered by the battery into 120/240-volt, 60-Hertz AC power.

In a continuous UPS, the computer is always running off of battery power and the battery is continuously being recharged. You could fairly easily build a continuous UPS yourself with a largish battery charger, a battery and a power inverter. The battery charger continuously produces DC power, which the inverter continuously turns back into 120/240-volt AC power. If the power fails, the battery provides power to the inverter. There is no switch-over time in a continuous UPS. This setup provides a very stable source of power.

Standby UPS systems are far more common for home or small-business use because they tend to cost about half as much as a continuous system. Continuous systems provide extremely clean, stable power, so they tend to be used in server rooms and mission critical applications.

What Not to Connect to a UPS

Never connect a laser printer to a small UPS. When the fuser element heats up, a printer draws a large amount of current, more than a small or even medium UPS can provide. If this happens, you will trip the circuit breaker in the UPS. If you would like your new laser printer to be protected, only the larger UPS models will be able to provide the power required.

A UPS beeps to warn the user of a power problem or dead battery. Occasional random beeping typically indicates a temporary over- or under-voltage condition. If this happens often have your power checked out.

Update: UPS batteries typically last three to five years, depending in part on how often the battery is used.

What's New In Windows 7

2010-01-24T23:26:00.000-08:00

Click here to know What's New In Windows 7?

Be perfect to use Microsoft Word 2007

2009-12-19T23:50:00.000-08:00

Please click on the link below which you want to learn

Lesson 1: Getting Familiar with Microsoft Word 2007 for Windows

Lesson 2: Microsoft Word 2007 Basic Features

Lesson 3: More Basic Features

Lesson 4: Formatting Paragraphs and Working with Styles

Lesson 5: Adding Bullets and Numbers, Undoing and Redoing, Setting Page Layouts and Printing Documents

तपाईंको कम्प्युटरको गती(speed)बढाउने उपायहरु(Tips).

2009-12-19T23:48:00.000-08:00

१. सर्बप्रथम कम्प्युटर खोल्ने बित्तिकै कुनै पनि Application चाँड चांडै नखोल्नुस् , पहिला राम्रो सँग PC लाई Bootup हुन दिनुस् ।

२. कुनैपनि Application बन्द गरी सके पछि आफ्नो Desktop लाई एक पल्ट Refresh गर्नुस् यसले तपाईंको कम्प्युटरको Ram मा जम्मा भएको Unused फाइलहरु Remove हुन्छ ।

३. आफ्नो कम्प्युटरमा सके सम्म Wallpaper को Use नै नगर्नुस् र यदि गर्नुनै छ भने ठुलो साइजको Image लाई Use नगर्नुस् ।

४. आफ्नो Desktop मा धेरै Unnessesary Shortcut हरुलाई नराख्नुस् र सके सम्म Desktop लाई Clean नै राख् नुस् । Desktop मा फोटो तथा Music को फाइलहरुलाई पनि Save नगर्नुस् ।

५. RecycleBin लाई बेला बेलामा Empty गरी राख् नुस् । तपाईंले Delete गर्नु भएको फाइलहरु RecycleBin मा जम्मा भई राखेको हुन्छ र तपाईंको कम्प्युटरको Harddrive को ठाउँ यसले लीइ राखेको हुन्छ ।

६. temporary internet files लाई बेला बेलामा Delete गरी राखनुस् ।

७. आफ्नो कम्प्युटर लाई प्रत्येक २ महिनामा Defragment गर्नुस् । यसले तपाईंको कम्प्युटरको Harddrive मा धेरै खाली ठाउँ बनाउछ र Program हरु Fast चल्छन ।

८. आफ्नो कम्प्युटर लाई जहिले पनि २ वा २ भन्दा बढीमा partitions गर्नुस् र सके सम्म Software हरुलाई दोस्रो वा तेस्रो Drive मा Instal गर्नुस् । सके सम्म C Drive लाई खाली नै राख् नुस् ।

९. जब तपाईंले नयाँ Software हरु Instal गर्नु हुन्छ त्यो Software को Tray Icon लाई Disable गर्नुस् , यि Icon हरुले तपाईंको कम्प्युटरको RAM को Use गरी राखेका हुन्छन र कम्प्युटर Slow हुन सक्छ र Software का starting the application automatically Option लाई पनि Disable गर्न नभुल्नु होला । यस्ता Option हरुलाई तपाइले software हरु Instal गरी सके पछि उक्त Software को Tools मा गएर पनि Disable गर्न सक्नु हुन्छ ।

१०. आफ्नो कम्प्युटर लाई धुलो बाट पनि सके सम्म बचाउनुस् , किन भने धुलोले तपाईंको कम्प्युटरका Cooling Fan हरुलाई जाम गरी दिन सक्छ यसले कम्प्युटर अनावश्यक रुपमा तातो हुन सक्छ र कम्प्युटर Slow Down हुन सक्छ ।"यि १० वटा साधारण Tips हरुलाई बिचार पुर्‍याउनु भयो भने तपाईंको कम्प्युटर तुलनात्मक रुपमा पहिले भन्दा धेरै Speed मा चल्न सक्छ ।"

हजुरको कम्प्युटरको सुरक्षाको लागि उपायहरु(Tips).

