Computer Hardware & Networking & Technology News

Types of Computer Viruses

2009-09-16T07:21:00.000-07:00

Computer Virus is a program written that can attaches to file. When the infected file is opened, the virus infects other files on the system, and also spreads to other systems with the help of infected files. Viruses damage the system by deleting files on the system, increasing the file sizes, or automatically formatting the system.

1. Boot Viruses

The boot sector viruses copies the virus code in the boot sector of the disk, this ensures that the virus is always executed and loaded in the memory when the sytem starts. Once in the memory , the virus infects other files and floppy diks inserted in the drive, and spread it to other systems. For example, the virus Tequila onfects all the EXE files on the system and also infects the Master Boot record of the hard disk.

2. Polymorphic Viruses

A person can keeps on changing the way he looks to disguise himself this makes it difficult to trace a person. Similarly, polymorphic viruses are coded in such a way that they infect a system and change their signature before infecting the next system. Thus, the Antivirus software finds it difficult to identify this virus , as it looks different after every infection.

3. Macro Viruses

Macros are blocks of code written to automate frequently performed tasks and embedded in a program file such as Word document or an Excel worksheet. When a Macro having the virus code is executed, it infects the files on the system.

4. Worms

Worms are programs that replicate and spread to other systems. A Worm resides in the system memory and spreads without attaching itself to a file. They may cause damage to the system such as deleting files from the system and may also the system may slow down. For example , the worm Mwlissa attaches itself to an email and sends the email to all the contacts specified in the users address book, it also clogs email servers.

5. Trojans

Trojan is a program file that claims to do something but it actually does something that is not required. For Example, a Trojan may pose a computer game but when it is executed it may delete files from your sytem or email the passwords stored in your system to the Trojanwriters email address.

6. Spywares

Spyware stores personal information and surfing habits of the user sends them to its web site without informing the user. Many spywares get installed as a free download while installing an application. It does not harm the computer as a virus does but is used to get user information for monetary gains.

How modem works

2009-08-26T21:13:00.000-07:00

Modem is a communication device that enables a computer to transfer data over the telephone or cable lines. The word Modem is a short form for Modulator/Demodulator.

Working of a Modem:

A modem is a device that is used for modulation and demodulation of information. The working of a modem includes the following steps :

1. Software such as Auto Dialers in the computer activates the modem, which listens for the dial tone on the phone line.

2. Once the dial tone is available, the modem dials a specified number.

3. The modem at the receiving end answers the call and sends out a signal to the modem at the sending end. This results in establishing a connection.

4. The modem at the sending end converts digital signals from a computer to analog signals that can pass over the telephone line.

5. The modem at the receiving end converts analog signals back to digital signals that can be used by the computer.

6. The step 4 and 5 keep repeating during the online session.

7. Once the online session is over, the computer issues a command to disconnect the session.

Shows the working of a modem

At the sending end ------ Telephone lines------------------------At the receving end

Modem Modem

Sending computer Receving computer

Types of Computers

2009-08-18T21:57:00.000-07:00

Computers perform a vast range of functions . Some computers are so powerful that hundred or even thousands of users can use them at a single instant. There are four main types of computers namely Microcomputer , Minicomputers, Mainframes and Supercomputers.
Microcomputer :-
Microcomputer, also known as a personal computer,is a digital computer that works on a micrprocessor. Microcomputers are small machines designed for individual users. Average people who have a basic knowledge of computers can use microcomputers. Individuals in homes and offices are major users of the micrcomputer. It is an expensive computer that performs various tasks such as the word processing , desktop publishing and accounting. It is also useful for running spreadsheets and adatabase management applications.The microcomputer has several disadvantages , such as small size , low cost and portability. Its main disadvantage is that the speed of processing is low as compared to other types of computers.
Minicomputer :-
Minicomputer is midsized and multi-user computer . Microprocessing is the process of running multiple programs or processes at a given instant . The minicomputer is a smedium range computer. It is also known as the mis-range servers. Minicomputers fakll in between the microcomputers and the mainframes.The qadvantage of using minicomputer is that it can cater to multiple users at a lower cost than mainframes . Minicomputers are ideal for small-sized companies. The disadvantage of the minicomputers is that they are large and bulky.
MainframeInitially, mainframes were huge computers occupying entire rooms or floors. Mainframes were used to serve as the center of large systems in companies. They were designed to serve the purpose of centralized computing instead of the distrubuted computing. With the development in the field of computing , the size of mainframes has reduced and the power has increased.The advatage of mainframe is that it can support many users and instructions due to its incomparable memory and processing speed. The disadvatage of mainframe is its huge size and enermous cost.
Supercomputers:-
Supercomputer is the fastest and most expensive type of computer. Supercomputersspecialize in high speeding Processing of data. Applications that use large amounts of calculationsuse supercomputers. Some of these applications are molecular chemistry. Nuclear research.The advatage of supercomputers is their speed , which is unattached by any other type of computer.. The major disadvatage of supercomputers is the heat they generate during their operation.The disadvantage

DNS Zones

2009-08-16T23:58:00.000-07:00

A DNS Zone can be defined as a contiguous part of a name space for which a server has been assigned authority. A server can have authority for a multiple zones and a single Zone can have multiple domains. For example, a single server can have the authority for the sample.com zone as well as the example.com zone and each of these zones can have multiple domains.

The related domains such as .com , sample.com and mycompany.com.sample.com can ve converted into zones by using delegation.

