WorkStation Care

Identifying General System care factors. Environmental factors Power factor Environmental Factors Temperature Humidity Dirt & smoke Electromagnetic interference (EMI)

Original Operating Installation CD. Original SOftware CD : Microsoft Office suite CD Various Driver Installation CD's Motherboard CD Anti-virus Program CD Documentation CD,s for OS & each of the above mentioned software utilities.

The Rescue disk is the floppy disks that is used to start a computer when the hard disk fails to boot. The rescue disk also contains driver files that are required to load a CD-ROM drive. Hence you can also use rescue disk to start a computer in case computer fails to boot from the CD-ROM drive. A Rescue disk is created for each computer in service. This is because a rescue disk contains computers configuration information that is unique for each computer.

The minimum set of files that are required for creating a windows NT4.0, or Server 2000/2003 boot floppy disk are: BOOT.INI NTLDR NTDETECT.COM The minimum set of files that are required for creating a windows 95/98/me boot floppy disk are: COMMAND.COM FORMAT.EXE (FORMAT.COM) SYS.COM MSCDEX.EXE MSD.EXE (MSD.COM) FDISK.EXE (FDISK.COM)

In addition to hardware tools, a computer technitian should carry certain software that is normally required for troubleshooting. Bootable floppy disks. Rescue disks. Some software utilities.

Electrostatic Discharge (ESD) damage occurs when a stored static electricity travels from something such as a persons body into a conductor of a computer being repaired. Hence, to prevent from ESD damages a computer technician also have some ESD protection tools. Anti static wristband Anti static Mats Anti static bags

A computer technician should also have a can of compressed air in his/her toolkit that is very useful in removing dust from computer component.

This tool is used for changing video RAM & other older RAM,s that are plugged into sockets.

This tool is used tp piking up very small objects like small screws that are inconvenient to pick with human hand.

Screw Driver Torx driver Nut driver Tweezers Neeble-nose pliers chip removers compressed air ESD Tools Multi meter Flash light Hemostats POST Card Small-Plastic container Laptop, Floppies & CO-ROM folder

In hibernate mode, The entire content of the memory is written onto a special file called swap file & then the system is shutdown. When reactived, the file is read back to memory. The disadvantage of hibernate mode is that it takes more time to reactive a system than suspend mode, but the advantage is that is saves on battery.

To provide the expandability to laptop computers, a special type of expansion cards are used in laptops called the PCMCIA (Personal Computer Memory Card Inter nation Association) card. These cards are also called PC cards. The four PCMCIA types: Type 1 Type 2 Type 3 Type 4

This is used in laptops work in the same way as those that you have seen in bank ATM's. Here the screen display several buttons, you have touch the location specific to a button in order to select an item from the menu. Touching the screen button gives the same result that you will get by double clicking an item on the screen using your mouse.

Touch Pad is also called Track Pad is a recent development in the input devices for laptops. It was developed to overcome the limitation of trackball. It consists of a electromagnetically sensitive rubber Pad (dimension 1inch * 2inch) which is sensitive to touch of a finger.

It is also called Track Point or higher mouse. It was introduced by IBM in their Thinkpad laptop series It is a small stick with a rubber tip(0.25inch) located above letter B & below G & H on the laptop keyboard.

This is used in earlier laptops. It is a small ball(0.5inches) that is inserted in the keyboard itself. You can move the ball, using your finger or thumb, to move the onscreen courser in the specified direction. In addition, you can use the click button to select an item on the screen.

Laptop keyboards usually have a much lower number of keys than normal computer. Laptop Pointing devices: Track ball. Touch point. Touch pad. Touch screen.

Laptops because of their smaller size use storage devices much smaller in size than desktops. For instance the hard disk drives uses in laptops are about 2.5inches wide & 1/2inches thick & it has smaller connectors. It is much smaller than 3.5inches HDD's used in desktops.

Laptop LCD screens are classified into two categories : Active matrix & Passive Matrix displays.