2009-12-19T23:40:00.000-08:00

१) सधैं "anti-virus software" को प्रयोग गर्नुस् र यसलाई सधैं Up to Date गर्नुस् । "तपाईं यो सुनिस्चित गर्नुस् कि तपाईं सँग राम्रो anti-virus software छ र यस्ले तपाईंको कम्प्युटरलाई virus बिरुद्द सुरक्षा गर्छ । उक्त anti-virus Software लाई सधैं Up to Date राख् ने गर्नुस् । Virus दैनिक जसो फरक फरक बन्दै जान्छन त्यसैले तपाईंले आफ्नो anti-virus software लाई Up Date गरी राख् नु जरुरी छ । जति धेरै तपाईंले यसलाई Up to Date राख् नु हुन्छ त्यती राम्रो , नभए हप्ता को १ पल्ट अबस्य Up to Date गर्नुस् ।"
२) आफ्नो e-mail मा आएका mail हरुलाई नहेरी नबुझी झत्तै कहिले पनि नखोल्नुस् । शँका लागेका mail हरु कहिले पनि नखोल्नुस् Even तपाईंले चिनेको मान्छेले पठाएको भए पनि..." यो एउटा साधारण नियम नै हो कि यदि तपाईं कसैलाई चिन्नु हुन्न भने त्यो मान्छेले पठाएको mail खोल्नु तपाईंलाई जरुरी छैन र त्यो mail सँग जोडीएको कुनै Attachment पनि । यदि तपाईंलाई शँका लागेका यस्ता कुनै mail आएको छ भने त्यसलाई Delete गरी दिनु नै राम्रो हुन्छ न कि के हो एक चोटि खोली हेरु भनी खोल्नु । यदि तपाईंलाई खोल्नु नै छ भने पनि पहिला त्यो फाइललाई कम्प्युटरमा Save गर्नुस् र आफ्नो Anti-virus Software ले virus check गरेर मात्र खोल्नुस् तर यो पनि तपाईंको कम्प्युटरको लागि risk हुन सक्छ । साथै तपाईंलाई एउटै message एउटै नाम बाट धेरै आएको छ भने पनि तपाइ साबधान हुनुस् ।"
३) आफ्नो कम्प्युटरमा तपाईंले नचाहेर प्रवेस गर्नेलाई रोक्ने सुरक्षित ईन्टरनेट Firewalls लाई activate गर्नुस् । " तपाईंको कम्प्युटरमा भएको Firewalls system लाई active राख् नुस् । यसले तपाईंको कम्प्युटर र बाँकी दुनियाँको बिच सुरक्षा पर्खालको काम गर्छ । यसले तपाईंको कम्प्युटरको software र Hardware को एकै चोटि रक्षा गर्ने काम गर्छ । यसले तुलनात्मक रुपमा अनधाक्रित र खराब Data हरु बिरुद्द सुरक्षाको दिन्छ ।"
४) सके सम्म guess गर्न गार्हो Password को प्रयोग गर्नुस् । " जस्तै capital letter र small latter को mix , कुनै symbol को बिचमा प्रयोग अनि अंक को प्रयोग । र यो पनि नभुल्नुस् कि तपाईंको password कमसे काम ८ ओटा भन्दा कम नहोस् , आफ्नो password लाई regularly change गरी राख् नुस् at least ९० दिन भित्रमा र आफ्नो password कसै सँग पनि Share नगर्नुस् ।"
५) आफ्नो कम्प्युटरको महत्वपूर्ण Data हरुलाई Backup को रुपमा CD मा राख् ने गर्नुस् । " अनुभव प्राप्त कम्प्युटर अपरेटरले सधैं आफ्नो महत्वपूर्ण Data हरुलाई Backup को रुपमा Disk वा CD हरुमा राखेका हुन्छन । यस्तो गर्ने बानिले तपाईंले कहिले काही आफ्नो कम्प्युटरका Data हरु loss भएको खण्डमा धेरै काम दिन सक्छ । तपाईंको कम्प्युटरका Data हरु कुनै बेला पनि Damage हुन सक्छ त्यसैले बेलामै तयार रहनुस् ।"
६) आफ्नो कम्प्युटरलाई कहिले पनि Sharing नगर्नुस् " तपाईंको कम्प्युटरलाई अरु कम्प्युटर सँग network वा Internet बाट sharing नगर्नुस् , यसबाट पनि तपाईंको कम्प्युटरमा virus सर्न सक्ने धेरै Chance हुन्छ त्यसैले जरुरी नभए सम्म sharing mode लाई Turn Off नै राख् नुस् । आफ्नो operating system लाई check गर्नुस् कि कसरी यसलाई disible गर्न सकिन्छ र कहिले पनि कुनै अपरिचित सँग आफ्नो कम्प्युटर लाई share नगर्नुस् ।"
७) Internet connection लाई disconnect गर्नुस् यदि use भएको छैन भने " यो याद राख्नुस् कि Digital Highway को २ वटा बाटो हुन्छ , तपाईंले कुनै Data पठाउनु हुन्छ र पाउनु हुन्छ , जहिले पनि Sent र Receive को नियम लागु हुन्छ । यदि तपाईं online मा हुनु हुन्छ र तपाईं सँग Anti-virus सफ्टवेर छैन र Firewalls पनि active छैन भने अरु कुनै दोस्रो मान्छेले तपाईंको कम्प्युटरमा virus infect गर्न सक्छ । त्यसैले यदि तपाईंलाई आवश्यकता छैन भने Internet connection लाई Disconnect गर्नुस् ।"
८) आफ्नो कम्प्युटरको security system लाई बेला बेलामा check गरी राख् नुस् । " प्रोग्राम र opereting system को धेरै महत्वपूर्ण Value छ तपाईंको life सजिलो गराउनमा तर तपाईंलाई टाढा रहनु छ hackers र viruses सँग र यिनिहरुले तपाईंको यि नै महत्वपूर्ण अङमा आक्रमण गर्न्छन । त्यसैले तपाईं सधैं चनाखो रहनु जरुरी छ ।"
९) ईन्टरनेटमा जे पायो त्यही फाइलहरु download नगरनुस् । " तपाइलाई यो थाहा हुनु जरुरी छ कि ईन्टरनेटमा राम्रो मात्र हैन तपाईंको कम्प्युटरलाई बिगार्ने धेरै नराम्रो फाइलहरु पनि पाईन्छन । त्यसैले ईन्टरनेट बाट फाइलहरु download गर्दा धेरै ध्यान दिनु पर्छ । तपाईंलाई शँका लागेका वा अनावश्यक फाइलहरु सके सम्म download नगर्नु नै राम्रो ।"
१०) आफ्नो घरको परिवार वा जस्ले तपाईंको कम्प्युटर चलाऊछ उनिहरुलाई पनि थाहा हुनु पर्छ कि के गर्नु पर्छ virus बिरुद्द सुरक्षा गर्नको लागि " यो एकदम महत्वपूर्ण कुरा हो कि कम्प्युटर चलाऊने सबैले कम्प्युटरको सुरक्षाको बारेमा पनि जान्नु जरुरी छ । उनिहरुलाई थाहा हुनु पर्छ कि कसरी anti-virus Software लाई Update गर्ने कसरी Password ले सुरक्षा गर्ने आदी आदी ।"