Two different types of zones can be created viz; Forward look up zone and reverse look up zone. In forward look up zone zones, the Dns server map FQDN with the IP addresses and it is vice -versa in reverse look up zones.Therefore , queries for resolving FQDNs to IP addresses are answered by forward look up zones and reverse look up zones answer queries to resolve IP addresses to FQDNs.The New zone can wizard is used for creating a new forward or reverse look up zone. In both the cases, you create a new zone by right clickingt the server for which you want to create a new zone and then selecting the new zone option. This will launch the New zone wizard. However, you can create New zones using the configuration a DNS server wizard.

There are three Zone types :

1) Primary zones : Provides the source of all zones with in a domain. Using the data from this zone , a secondary zone can be created and used as a backup.

2) Secondary zones : Contains a backup for the primary zone.

3) Stub Zones : Contains only those resource record those are necessary to identify the servers authoratiove for the master zone.

Windows Internet Name service ( WINS) in windows 2003

2009-08-07T20:59:00.000-07:00

NetBIOS names are required for establishing networking services in earlier version of Microsoft windows operating system. NetBIOS over TCP/IP provides three methods to resolve computer names to IP addresses: broadcast , the LMHOSTS file and WINS. The default technique used is name resolution by broadcast. For Network configuration that include routers and WAN links, an LMLHOSTS file is used to supplement the broadcast method.

Although NetBIOS and NetBIOS names can be used with network protocols other than TCp/Ip. WINS was designed specifically for providing support to NetBt. WINS is required when users access resources that have NetBIOS names . IF you do not use WINS in such networks, you will not be able to connect to a remote network resource by using its NetBIOS name unless you use Lmhosts files and you might be unable to establish file and print sharing conncections.

WINS maps the Netbios names to IP addresses. It was developed to solve the problem that occured when NetBIOS name resolution was used. The WINS database is updated automatically when any dynamic address configuration changes occur. This is because WINS registrations are done automatically each time the client starts and joins the network. The user or the network administrator does not have to change any settings manually.

WINS has the following advatages over the NetBIOS name resoltion techniques:

1) Reduces the NetBIOS name query broadcast traffic because client query a WINS server directly instead of broadcasting their queries.

2) Supports NetBIOS name registration and resolution in an enviornment where DHCP enable clients are configured for Dynamic TCP/IP address resolution.

3) Supports a central Management and duplicates name- to- address mappings to other servers running WINS.

4) Works with DNs in the same enviornment allowing combined name searches in both the namespaces.

Consider two computers, computer 1 and computer 2, both having windows server 2003 installed on them. YOu can use the Network monitor tool to capture the traffic between these two computers.

To create a network capture of a name resoltion:

1. Log on to computer 1 as administrator.

2. Select Start-> Run.

3. Enter Cmd in the open text box.

4. Click Ok. The command prompt window appears.

5. Type ipconfig/flushdns and press Enter.

6. Type nbstart-R and press Enter.

7. Select start-. All programs-> Administrative tools-> Network Monitor.

8. CLick OK.

9. Enter LOcal computer and select Local Area Connection.

10. Click Ok.

11. Select capture -> start to start a new capture.

12. Switch back to the command prompt, type ping computer 2 and press Enter.

13. After you receive four replies from computer 2, switch back to Network Monitor.

15. Select Capture -> Stop and view to stop and view the capture.

16. Look at the protocols listed in the new network capture.

17. Selct File->s ave as .

18. Enter Name resolution 1 in the file name text box.

19. Click the save button.

20. Exit Network monitor and close the command prompt window.

21. Log off computer 1.

Explaining Name Resolution

2009-08-07T06:01:00.000-07:00

A network is a collection of computers. For example, the internet is a network, which consists of millions of interconnected computers. Each of these computers has a unique Internet Protocol (IP) address. An Ip address is the address of the computer on the network. It identifies each computer as a distinct machine connected to the network. It consists of a series of four numbers, seperated by periods such as 251.145.14.98. Computers communicate each other by using their IP addresses.
Your access site or locations on the network by entering their names in the browser. For example it is easier to remeber a website as www.google.com , than to memorize its Ip address., 64.233.189.104 computers do not understand these names. The names you are entered converted into IP addresses, so that the site can be accessed. Name resolution is the process of mapping computer names to their assosciated IP addresses.
There are Two ways to resolve names :
1) Network Basic Input/Output System (NetBIOS )
2) Domain Name system (DNS)
Windows 2003 supports both of them. However DNS is Preferred.

Domain Name system (DNS)

2009-08-06T20:41:00.000-07:00

DNS is a service that maps domail names to their IP addresses. Domain names are user-friendly names that identify computers instead of their IP addresses. they are available only to computers using the TCP/IP protocol. They consists of two parts :

-> Host name - Identifies the computer on network

-> Domain name - Identifies the internet site

For example, take the name server1. moneycontrol.com. Here, server 1 refers to the computer and moneycontrol.com is the Domain name. When the entire term is combined, it is called a Fully Qualified Domain Name (FQDN)

DNS consists of multiple domain name servers, which store details about various domain names into their IP addresses. When you enter the domain name or site address into the browser, the DNS requests a domain name server to translate the information into the Ip address of the site. In case a particular server does not contain the information, the DNS forwards the request to the other servers, until it obtains the information. DNS is required for the following networks :

-> For computers belonging to network, which uses Microsoft Windows 2000 or Windows server 2003 domains, DNS has to be configured . DNS and Active Directory works in coordination with each other. Active Directory uses DNS as its locator service. A locator service helps clients to find hosts and services having an unknown location with in a given domain.