Laptops use smaller memory modules that fall into two main categories: 5001MM & Micro DIMM have 144-or 172-pin configurations & supports 64-bit data bus. They have a category of 1GB. But they are more expensive than SODIMMS. Laptop RAM

laptops mostly run on battery when not getting supply from the mains, however when connected to mains on AC adapter is used to supply DC power to the Laptop. This adapter is also responsible to charge the battery side-by-side as long as the laptop is connected to the mains. Batteries come in a verity of shapes & size, depending on the make & model of the laptop. Most laptops use Nickel Cadmium(NiCd), Nickel Metal Hydride(NiMH) or Lithium-ion(Lilon).

Most laptop processors are soldered directly in the motherboard, which means they cannot be removed. If there is some error in laptop processor, the entire motherboard needs to be replaced. Laptops processors can be slowed down when they are not running to their full capacity. The processor uses a technique called processor trotling that allows the operating system to put the processor in active sleep mode or shutdown mode. Laptop processors run at reduced clock rate than desktop processors. This helps them to produce less heat when running at full capacity. Laptop processors consume less power which though make them a slow performer but it greatly helps them to save battery life.

Core 2 Duo (mobile version) Intel Centrino Duo AMD turion 64 & turion 64*2 Transmeta crusoe & efficeon

It is also called palmtops or hand helds even smaller than the notebook laptop computer. They are just of the dimension 7inches *4inches *1inch. Because of such a small size, they often have limited functanality.

It is similar than laptops. Its size is roughly 8.87 inches *11inches *2.25 inches.

A small, portable computer small enough that it can sit on your lap. laptop computers weights 1 to 8 KG.

The term "Portable" means "moveable". Therefore a portable computer can be defined as a computer that can be moved from one place to another to another. The portable computers are also known as mobile computers. Three basic types of portable computers: Laptop Notebooks subnotebooks

Gateways provide all connectivity of, & even greater functionally than routers & bridges. A gateway usually resides on a dedicated computer that acts as a translator between two completely dissimilar systems or applications because gateway are both translators & routers, Gateways also provide access to special services such as e-mail or fax functions.

Bridges work like repeaters, but offer additional advantages. They can isolate network traffic or pproblems. Should any problems occurs with in one segment the bridge will isolate that segment & not affect other segments on the network, there by reducing the load on the network as a whole. Bridges can also link segments that are not alike (such as Ethernet & token ring )

A repeater works like an amplifier to increase or boost the signal to allow transmissions over longer distances. Repeaters used to connect network segments.

Repeaters Bridges Routers Gateways

IPX/SPX - Inter work packet exchange / Sequenced packet exchange . NetBIOS/Net BEUI - Networked basic input output system / NetBIOS enhanced user Interface . TCP/IP - Transmission control protocol / internet protocol . Apple talk . DLC - Data link control protocol .

A network Protocol is a set of rules that govern the way computers communicate over a network. For computer using different software to communicate, they must follow the same set of networking rules & agreements called protocols. A Protocol is like a language, unless both computers are speaking & listening in the same language, no communication will take place.

A token Ring network uses a token as the basic for desiding who can communicate on the network. Token rings transmit at 4 or 16 Mbps.

Ethernet uses a system known as CSMA/CD (Career Sense Multiple Access With Collision Detection). The term carrier sense means that the network card listens to the cable for a quiet period during which it can send messages. Multiple access refers to the fact that more than one computer can be connected to the same cable. collision detection is the ability to detect whether messages have collided in transit.

Fiber Optic Cable is made up of light-conducting glass o plastic fibers. It can carry data signals in the form of modulated pulses of light. Fiber has some advantages over copper wire. It is immune to EMI (Electro Magnetic Interference) & detection outside the cable & provides a reliable & secure transmission media.

Coaxial Cable is made up of two conductors that share the same axis. The center is a copper wire that is insulated by a plastic coating & then wrapped with an outer conductor. This outer conductor around the insulation serves as electrical shielding for the signal being carried by the inner conductor. A tough insulating plastic tube outside the outer conductor provides physical & electrical protection.

Twisted-Pair consists of two insulated stands of copper wire twisted around each other to form a pair. One or more twisted pairs are used in a twisted pair cable. The purpose of twisting the wires is to eliminate electrical interference from other wires outside sources such as motors. Twisted-Pair wiring comes in two pages. STP (Shield Twisted Pair) & UTP (Un shield Twisted Pair ). STP has a fail or wire braid wrapped around the individual wire of the pair UTP does npt. To reduce the electrical interference the wires are twisted.