Types of Networks

2009-12-19T23:30:00.000-08:00

Peer to Peer - A peer to peer network is one in which lacks a dedicated server and every computer acts as both a client and a server. This is a good networking solution when there are 10 or less users that are in close proximity to each other. A peer to peer network can be a security nightmare, because the people setting permissions for shared resources will be users rather than administrators and the right people may not have access to the right resources. More importantly the wrong people may have access to the wrong resources, thus, this is only recommended in situations where security is not an issue.

Client/Server - This type of network is designed to support a large number of users and uses dedicated server/s to accomplish this. Clients log in to the server/s in order to run applications or obtain files. Security and permissions can be managed by 1 or more administrators which cuts down on network users med-ling with things that they shouldn't be. This type of network also allows for convenient backup services, reduces network traffic and provides a host of other services that comes with the network operating system (NOS).

Centralized - This is also a client/server based model that is most often seen in UNIX environments, but the clients are "dumb terminals". This means that the client may not have a floppy drive, hard disk or CD ROM and all applications and processing occur on the server/s. As you can imagine, this requires fast and expensive server/s. Security is very high on this type of network.

OSI Seven(7) Layer Model

2009-12-19T23:26:00.000-08:00

The OSI networking model is divided into 7 layers. Each layer has a different responsibility, and all the layers work together to provide network data communication.

* Physical - The Physical layer is the specification for the hardware connection, the electronics, logic circuitry, and wiring that transmit the actual signal. It is only concerned with moving bits of data on and off the network medium. Most network problems occur at the Physical layer.

* Data Link - The Data Link layer is the interface between the upper "software" layers and the lower "hardware" Physical layer. One of its main tasks is to create and interpret different frame types based on the network type in use. The Data Link layer is divided into two sub-layers: the Media Access Control (MAC) sub-layer and the Logical Link Control (LLC) sub-layer.
o LLC sub-layer starts maintains connections between devices (e.g. server - workstation).
o MAC sub-layer enables multiple devices to share the same medium. MAC sub-layer maintains physical device (MAC) addresses for communicating locally (the MAC address of the nearest router is used to send information onto a WAN).
* Network - The Network layer addresses messages and translates logical addresses and names into physical addresses. It also manages data traffic and congestion involved in packet switching and routing. It enables the option of specifying a service address (sockets, ports) to point the data to the correct program on the destination computer.

* Transport - The Transport layer provides flow control, error handling, and is involved in correction of transmission/reception problems. It also breaks up large data files into smaller packets, combines small packets into larger ones for transmission, and reassembles incoming packets into the original sequence.

* Session - The Session layer handles security and name recognition to enable two applications on different computers to communicate over the network. Manages dialogs between computers by using simplex(rare), half-duplex or full-duplex. The phases involved in a session dialog are as follows: establishment, data-transfer and termination.

* Presentation- The Presentation layer determines data exchange formats and translates specific files from the Application layer format into a commonly recognized data format. It provides protocol conversion, data translation, encryption, character-set conversion, and graphics-command expansion.

* Application - The Application layer represents user applications, such as software for file transfers, database access, and e-mail. It handles general network access, flow control, and error recovery. Provides a consistent neutral interface for software to access the network and advertises the computers resources to the network.

Here is an idiotic, yet easy way to remember the 7 layers. Memorize the following sentence: All People Seem To Need Data Processing. The first letter of each word corresponds to the first letter of the layers starting with Application and ending with the physical layer.