-> DNS has to be configured if you want to communicate with computers on your network or access the internet using DNS host names.

NetBIOS

2009-08-03T21:25:00.000-07:00

NetBIOS is an application programming interface (API ) that allows older windows computers to communicate with each other. It does not need to be configured in order to provide name resolution.
Windows 2003 server uses NetBIOS as a backup to DNS and to implement features such as browsing the network neighbourhood or My Network places.
NetBIOS is required for the following Networks:
1) Windows 2003 server networks support NetBIOS over TCP/IP ( Net BT) to provide backward compatability with previous versions of windows and for compatability with NetBIOS application.
2) Microsoft windows NT domains use NetBIOS names and NetBIOS protocol.
3) Necessary for network clients using applications that require NetBIOS name resolution.
As an example is the computer browser service which allows network browsing through windows network icon in windows explorer.
4) Required in networks for which DNS has not yet fully configured . An example is a computer workgroup in which no DNS server has been installed . NetBIOS broadcasts are required to resolve computer names.

How to Install Active Directory

2009-07-31T21:14:00.000-07:00

Active Directory installation requires planning. You need to consider the design of the organization's domain structure and domain name, the location of the database, log, shared system volume files, and the method of DNS configuration.

To Install Active Directory
1. Select All Programs -> Administrative tools -> Configure your server Wizard. The configure your server wizard appears.
2. Click Next. The Primary step screen appears.
3. Click Next. The server role screen appears.
4. From the server role screen select Domain Controller ( Active Directory ) From the server role list box.
5. Click Next. The summary of selections screen appears.
6. Click Next. The Active Directory Installation wizard message box appears.
7. Click the Continue Button. The Active Directory installation wizard appears.
8. CLick Next. The Operating system compatability screen appears .
9. Click Next. The Domain Controller screen appears .
10. Select the Domain Controller for a new domain option.
11. Click Next. The create new domain screen appears.
12. Select the Domain in a new forest option.
13. Click next. The new domain name screen appears.
14. Enter a domain name just like Godaddy.com in the full DNS Name for a new domain text box.
15. Click next. The NetBIOS Domain name screen appears.
16. Click Next. The Database and Log folders screen appears.
17. Click Next. The shared system volume screen appears.
18. Click Next. The DNS Registration Diagnostic screen appears.
19 . From the DNS Registration Diagnostic select the I will correct the problem later by configuring Dns manually.
20. Click Next. The permissions screen appears.
21. Select the permissions compatible only with windows 2000 or windows 2003 operating system option.
22. Click Next. The Directory services restore mode administrator password screen appears.
23. Enter a password in the restore mode password text box.
24. Re- enter the password in the confirm password text box.
25. Click Next. The simmary screen appears.
26. Click Next. Windows server 2003 installs the Active Directory services on the computer and prompts to restart the computer.
27. Click the Restart Now button. After you restart the server, the configure your server wizard appears.
28. Click the Finish Button

Introduction To Computer

2009-07-06T21:31:00.000-07:00

Computer is an integral part of every day life. We use personal computer to perform various tasks . Data storage and processing are the important tasks performed by the pc. It takes data from user, processes it, and gives the output in a prescribed manner . The use of PC makes mathematical calcilations easier . scientists use the pc for scientific applications such as weather forecasts , research and chemical analysis.Pc provides faster means of communication through the internet by sending and receiving e-mails. We can use the internet to gain information on any topic. We can use the pc for entertainment, such as for watching movies using Dvds ,listening to music using CDs and Mp3s. Computer is an electronic device that accepts ,stores and processes the data and returns the result or output
draft

Troubleshooting The Microprocessor

2009-05-09T23:29:00.000-07:00

Troubleshooting Microprocessor techniques solve the prolems that arisesdue to the improper functioning of the microprocessor.1) OverheatingA microprocessor produces heat while processing the data. The microprocessor also overheats when it is performorming beyond the recommended speed.Overheating can cause permanent damage to the microprocessor.To solve the proble of overheating:1. Check that the microprocessor fan is installed and functioning properly.2. Ensure that the heat sink compound is properly in contact with the processor and the heat sink assembly and is not dried up.3. Check the jumper settings on the motherboard and the BIOS settings to see that the microprocessor is not overlocked.4. Check that the voltage supplied by the motherboard is compatible with the microprocessor.5. Check the motherboard manual to see that the motherboards supports the microprocessor.2)Slow processing The microprocessor generally runs slow if there is some fault within it.To sole the Problem of slow processing:1. Check if the vendor has supplied the correct microprocessor.2. Check whether the microprocessor is compatible with the motherboard by reffering to the manual.3. Check the CPU fan whether its properly rotating.4. Check if the Microprocessor supports the applications that are running.5. Scan the computer for viruses.6. Check the jumper settings on the motherboard and the bios settings of the microprocessor.7. Troubleshoot the RAM.3) NO DisplayThe Computer can may encounter a problem of no diplay . This problem may be dure to processor failure. At this moment the system generates beep codes about the processor failure.You may have to replace the processor in sucjh a situation.To sole the problem of no display:1. Check whether the CPU fan is functioning properly.2. Ensure that tha processor with heat sink assembly is propwerly installed.3. Restore the BIOS seetting to default state and check whether the problem has been solved.MY Note: Replace the processor with the same specification. The speed, voltage , FSB and cache size of the new procezsoe should match with that of the old processor.

AGP Card of motherboard

2009-04-04T21:07:00.000-07:00

Accelerated graphic port (AGP) is an interface that is used to display graphics and 3D images in an efficient manner. An AGP card is installed into the AGP slot of the computer. It is a Point-t0-point Channel for attaching the graphics card. This card handles all the graphic effects of the computer. AGP offers high data transfer speed between the video chipset and the CPU.

Intel Introduced the first version of AGP namely 1.0 AGP cards available in different speeds are in below :

AGP 1 X - Uses a 32 bit channel for transferring data . It operates at 66 MHz and transfers data at 266 Mbps.

AGP 2 X- Uses a 32 bit channel for transferring data . It operates at 133 MHZ transfers data at 533 MBPs.

AGP 4 x - Opeartes at 266 MHz. It uses a channel of 32 bit channel to transfer data and can transfer a maximum speed of 1066 MBps.

AGP 8 X- Operates at 533 MHz. It uses a 32 bit channel to transfer data and the maximum throughout is 2133 Mbps.

AGP Cards are not always compatible with older AGP slots. UNiversal slots can handle different types of AGp cards . Agp cards operate in voltage of 1.5 to 3.3 volts .

Peripheral Componet Interconnect

2009-04-04T05:46:00.000-07:00

PCI is a bus standard developed by intel corporation. PCI slots are 32-bit wide in bus. This slot is used for attaching perpheral devices to the motherboard. Additional components such as Ethernet card and internal modem can be attached to the motherboard. This slots typically works at 33 MHz. However some newer variants are available that have a 64-bit wide bus and work at 33 MHz or 66 MHz. Data transmission Rate of PCI is 133 Mbps.

PCI Extended (PCI-X )
PCI Extended (PCI-X) is a standard designed jointly by HP, IBM and Compaq to increase the performance of high-bandwidth devices , such as Gigabit Ethernet and Fibre Channel.PCI- X is fully backward compatible with PCI and Data transmission rate is 1 GBPS. IT comes in Two variants. PCI-X 1.0 , with a maximum clock speed of 133 MHz , and PCI-x 2.0, with 533 MHz. BUt 2/0 also has other features like ECC ( Error Correction Code ) and 1.5 signalling.

PCI Express (PCI-E )
PCI express or PCI-E is the latest peripheral component interconnect special interests groups specification for the I/O bus. It is used for attaching peripheral devices to the motherboard. The PCI express extends the capabilities of PCi bus by having 32 differential pair of wires or lanes (X32) for high speed bidirectional serial data commucnication. It has point-to-point, hot pluggable and hot -swappable system bus that's fully compatible with PCI, atleast on the software level. Data transmission rate of each lane is 250 MBps. The initial version of PCI Express supports 0.8V signalling at 2.5 GHz. These wires can be combined to form bus architecture of x2, x4, x8, x16 and x 32.

PCI Extended

Expansion slots of Motherboard

2009-04-04T05:40:00.000-07:00

Expansion slots on a Motherboard enable you to connect expansion cards to the motherboard. The motherboard has three PCi Slots where you can connect PCI cards. The different PCI Cards include LAN card, Scsi card and USB card. The cards Must comply with PCI specifications. The PCI cards extend the capacity of the existing Motherboard. The AGP slot is used to attach a graphic card. The graphic card supports various graphic and display functions of the device. This card improves the graphic card functionalityof the system.

Keyboard and Mouse connector of Motherboard

2009-02-23T20:25:00.000-08:00

The keyboard and the mouse device are connected to the (personal system) ps/2 port of the computer. These ports are located at the back side of the system. The ps/2 port is a round shaped port usually located below the power supply of the system. The keyboard is usually connected to the PS/2 port or DIN 5 port and the mouse is connected to the serial or PS/2 port.The PS/2 port contains 6 holes and a notch in the middle of the port to which the keyboard and the mouse are connected.

Power supply connectors
Each power supply has special power connectors that connect to the motherboard which gives supply to the processor, memory and expansion boards. Attaching these connectors improperly can damage to both the motherboard and powersupply.

Serial and parallel port connectors
The most basic communication ports in any system are the serial and parallel ports and these ports continue to be important. Generally 9 pin serial port connector and 25 pin parallel port connector are used to convert various I/O devices.

Universal Serial Bus (USB)
The USB port is a rectangular port that is used to conncect a variety of external devices to the system. The USB port also supplies power to the device such as the Web camera, if the device does not use and external power source. To use the USB device yoy must just plug the device into the USB port , as most USB devices offer plug-and-play support.

Onboard connectors of Motherboard

2009-02-23T20:19:00.000-08:00

The hard drive floppy drive and the CD_ROM drive is connected to the motherboard using the on-board disk drive connectors. The primary connector used to connect storage devices such as the hard drive and the CD-ROM drive is the integrated Development Enviornmet (IDE) port on the motherboard. This is also known as the parallel Advanced Technology Attachment(PATA). The connector us a normal 40 pin connector. A 40 wire connector bus is used to connect the hard drive. Sometimes 80 wire connector bus is also used. The IDE 1 and the IDE 2 port on the motherboard is used to connect the hard drive and the CD- ROM drive respectively.

Motherboard Connectors

2009-02-23T20:13:00.000-08:00

Motherboard contains slots, sockets and connectors for connecting various devices. It contains slot for attaching RAM, graphic cards and any other device, and sockets for attaching the microprocessor. It contains super I/O chip, bus slots for connecting various peripheral devices. A CMOS battery is mounted on the motherboard to keep the system updated with latest date and time. An on-board CPU voltage regulator is provided to regulate power supply to the processor. You can configure the motherboard using jumpers.