Layer 1 – The Physical Layer

* Translates data into bits, or bits into data
* Deals only with electrical and mechanical level of data communication, which builds the foundation to allow higher OSI layers to walk through it.
* Physical Layer devices are:
o NIC Cards
o Ethernet Hubs
o Repeaters
o Multistation Access Units (MAUs)
o Transceiver
o Media Filters

Layer 2 – The Data Link Layer

* Provides flow and error control and synchronization for the Physical Layer
* Is made up of the Logical Link control and MAC sublayers
* Data Link Layer Devices are:
o Bridges
o Switches
o Brouters

The Protocols that operate at the Data Link Layer are:

* Point-to-Point Protocol (PPP)
* Serial Line Internet Protocol (SLIP)
* High-Level Data Link Control (HDLC)
* Logical Link Control (LLC)
* Link Access Protocol (LAP)

Layer 3- The Network Layer

* Manages communications routing for packets that are destined for addresses that are not on the LAN
* Uses routable protocols to deliver packets across interconnected networks joined by routers.
* Device which operate at the Network Layer are:
o Routers
o Connectionless Oriented services

The two main protocols that operate at the Network Layer are:

* TCP/IP
* IPX/SPX

Layer 4 – The Transport Layer

o Manages the end-to-end control and error checking by providing an end-to-end connection between the source and the destination node to ensure reliable data delivery
o Also responsible for providing end-to-end recovery, flow control, and releasing the connection

Connectionless-Oriented Protocols that operate at this layer are:

* UDP

Connection-Oriented Protocols that operate at this layer are:

* TCP/IP
* SPX/IPX

Layer 5 – The Session Layer

* The session layer manages the establishment of a continuing series of requests and responses between the applications at each end.
* Mainframes used to use this layer – modern networking does not.

Layer 6 - The Presentation Layer

* Usually part of the Operating System
* It prepares incoming data for the Application layer and formats outgoing data that the Application layer sends and receives.
* Data compression and data encryption.

Layer 7 – The Application Layer

* The top layer of the OSI model
* Provides information services
* FTP and Telnet access the OSI model at this layer.

Microsoft Disk Operating System

2009-11-22T23:42:00.000-08:00

An operating system is a set of specialized programs, which coordinate the activities, resources, and operations of it are various hardware peripherals. It is heart of the computer system software.

DOS: Among other operating system MS-DOS is the most common single task (only one task at a time) operating system in use today in personal computers. It is a production of Microsoft Inc. USA. Similarly DOS developed by IBM (International Business Machine) is known as PC DOS.

BOOTING: It is a process by which a computer loads an operating system software (e.g. MS-DOS) from secondary storage media (e.g. Floppy Diskette or Hard Disk) into the main memory of computer and gets ready to accept data, commands and instructions.

Or

It is a process for making the computer ready for working.

Booting is of two types:

Cold Booting: Starting the computer by switching on the main switch (Power) of system unit or starting a cold computer is called Cold Booting.

Warm Booting: Re-booting the computer, which is already been started.

This can be done in two ways:

Press "Reset" button available on your system unit.

Press Ctrl + Alt + Del keys in Keyboard at a time.

When the machine is switched on, a number of steps are undertaken before the system is ready. The steps are:

The system does the POST [Power On Self Test], where the system automatically checks the memory, the devices like the KEYBOARD, VDU, MOUSE (if attached), the disk drives are so on and if any discrepancy is detected, relevant messages are displayed on the screen.

Searches for the booting files i.e. IO.SYS, MSDOS.SYS & COMMAND.COM from the drive, which was set up in BIOS.

On finding the booting files, it first loads the IO.SYS file, which shall look after all, inputs to the system and outputs form the system. Then it loads MSDOS.SYS that looks after the disk operations, and lastly COMMANA.COM is loaded which is to ensure the execution of the commands.

Before loading COMMAND.COM the system searches a very import yet optional file called CONFIG.SYS, the function of this file is to configure the system according to the user's specification.

After COMMAND.COM is loaded the system again searches for another important file AUTOEXEC.BAT and if found, system executes it.

Now when all files are loaded, the system provides the user with a PROMPT on the screen. The prompt looks like A:> or C:>. Only when the prompt appears on the screen we know that the system is ready functioning.

Files: Every DATA and PROGRAM in the computer system is stored in the form of Files. The files in DOS have two parts namely Base name and extension. A base name has maximum of eight characters whereas extension can have a maximum of 3 characters. Filename and Extension must be separated by a period (.) not by space. It must be a single. No empty space allowed in between.

Program Files: They are the files having some special instructions stored in them, which executes and provides the instructed output when they run. Files with the extension like EXE, BAT, SYS and COM are the examples of program files.

Data Files: They are the files which are just used to store data and records in them. They do not execute and are shared by the program files when a program needs to get the required data. These files may or may not have extensions. All the files without the extension like that of the program files are the data files.

Command: A command is a request or instruction to the computer, which when feeded in the computer through input device is process and implemented by computer accordingly. They are of two types:

Internal or In-Built-Up Command:

All internal commands are associated with COMMAND.COM file and it is loaded while booting and remains in Computer's Main Memory (RAM) until we you turn off the CPU. So, whenever you issue an internal command it runs immediately.

Following are the MS-DOS internal commands:

CLS Clear the screen.

Example: CLS

DATE It allows users to view and reset the system date.

Example: DATE

TIME It allows users to view and reset the system time.