1) Connectors
The different connectors on the motherboard enable connection of different devices. The different connectors on the motherboard are:

> System panel connector- Accomodates different front panel system functions such as system power LED, hard disk LED

> USB headers- Fuctions as connectors for USB module that can provide two additional USB ports, if the USB ports are inadequate.

> Digital audio connector- Connects to a module that provides digital sound output, instead of analog.

> MDC connector- connects to a modem card module.

> Internal audio connector- Enables a connection to CD- ROM or voice modem card.

> System management Bus (SMbus) connector- Used to connect SMBus devices.

> ATX 12 V connector- Connects the ATX 12 V power supply.

> Cpu and Chasis Fan connectors- Connects to the system cooling fans.

> SATA connectors- Connects to the SATA hard diskdrives,

> IDE Connectors- Connects to the IDE devices.

> Serial port connector- Accomodates a second serial port.

> Floppy disk drive connector- Connects to the floppy drive through the floppy drive ribbob cable.

How to Install RAM

2009-02-22T20:31:00.001-08:00

TO INstall DDR2 SDRAM

1. Wear an antiseptic wristband or hold a metal part of the chasis before touching any of the system componets.
2. Shut down the computer and disconnect the power cable from SMPS and peripheral devices attached to it.
3. Remove the computer cover
4. Remove the cards and internal components such as sound card or graphic card near the slot where RAM has to be placed. This helps to get easy access to the RAM sockets.
5. Hold the DDR 2 SD RAM module by the ends without touching the pins or chips .
6. Insert the module straight so that it is perpendiculas to the motherboard .
7. Close the side clips on DDR2 SDRAM.
8. Ensure that the clips are locked .
9. Replace all cards and internal components in a computer.
10. Reconnect the monitor, keyboard and mouse, but do not put the cover.
11) To check the amount of RAM, turn ON the computer. The first screen displays the amount of RAM installed or tou can check this from the BIOS settings.
12. If the amount of RAM is not right then turn off the computer and take out the DDR2 SDRAM module again.
13. Try to put it back in another sloy and reboot the computer.
14. shut down the computer and disconnect the peripherals again.
15. Put the cover and reconnect all the peripherals.

Form Factors of a motherboard

2009-02-22T20:05:00.001-08:00

Form Factors of a motherboard refers to its physical shape, layout and positioning of components on it. It also determines the type of system case it will fit into. Some motherboards that have the same functionality can be packaged in different form factord. The only major difference between such motherboards will be the form factor.

1)Obselete Form Factor

Obselete form factors consists of Advanced Technology (AT) , Baby At and low profile extended (LPX) form factors.

Baby AT Form Factor

Baby AT Form Factor is very much similar to the original IBM XT motherboard structure. The baby AT form factor fits into most of the system cases. A baby AT motherboard is 8.5 inches wide and about 13 inches long.

Advanced Technology (AT) Form Factor

AT Form Factor is also known as the full size At form Factor. This form factor matches the original IBM AT motherboard in structure and layout. This type of motherboard is very much large and is about 12 inches wide and 13.8 inches long.

Low profile Extended (LPX)

LPX and mini LPX form factors are used for small slim line or low profilr cases. This form factor was developrd by western digital , who no longer produces motherboards

2 )Modern Form Factor

Modern Form Factor consists of ATX, micro ATX, flex TX, mini ATX

Advanced Technolgy Extended (ATX) Form Factor

Intel invented the ATX form factor in the year 1965. ATX and mini ATX form factors are most popular and has many of the best featured of LPX and AT form Factors. This type of form factor supports maximum 7 slots. The main advantage is the single internal power supply connector.

New Low Profile Extended (NLX) Form Factor

NLX form factor is a new addition to the motherboard form factors. It was developed by intel and is similar to the LPX form factor.

MIcro ATX form factor

Micro ATX motherboards are small motherboards that are 9.6" in length as well as width. Low end pc users generally use this form factor.This type of form factor supports maximum 4 slots.

Definition of Motherboard

2009-02-20T21:02:00.000-08:00

Motherboard is the most important componet of a system. It is a printed Circuit Board ( PCB) Where all the components of a system are connected. The central processing unit (CPU), hard drives, memory and every other part of a system is connected to the motherboard by means of slots, connectors and sockets. The motherboard chipset is a series of chips that are a part of the motherboard. The chipset is very important to the operation of the system.

Types of Motherboards

2009-02-20T20:51:00.001-08:00

Motherboards and the capacity and efficiency of motherboards differ according to the type of system you use. Motherboards are classified as Interated and Non-integrated devices depending on the devices they support.

Integrated Motherboards
Integrated motherboards have all the peripheral device slots, input output ports , serial and parallel ports are mounted on the Board. The connectors for the various devices such as the hard drive connector and floppy disk drive connector are installed directly on to the motherboard. This arrangement saves a lot of space inside the system. Integrated boards are cheaper in cost as compared to non-integrated motheboards. The major disadvantage of these types of motherboards are that if an individual component of the motherboard fails, the whole board may need to be replaced.

Non-Integrated Motherboards
Non-integrated motherboards have RAM slots integrated on the motherboard. All the input-output ports for devices such as the serial and parallel port connectors, other controllers such as connectors for hard drive and floppy disk drives are attached to the system using expansion boards. Expansion boards use more space of the cabinet. If any one of the expansion boards fails, only those particular expansion board needs to be replaced and not the whole board. This type of board is more costly as compared to integrated motherboards as all the devices and ports, and other connectors for the devices need to be installed individually.

Overview of Memory

2009-02-20T20:45:00.000-08:00

1. Memory can be categorized into a Volatile Memory or a Non- Volatile Memory.

2. Volatile memory stores the data temporarily whereas the non-volatile memory stores the data Peramanently.

3. Physical memory divides the memory storage area into pages.

4. RAM is a semiconductor-based memory where the CPU or the other hardware devices can write the data and read the same from it.

5. Rom is the permanent storage device.

6. Prom stores the programs permanently.

7. EPROM uses the ultraviolet rays to remove the programs the memory.

8. EEPROM uses the electrical charges to remove the programs from the memory.

9. Logical memory stores data in the form of files.

10. Virtual Memory is part of the hard disk treated as a main memory.

11. Process of copying the pages from the hard disk to the main memory is known as paging or waping.

12. Process of converting the virtual addresses into the real addresses is called maping.

13. Flash memories are the high density devices that write data in chunks.

14. RAM is the main memory. The Static RAM and the Dynamic RAM are its two types.

15. Transistor or semiconductor device that opens or closes a circuit for reading the data.

16. SRAM uses around four to six transistors for each memory cell.

17. DRAM uses a pair of transistors and a capacitor for each memory cell.

18. EDO DRAM starts fetching the data from the next cell before the previous process completes.

19. VRAM stores the images that are to be displayed on the computer screen.

20. SDRAM synchronizes the memory speed with the CPU clock speed.

21. RDRAM transfers data at the maximum speed of 800 MHz.

22. DDR_SDRAM transfers data on both the edges of the clock signal that is on the rising and falling edges of the clock signal.

23. Processor accesses the data from the RAM in a random order with the help of the memory cell addresses.

24. Form factor is the size and shape of the memory package.

25. SIMM is a small circuit board designed to hold the memory chips.

26. SIMM package is Packed either in small outline J-Lead package or in Thin small outline package.

27. DIMM package is a small circuit board that contains the memory chips.

28. SODIMM package is used in laptops and notebook computers.

29. RDRAM package is used in the high bandwidth and the low latency applications.

30. Size of the data bus of the memory , error checking and correcting modules, and the parity and non parity of a chip are the characteristics of the memory.

31. Installation of RAM depends on the amount of the memory required for the processor and the configuration of the motherboard.

32. Memory of the system is upgraded either by changing the previous RAM or by adding one more RAM with the previous RAM.

33. Troubleshooting Methods are BIOS beep codes, Award Bios beep codes , Using PC memory Diagnostic software.

TroubleShooting Memory

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1) On switching on the machine , three beep tones are heard and then the computer stops or parity error is displayed on the screen.

Cause:- This problem may occur due to improper insertion of the Ram or due to defective RAM.

To solve the proble,:
1. Check all the memory modules you have installed.
2. Check for any loose connection.
3. If the problem is not solved then remove module one by obe, reinsert and check if the problem is solved.
4. If the problem is due to some defective memory module then replace with a new working module.

2) Wrong Memory Size

Cause :- IF the machine shows wrong memory size error on switching on, it could be due to wrong setup switch setting or wrong CMOS setup information.

To solve the problem:
1. Correct the setup switches.
2. Switch on the machine.

3) The memory card installed is not being recognized by the computer.

Cause:- This could be due to improper installation of the memory card.

To solve the problem:
1. Ensure that card is installed properly.
2. Ensure that memory chips are not defective.
3. Check that the settings on the motherboard are as given in the manual.

4) Pins of memory are dirty or slot is rusty.

Cause:- This could be due to dust in the memory connector and slot.

To solve this problem:
1. Clean them with student eraser and try again.
2. Clean the slot with brush.
3. Wash them with the pure alcohol and try again.

Troubleshooting Memory

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Troubleshooting memory using various methods can solve the memory problems. The beep codes and the memory diagnostic software are the ways to troubleshoot the memory.
Following are the Troubleshooting methods:
1) Using Beep Bios Codes
2) Using Pc memory diagnostic software

1) Using Beep Bios Codes
The BIOS program does the power on self test (POST) testing as the system turns on. This testing is done to ensure that the system is working properly. If the computer fails to start, a long beep is generated. This beep indicates that there is requirement to check the Bios of the motherboard for errors.

2) Using The BIOS Beep codes
Award is a BIOS developer . Award developer uses beep codes for recognizing the beeps when the computer boots up. If the computer boots up with one short beep then the computer is working fine. IF more than one beep occurs then there is some error. The following beeps that should be taken care are:
1 Long Beep- Shows the memory problem
1 Lone Beep and 2 short beeps- signifies failure of the DRAM parity
1 Long Beep and 3 short beeps- Signifies video error
continous beep- signifies failure in memory or video memory.

3) Using the Pc memory Diagnostic Software
Pc memory diagnostic software enables the user to solve the memory problems. For Example, Consider Doc Memory PC RAM Diagnostic Software. Thsi software can be downloaded from the internet to solve memory problems. IF the computer boots up properly but hangs after working for an hour, troubleshoot the memory using this software.