Example: TIME

COPY CON It allows users to create and save a file under the given name. It is the worst word-processing command, which does not allow us to modify and print the contents. [Note: Do not use the following extension BIN, SYS, COM, EXE].

Example: COPY CON Ramesh.txt

Dear Girish

How is your computer class is going?

See you soon

F6, [saves & exits to command prompt].

or

CTRL + C [exits to command prompt without saving]

TYPE It allows users to view content of the given file.

Example: TYPE Ramesh.txt

REN or RENAME It allows users to change the name of a file.

Example: REN Ramesh.txt Ramesh1.txt

Or

RENAME Ramesh.txt Ramesh1.txt

DIR It allows us to view the contents (e.g. files and directories/folders) of current path.

Examples:

a) DIR Displays the content of current directory, continuously.

b) DIR/P Displays the content of current directory, pausing between the pages.

c) DIR/W Displays only the name of the directory in width format.

d) DIR/L Displays in lowercase.

e) DIR *.EXE Displays only those files having EXE extension.

[Note: Here '*' is called a "Wild Card". It is used to represent nothing, one or more unknown characters while specifying the filename and extension.]

f) DIR P*.EXE Displays only those file starting with letter 'P' and having extension "EXE".

g) DIR R???.* Display file name starting with 'R' having 4 characters. Extension any.

[Note: the "?" (a question/what/interrogative sign) is also a wild character represents either nothing or one unknown character when we use it in filename or extension.]

h) DIR > PRN Send the directory list to the printer.

DIR > file1 Save the list of directory in to file named file1.

DEL It allows us to erase one or more unwanted files.

Example: DEL file1

VER Displays the version/ edition/generation of MS-DOS being currently used.

Example: VER

VOL It helps us to know the volume label (i.e. name) of a floppy diskette or hard disk.

Example: VOL

Directory / Folder Maintenance:

What is Directory?

A directory is just like a folder of a cabinet (or room of a house) utilized to store the similar type of files. As it is used to store the systematically, it helps us to search for a particular file in a very short period.

Example C:\Users\Rama\Data

Where C: = Drive name or Root Directory of drive C.

Users = Directory or Folder.

Rama = Sub-directory or sub-folder.

Data = Sub-directory of Sub-folder.

\(Back slash) = sign is used to separate the drive name, folder, subfolder and filename.

So any directory created in Root Directory of any drive is called a "Directory or Folder".

Any directory created inside a directory is called "Sub-Directory or Sub-Folder".

Root directory, Directory and Sub Directory are the relative term.

MD Creating a directory, or Make Directory.

Example: MD LETTER Creates directory called LETTER.

CD Changing Directory.

CD.. Coming out from current directory.

CD\ Coming to root directory.

CD letter Going inside the directory called letter.

RD Remove Directory.

[Note: the Directory to be removed must be empty, the command should be issued outside from the directory to be removed.]

PROMPT: Changes the appearance of MS-DOS prompt.

Example: PROMPT $P$D$G {P=path, D=Date, G= Greater than sign}

PATH: Establishes or shows or remove the searching path (drive & directory) for executable program file.

Example: PATH C:\WINDOWS Establish the searching path as WINDOWS.

PATH Display current path.

PATH; Clears the current path.

COPY: It is used to make the duplicate of one or more files.

Example: COPY C:\file1 A:\file2 Copy file1 form C: to A: and change name as file2.

COPY file1 + file2 + file3 Newfile Merging three file together and put it into Newfile.

C: A: Changing the Drive.

Example: C: A: change working drive from C: to A:.

External Command.

All the MS-DOS commands except those mentioned above are the external commands. It runs slower than internal command. It is stored in secondary storage devices. They are specially designed for some specific purpose.

1.CHKDSK: Check the status of a disk and displays a status reports. It can fix the problems but is not much reliable.

Example: CHKDSK C: Run check disk on C: drive.

2.SCANDISK: Checks disks for damages, and repairs them, if needed. It is more reliable and recommended command to fix the disk and file errors.

Example: SCANDISK C: Run scandisk on C: drive.

3.ATTRIB: Displays or changes file attributes.

Any file has certain specific characteristics or qualities that define the nature of the file; this in turn determines the access of the file. The Attributes available under DOS are R, A, H and S.

R [Read-Only file attribute] The file with this attribute can be displayed or read only but cannot be modified in any way or neither can they be deleted.

A [Archive file attributes] With this attributes, we can mark the files. The MSBACKUP, XCOPY and RESTORE commands can copy only those files marked with this attributes.

S [System file attributes] it designates a file as a system file. Files with I this attributes cannot be seen, edited and run.

H [Hidden file attributes] the files with these attributes are not normally displayed in directory listings, such file cannot be edited, deleted by can be run, if we know their names.

+ Set an attributes.

Remove an attribute.

Example: ATTRIB Displays attributes of all files in current directory.

ATTRIB +R Nepal Assign read only attributes to file called Nepal.

4.DELTREE: Deletes a directory and all the subdirectories and files in it.

Example: DELTREE C:\temp Delete directory called temp.

[Be sure to use this command before you use it. It can be mishandle to create problems]

5.DISK COPY: Copies the contents of one floppy disk to another. It is duplicating the floppy diskette. [Note: A hard disk can not be disk copied.]

Example: DISK COPY A: B: Make B:duplicate copy of A:

6.DOSKEY: Loads the DOSKEY program into memory. It will allow us to recall old command recently used.

Example: DOSKEY Starts storing old command now unwands.

7.EDIT: It is a powerful MS-DOS text editor, which allows us to create, edit, save, open, duplicate and print a TEXT file.

Example EDIT Gita.txt Create text file called Gita.txt and allows us to edit.

8.FORMAT: A new disk, including a hard disk, must to prepare before it is used for the first time. This step is called formatting.

Example: FORMAT A: It formats a floppy drive.

9.LABEL: Creates, changes, or deletes the volume label of a disk. User can give a name to each disk, which will be stored internally as information. This name is known as volume label.

Example: LABEL Displays the volume label and serial number of the disk in current drive, if they exist. Then it prompts you to enter the new volume label (not longer than 11 characters) or delete the existing volume label.

10.MORE: Displays one screen of output at a time. This command is commonly used too view long text files.

Examples: DIR | MOREDisplays the directory listing one screen at a time. Press a key to see the next screen. This command does the same function of DIR/P .

11.MOVE: Moves files to the drive and directory you specify. It also renames files and directories.

Example: MOVE A:\HARI.TXT C:\DATA\SITA.TXT Moves the file named HARI.TXT from drive A into the DATA directory on drive C and in the same time renames the file to SITA. TXT.

12.SYS: Copies MS-DOS system files (IO.SYS & MSDOS.SYS) and command interpreter (COMMAND.COM) to a disk you specify.

Example: SYS A: Copies the system files and files and command interpreter from current drive into the disk on drive A.

13.UNFORMAT: Restores a disk erased by the FORMAT command or restructured by the RECOVER command.

Example: UNOFROMAT A: Restores the formatted disk in drive A without listing all the files and sub _ directories.

14.XCOPY: Copies directories, subdirectories and their files (expect hidden and system). The XCOPY command first loads the specified directories and files into RAM as much as it can hold and after then, copies them from RAM to target drive &folder. So xcopy is faster than COPY command (The COPY command copies one file at one time from source to target location however RAM has the sufficient spaces to hold more files)

Examples: XCOPY A: B:/S/E Copies all the files and sub -directories (including the empty sub-directories) from the disk in drive A to the disk in Drive B.

15.TREE: This command is needed usually since a disk can have numerous directories and sub directories and all of them filled with files, so at times it becomes really difficult to locate particular file or group of files. This command graphically displays the directory structure.

Example: TREE C: Displays the names of all sub-directories on the disk C:.

16.PRINT: Prints the contents of MS-DOS Text File. This command can print in the background if you have an output device connected to your system serial or parallel ports.

Examples: PRINT COW Sends the contents of Cow to the computer.

17.DISKCOMP: Compares the contents of two floozy diskettes. This command performs the track-by-track comparisons. It determines the number of sides and sectors per track to compare based on the format of the first disk you specify.

Example: DISKCOMP B: A: Compares the disk in drive B with the disk in drive A.

18.SORT: Sorts input and writes results to the screen, a file, or another device.

Examples: SORT/R Sorts the paragraphs/records of MAILLIST.TXT in reverse order and then displays the output on screen

19.MSD: The MSD (Microsoft Diagnostic Tool) command provides detailed technical information about your computer.

Example: MSD Runs the Microsoft Diagnostics tool, analyzes the computer and then, displays different headings. You can choose the desired heading to view the corresponding technical information. Press F3 to quit from Microsoft Diagnostic tool.

20.MEM: Displays the amount of used and free memory in your system. It displays the information about allocated memory areas, free memory areas and the programs currently loaded into memory.

Example: MEM

Checks and then displays the amount of used and free memory in your system.

Memory Type Total Used Free

Conventional 640k 144k 496k

Upper 91k 91k 0k

Reserved 384k 384k 0k

Extended (XMS) 15.269k 273k 14.996k

Total Memory 16.384k 892k 15.492k

Total under 1 MB 731k 234k 496k

HELP: Starts MS-DOS help on MS-DOS commands.

Example: HELP Displays the MS-DOS help table of contents. From the table of contents, you can choose the desired command topic you want to view. HELP CHKDSK Displays the help about CHKDSK command.

FAST HELP: When used alone, displays the list of all MS-DOS commands and gives a brief explanation of each. The information about the FAST HELP command displays in similar to, but less detailed than, the information found in MS-DOS help. OR The FAST HELP along with the any MS-DOS command, provides help information about that.
Example: COMMAND /? Displays help information on that command.

How to Save Battery Life of Your Digital Camera

2009-11-05T03:18:00.000-08:00

1. Most of the cameras these days come with “Auto Power Saving” mode. Make sure you keep it on when you are not using the camera for a while.
2. Always make it a point to buy genuine and large capacity batteries. Keep away from the Grey Market stuff. Not just your batteries, even your camera’s life will be at stake.
3. I have seen many starters/amateurs using Flash unnecessarily. Avoid using Flash until absolutely required. Or better keep Flash in AUTO mode!
4. Think before you CLICK! Give a thought on what the resolution of the pictures you are taking right now should be. Lesser the resolution, lower the battery consumption!
5. Avoid using the LCD screen when focussing. Personally, I prefer using the view finder since it gives me the real view of the subject I am clicking. If you can get use to view finder, it will surely bring down the battery consumption a great deal.
6. Disable unnecessary settings in your camera like ‘Auto Chase Focus’ or ‘Motion detector’.
7. Some Digi-cams are known to consume battery even when they are switched off. So don’t forget to remove the batteries when it is not in use.
8. Use the Zoom option of your camera sparingly. The motor which zooms in/out the lenses uses the battery.
9. Its a well known thing that the battery life is shorter in cold climates. Make sure you keep the camera warm as much as possible.
10. Avoid erasing the images from the camera directly.
11. Use AC adapter when you are transferring the photos to your PC. Common sense! Downloading photos to your hard drive is a steady battery drain.
12. Avoid pressing the shutter button half way down when you don’t plan to take a photo. The camera goes through a series of processes getting ready to shoot a digital photo, that means huge power drain.
13. Constantly previewing the pictures on the digital camera, is something that we are all guilty of. Avoiding this is surely tough! But its definitely worth it!
14. Don’t keep turning the cam on & off. It empties your batteries really quickly