To Troubleshoot the Memory:
1) Download the DocMemory software from the internet.
2) Save the downloaded software to an empty directory on hard drive and double click the file to expand it.
3) INsert a blank diskette in the floppy drive.
4) Double-click the setup.exe to run the installation progran. A bootable diagnostic disc will be created.
5) Insert the disc in the floppy drive of the computer and restart the computer.
6) Edit the test patterns and other definable parameters.
7) Start the Quick test mode to run the diagnostic test on the memory.
If the memory shows and error such as incorrect memory sizing then there must be a problem with the software setting in the CPU. The error number for this error is 164. computer can use the DocMemory PC RAM Diagnostic software to fix this error. If the Memory diagnostic test does not show any error, check the motherboard, CPU , and other peripherals

Upgrading the Memory

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The memory of the system must be upgraded to increase the speed of the system. The memory is upgraded either by changing the previous RAM or by adding one more RAM with the previous RAM. The installation of a new RAM depends on the number of the free available memory slots on the motherboard.
Before installing a new RAM, check the type of RAM for mounting on the motherboard. The new RAM should match with the configuration of the previous RAm and should be supported by motherboard and processor.

Hands on Exercise

To Upgrade the memory of the system

1. Shutdown the computer and disconnect the power cable from SMPS and all the peripheral devices attached to it.
2. Remove the system Case.
3.Hold the RAM module by its edges. Do not touch the chips and connectors of the RAM Module,
4.Place the RAM module on the memory socket according to the type of the RAm. IF the additional Ram module is a SIMM, hold the Ram module in 45 degrees while placing on the memory socket.
5. Check the notches of the Ram module before placing it on the memory socket.
6. Put a slight pressure while inserting the RAM module on the memory socket.
7. Check the manual after inserting the RAM in the memory socket.
8. Put the case back to the computer.
9. connect all the peripheral devices to the computer.
10. Switch on the computer and check the current amount of the RAM

Types of Memory packages

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Memory package is a small circuit board that contains memory chips. SIMM,DIMM,SODIMM, AND RIMM are some of the memory packages. These packages are the form factors of RAM chip. The installation of a memory depends on the form factors of a RAM. A form factor is the size and shape of the memory packages.

Single In-line Memory Module ( SIMM)
SIMM is a small circuit board desingned to hold memory chips. It contains pins for accepting data from the control circuit. These circuit boards or modules are known as apckages. There are various SIMM packages available based on the number of pins it contains. For Example there are 30 pin packages and 72 pin packages.
The capacities of a 30-pin package SIMM package are 256 Kb, 1 MB, 2 MB, 4MB,8MB,16MB RAM. It contains 2,4,0r 8 chips per module. A 30-pin SIMM package has a data bus width of 9 bits with 9- bit parity . Parity checks the accuracy of the data transmission. An odd parity and an even parity are the two modes of parity checking.
A 72-pin SIMM package has 32-bit data width with 36-bit parity . PS/2 is another term used for the 72-pin package . The capacities of a 72- pin package are 1 MB, 2MB, 4MB,8MB,16MB,32MB,64,MB,AND 128MB RAM. It contains 2,4,8,or 16 data chips permodule. FPM DRAM uses a 72-pin package.

Dual In-line Memory Module (DIMM)
DIMM package is also a small circuit board that contains the memory chips. The difference between the SIMM and DIMM is that DIMM is a 168-pin package. The data of the DIMM packages are 64-bit ,72-bit, or 80-bit. A 168-pin DIMM package is available in thr SDRAM, EDO or FPM DRAM chips.

Small outline Dual In-Line Memory Module (SODIMM)
Laptops and notebook systems uses this package. It is the smallest version of the DIMM. The SODIMM package has a notch at the bottom of the circuit board. This notch helps in inserting the SODIMM package is the memory socket. SODIMM packages are available with 144 and 200 pins. A 144- pin SODIMM package has 64-bit data path. The FPM DRAM and EDO RAM use this package. The 72 pins on both the sides of the package divide a 144-pin package.
A 200-pin SODIMM package has 64-bit data path. PC2 100 memory and pc2700 memory use this package. The 100 pins on both sides of the package divide a 200-pin package .

Micro DIMM
Micro DIMM stands for MIcro Dual Inline Meory Module. This package is smaller than DIMM and SODIMM packages. The sub-notebook systems use these memory packages. The Micro DIMM package pins connect the memory module with the memory socket. These pins provide two communication lines for the module and the system. This Package does not have the notch at the bottom. Micro DIMM packages are vailable with 144 and 172 pins.

Rambus Inline Memory Module (RIMM)
RDRAM chip uses the RIMM memory package . This package is same as the DIMM package. It only differs in the pin configuration. The high bandwidth and the low latency application use this memory package .
The RIMM package has a data storage speed of 600 MHz, 711 MHz, 800 MHz and 1066 MHz. It has 184 connecting pins. The distance between each pn in the RIMM package is 1mm. This package starts opearting from 2.5 voltage supply. The RIMM package are available in 16-bit data buses 32-bit data buses, and 64-bit data buses. The memory bandwidth of the RIMm package is up to 9.6 GB per second.

Working of RAM

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RAM stores the data until the processor is executing the current data. Once the processor finishes the current execution, RAM forwards the next data to the processor.
The processor accesses the Data from the RAM is a random order with the help of the memory cell address. The cell addres contains the row number and the coloumn number of the memory cell. When the processor receives the data, it actually receives the memory cell address of the data. The RAM controller accepts the memory cell address. The RAM controller reads the data from the cell address and then sends the data in its respective address lines. The address lines contain the transistors and the capacitors for reading the data. The control circuit reads the capacitor when the transistors opens the cell. When the capacitor is charged , the memory cell returns a bit value as 1. When the capacitor is empty, the memory cell returns the bit value as 0.
In DRAM, each cell contains a pair of transistors and capacitor. Each cell represents a single bit of data in the binary format of 0 and 1. The capacitor stores the data in the memory cell. The transistor with the help of the memory control circuit reads these memory cells.A transistor acts as a switch. It turns on when the control circuit reads the capacitor. It turns off when the capacitor is empty. The DRAM Controller refreshes the capacitor after each reading of the memory cell. DRAM refreshes automatically. access speed of RAM is 80ns to 50 ns.

Types of DRAM

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1)Fast page Mode Dram (FPMDRAM)
Standard DRAM is accessed through a technique called paging. Paging enables faster access to all the data with in a given row of memory by keeping the row address the same and changing only the coloumn. Memory that uses this technique is called pagemode or fast page mode memory. This method was popular on 32-bit wide memory systems on486 processors but fell out of favor on pentiums because of their 64- bit wide memory widths.

2)Extended Data out DRAM (EDO DRAM)
Extended Data out (EDO) DRAM is a type of asynchronous Dram. It is also known as hyper page Mode DRAm. It is faster than Normal DRAM. This is because EDo DRAM starts fetching the data from the next cell before the previous process completes.

3) Synchronous Dynamic Random Access Memory ( SDRAM)
SDRAM synchronizes the memory speed with the cpu clock speed . The speed of the SDRAM depends on the speed of the cpu bus. It is faster than SRAM, DRAM. EDO DRAM and VRAM memories. The data transfer speed of SDRAM is measured in nanoseconds and megahertzunits. It runs with an average speed of 133 MHz.

There are two modules of SDRAMs :
> 2-clock SDRAM- In a 2-clock SDRAM , each clock signal controls two different DRAM Chips.
> 4-clock SDRAM - In a 4-clock SDRAM , each clock signal controls four different DRAM chips. The recent computers use 4-clock SDRAM.

4 ) DDR1 And DDR2
DDR DDR2

Data Bus 64 bits 64 bits
Dat Rate 200/266/333/400 MHz 400/533/667 MHz
DRAM Frequencyn 100/133/166/200 MHZ 200/266/333 MHz
Density 128 MB to 1 GB 256 MB to 4 GB
Voltage 2.5 volts 1.8 volts

Types of RAM

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Ram is the main memory of the computer. It holds the data until the system is turned off.once the system is switched off the data is lost. There are two types of Ram , Static RAM and Dynamic RAM.

Static Random Access Memory(SRAM)

1) Stores data till the power is supplied

2) Uses an array of transistors for each memory cell.

3) Does not need refreshing the memory cell after each reading of the transistors.

4) Data access is faster

5) Consumes more power

6) It is Expensive.

Dynamic Random Access Memory (DRAM)

1) Stores data only for few milliseconds even when power is upplied.

2) Uses a single transistor and capacitor for each memory cell

3) Needs refreshing the memory cell after each reading of the capacitor

4) Data access is slower

5) Consumes less power

6) Less Expensive

Memory

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Memory is one of the functions of the brain that enables to store and remeber the past events. Similarly, in Computers the term memory refers to a chip that stores data. It also enables us to retrieve the stored Data. The processor retrieves information stored in the memory for processing Data. The storage capacity of a memory depends on the type of the memory package used.

Types of Memory

Memory can be divided into two types, Volatile memory and non volatile memory. Volatile memory temporarily stores the data. It loses data as soon as the system supply is turned off. Non-volatile memory stores data permanently.It does not lose the data even if the system supply id turned off.

Further, Memory is classified into physical memory, logical memory, virtual memory and flash memory.

Two types of physical memory

RAM - Stands for Random Access Memory. It is a semiconductor-based memory where the cpu or the other hardware devices can read and write data. It temporarily stores the data and it is a volatile memory.Once the system turns off, it loses the data. As a result, Ram is used as a temporary storage area.

ROM - Stands for Read only Memory. It stores the Data permanently and it is a non volatile memory. It does not lose data even after the system turns off. As aresult rom is a permanent data storage area.

Logical Memory

Logical memory enables the user to use large amount of memory to store data.It defines a way to organize the physical memory such as RAM and cache. This enables the operating system to arrange memory into a logical manner such as asssigning a logical address. Logical address is a memory location and it is accessed by an application program. The system maps the logical address to real physical storage address.

Virtual Memory

Virtual memory is a part of the hard disk which is used as a memory . It has a set of memory addresses and stores the instruction or the data. When the processor exuxutes the instructions it converts the virtual memory addressed into real memory addresses. The main use of the virtual memory is to increase the address space.

Flash Memory

Flash memory is the high-density device. It is a non volatile memory. It is fast in reading and writing data. This is because it writes data in chunks or blocks. Flash memory is an electrically re-programmable device. The contents from the flash memory are erased in blocks and not in bytes. The block size can range from 256 bytes to 16 kB . Flash Memory can replace hardisk in portable computers. In this context, flash memory is available as pc card that you can plug into the PCMCIA slot.

Cache Memory

Cache memory is a small and fast memory which is placed between the CPU and RAM.It is acessed at a very high speed than the system memory. As a result, the programs which acess the same data or instructions over and over run faster. The cpu does not have to transverse to the main memory to get the data . It will first acess the cache to find the data.