Microsoft Windows Se7en Wallpapers

2009-10-31T09:23:00.000-07:00

Windows Se7en Creative

Grasmere Village

Rocky Headland

Old English Cottage

Dew on Pink Dalhia Petals

Beach Waves

Altai Mountain

Se7en Girls

Vision Se7en

Time to learn about Microsoft Excel 2007

2009-10-08T02:49:00.000-07:00

Microsoft Excel is an electronic spreadsheet that runs on a personal computer. You can use it to organize your data into rows and columns. You can also use it to perform mathematical calculations quickly.

Lesson 1: Entering Text and Numbers

This teaches Microsoft Excel basics. Although knowledge of how to navigate in a Windows environment is helpful, this tutorial was created for the computer novice. This lesson will introduce you to the Excel window. You use the window to interact with Excel.

Lesson 2: Entering Excel Formulas and Formatting Data

A major strength of Excel is that you can perform mathematical calculations and format your data. In this lesson, you learn how to perform basic mathematical calculations and how to format text and numerical data.

Lesson 3: Creating Excel Functions, Filling Cells, and Printing

By using functions, you can quickly and easily make many useful calculations, such as finding an average, the highest number, the lowest number, and a count of the number of items in a list. Microsoft Excel has many functions you can use. You can also use Microsoft Excel to fill cells automatically with a series. For example, you can have Excel automatically fill your worksheet with days of the week, months of the year, years, or other types of series. This lesson teaches you how to use functions, how to create a series, how to create headers and footers, and how to print.

Lesson 4: Creating Charts

In Microsoft Excel, you can represent numbers in a chart. On the Insert tab, you can choose from a variety of chart types, including column, line, pie, bar, area, and scatter. The basic procedure for creating a chart is the same no matter what type of chart you choose. As you change your data, your chart will automatically update. This lesson teaches you how to create a chart in Excel.

Microsoft Excel 2007 Keyboard shortcut keys

This topic informs you about shortcut keys in Microsoft Excel 2007.

Network Hardware

2009-09-18T21:06:00.000-07:00

If you want to read about network hardware's then click here READ

Microsoft Powerpoint 2007

2009-09-12T22:43:00.000-07:00

PowerPoint is a presentation software package. With PowerPoint, you can easily create slide shows. Trainers and other presenters use slide shows to illustrate their presentations.

Just click here to Learn how to work with power point

Learn More About Viruses

2009-08-09T10:56:00.000-07:00

Boot Sector Virus
• Attaches itself to the boot sector of a floppy disk or an executable file
• Copies all or part of itself onto the boot sector of your hard drive when you turn on your computer or try to run an executable file
• Can get one from an infected disk or the Internet

File-Infecting Virus
• Attach themselves to executable files associated with other programs
• Mostly attach to .EXE or .COM files but can infect .SYS, .DLL, and .BIN files
• When you open a program that contains a virus, the virus loads into your computer’s memory and then infects any other executed program.

Macro Virus
• Affect the Microsoft Word and Excel templates
• Once infected, every document or spreadsheet opened with the program becomes corrupted.
• Widespread

Polymorphic Virus
• Can infect the boot sector, files, or both
• Can modify their appearance and signature
• Use code alteration and encryption so that they can not be detected by anti-virus search screens

Stealth Viruses
• Infects a file by adding bytes to the infected file, and then subtracting the same number of bytes to from the directory entry of that file, so that it appears that nothing is different
• Stay in memory

Multipartite Virus
• Can infect the boot sector and executable files
• Combine characteristics of memory-resident and nonresident files, and boot sector viruses incorporating stealth and polymorphic characteristics.

Meta Virus
• The first viruses known to infect data files and work on multiple platforms
• Normally carried in data files for Microsoft Word and AmiPro documents
Other Destructive Programs

Worms
• Often mistaken for a virus
• A single destructive program on a single system
• Often planted by someone with direct access to the system
• Do not replicate themselves

Trojan Horses
• Appears to be a program
• Waits for an user to execute it
• Can infect other files on the system, or other computers on the network

Logic Bombs
• Similar to a Trojan Horse but it has a timing device that is keyed to go off on a certain day or time
• Can do damage anywhere from destroying data on the hard drive to releasing a virus

Computer Viruses

Dear, Sir/Madam

Do you familiar with "Computer Viruses" if not please read below:

A virus is a software program designed to infect, destroy or interfere with a computer or software program. A Virus is a software program capable of reproducing itself and usually capable of causing great harm to files or other programs on the same computer. This computer program can copy itself and infect a computer without the permission or knowledge of the owner. It can be transmitted between computers via networks (especially the Internet) or removable storage such as CDs, USB drives, floppy disks, etc., generally without the knowledge or consent of the recipient. It's a very dangerous computer program with the characteristic feature of being able to generate copies of it (self), and thereby spreading. Additionally most computer viruses have a destructive payload that is activated under certain conditions. A computer virus is a piece of code that is secretly introduced into a system in order to corrupt it or destroy data. Often viruses are hidden in other programs or documents and when opened, the virus is let loose. This is a self-replicating computer program that spreads by inserting copies of itself into other executable code or documents.

A virus can infect other programs by modifying them to include a possibly evolved copy of itself. Programming code created as a prank or as a malicious action that secretly affects other programs and causes unwanted consequences. It can damage system's settings and memory, so it is possible for virus to generate run time error messages as well.

If your computer is already running a virus protection program make sure it has latest updated patch or ".dat" file.

According to my experience a truth is that a true virus cannot spread to another computer without human assistance. So you have to be careful yourself while working at computer/Laptops.

If you are suffering from computer viruses please feel easy to contact me.

What is PSU(Power supply Unit)

2009-07-27T02:52:00.000-07:00

PC Power supplies use switcher technology to convert the AC input to lower DC voltages. The 3.3- and 5-volts are typically used by digital circuits, while the 12-volt is used to run motors in disk drives and fans.

If there is any one component that is absolutely vital to the operation of a compute r, it is the power supply. Without it, a computer is just an inert box full of plastic and metal. The power supply converts the alternating current (AC) line from your home to the direct current (DC) needed by the personal computer. In this article, we'll learn how PC power supplies work and what the wattage ratings mean.

In a personal computer (PC), the power supply is the metal box usually found in a corner of the case. The power supply is visible from the back of many systems because it contains the power-cord receptacle and the cooling fan.

The term power supply is more commonly abbreviated to PSU, this will be used from hereon in.

Telecommunications equipment is designed to operate on voltages lower than the domestic Mains voltage. In order to reduce this voltage a PSU is used.

To provide a useable low voltage the PSU needs to do a number of things:-

Reduction of AC Mains

This is achieved by using a device known as a Transformer an electromagnetic device consisting of an ferrous iron core which has a large number of turns of wire wound around it, known as the Primary Winding

The ends of these turns of wire being connected to the input voltage (in this case Mains AC).

A second number of turns of wire are wound around the Primary Winding, this set being known as the Secondary Winding.

The difference between the number of turns provides us with a way of reducing (in our case) a high AC voltage to a lower one.

Conversion of AC to DC

To convert our now low AC voltage to DC we use a Rectifier Diode connected to the Secondary Winding.

This is a silicon diode, which has operation analogous to a bicycle tyre valve (as the valve only allows air to flow into the tyre, the diode only allows current to flow in one direction)

As our low AC voltage will be working at a frequency of 50Hz (Mains AC frequency) it is desirable to reduce the inherent hum on this to a lower level.

This is achieved by a technique known as Smoothing (“Ironing” out the bumps in the AC).

A simple way to reduce the hum is to use Full Wave Rectification.

Today this is usually done by four diodes in a bridge configuration known as a Bridge Rectifier. (This can be four individual diodes or a dedicated self contained package)

Regulation of Output Voltage

The Electrolytic Capacitor is a device capable of storing energy the amount of energy and the time it remains stored depending on the value.

In a simple PSU the easiest way to provide regulation to compensate for varying load conditions is to use a pair of relatively high value Electrolytic Capacitors.

Their values in this case being in the region of 470uF to 2000uF depending on the application and the amount of current required from the output of the unit.

One of these capacitors is connected across the DC output of the rectifier diode(s) or bridge, this capacitor also providing an extra degree of smoothing the output waveform.

The second capacitor is connected via a low value, medium to high wattage resistor, which assists in limiting the current demand.

Protection against excessive voltages

In a simple PSU the easiest way to do this is by providing fuses at the input to the transformer, generally in the live side of the mains supply, also at the DC outputs.

In the event of an excessive input voltage, or excessive current being drawn from the output, one of these fuses should normally blow protecting the PSU and the equipment connected to it.

The transformer may also be fitted with an internal or external thermal fuse, which will open if the transformer becomes hot due to the aforementioned conditions.

Other PSU’s

There are lots of other types of PSU, some of which are much more complex in their design and operation and are beyond the scope of this overview.

Power supplies, often referred to as "switching power supplies", use switcher technology to convert the AC input to lower DC voltages. The typical voltages supplied are:

3.3 volts

5 volts

12 volts

The 3.3- and 5-volts are typically used by digital circuits, while the 12-volt is used to run motors in disk drives and fans. The main specification of a power supply is in watts. A watt is the product of the voltage in volts and the current in amperes or amps. If you have been around PCs for many years, you probably remember that the original PCs had large red toggle switches that had a good bit of heft to them. When you turned the PC on or off, you knew you were doing it. These switches actually controlled the flow of 120 volt power to the power supply.

Today you turn on the power with a little push button, and you turn off the machine with a menu option. These capabilities were added to standard power supplies several years ago. The operating system can send a signal to the power supply to tell it to turn off. The push button sends a 5-volt signal to the power supply to tell it when to turn on. The power supply also has a circuit that supplies 5 volts, called VSB for "standby voltage" even when it is officially "off", so that the button will work.