Twisted-Pair cable Coaxial cable Fiber Optic Cable

NICs link a computer to the network cable system. They provide the physical connection between the computers expansion bus & the network cabling. Low power digital signals that transmit data inside a computer are not powerful enough to travel long distances. An NIC boosts these signals so they can cross a network cable.

The NOS consists of a family of programs that run in networked computers. Some programs provide the ability to share files , printers & other devices across the network. Computers that share their resources are called servers; Computers that use the resources on other computers called clients. It is common to run client & server software on the same computer. This enables you to access the resources on another computer while coworkers make use of resources on your computer.

Advantage: Less cable Required. Disadvantage: If one system is failed whole network will be failed.

Advantage: It requires less cable. Easy to extend our network. Easy to implement. If one System is damaged the others will work. Disadvantage: Slower the access. If cable is broken some systems will not work.

Advantage: Easy to implement. If one System is damaged the others will work. Disadvantage: If HUB is damaged the whole entire network will be failed. It requires lots of cable.

LAN design is called topology. Which describes the appearance of layout of a network & how data flows through the network.

A computer system that serves as a central repository of data and programs shared by users in a network.

Networks can allow computers, servers, and other devices to talk to each other. There are a number of different types of networks, and it's important to find the right one to fit your needs so that you don't waste time and money with one that is too complex for your needs, or one that doesn't fulfill your needs. In a peer-to-peer network there are no dedicated servers or hierarchy among the computers. All of the computers on the network handle security and administration for themselves.

A WAN spam relatively large geographical areas. connections for these sites require the use of ordinary telephone lines, T1 lines,ISDN (Integrated Service Digital Network) lines, radio waves, cables or satellite links. WAN's can be accessed through dial-up connections using a modem or leased-line direct connection. The leased-line method is more expensive but can be cost effective for transmission of high volume of data.

LAN is a network that covers a limited distance(usually a single site or facility) & allows sharing of information & resources. A LAN can be as simple as two connected computers or as compliated as a large site connecting many computers. Resources that can be shared over a LAN. Data Peripherals Software Storage

A network is defined as two or more computers linked together for the purpose of communicating & sharing information & other resources. Basic Requirements Of a Network: Connections The network medium The network interface Communications. Services. Types of Network LAN ---> Local Area Network WAN--->Wide Area Network MAN--->Metro Politen Area Network PAN --->Personal Area Network

Optical Mark Recognition is the process of capturing data by contrasting reflectivity at predetermined on a page. Light is used to detect marks on a sheet of papers. Scanning speed is approx 2300 sheets per second.

Hand scanners are manually devices that are dragged across the surface of the image to be second. Light on the scanner would indicate if the motion was too fast. Most hand scanners were monochrome.

Drum Scanners get their name from the glass cylinder, or drum, that the image to be scanned is mounted on. In the middle of the drum is a light-splitting sensor which breaks the light bounced from the document in to red, green & blue components. these color beams are sent to a photo multiplier tube or charge coupled device (CCD), where the light beam is converted to an electrical signal. Electrical signal is then sent to monitor by a cable where we see the scanned image.

The Scanner is an input device. That can be used to copy the entire image of the hard copy(paper). Types of Scanners Drum Scanner Flatbed Scanner Hand Scanner Slide Scanner Optical Mark Reader (OMR)

Seven steps involved in the laser printing process. 1. Raster Image Processing 2. Charging. 3. Writing 4. Developing. 5. Transfering. 6. Fusing. 7. Cleaning

It was invented in 1969. Also known as page printers. High resolution range from 300 to 1200 DPI. Fastest model can print 200 pages per minute. Color printer can print 100 pages per minute.

A type of printer that works by spraying ionized ink at a sheet of paper. Magnetized plates in the ink's path direct the ink onto the paper in the described shapes. There are three main technologies in use contempory inkJet printers: Thermal, Piezoelectric & continuous. High quality output. High resolution of minimum 300 Dots Per Inch (DPI). Ink is expensive. InkJet cartridges can be refilled. HP pushes InkJet printing to 70 pages per minute.

Pen-Based plotter are restricted to line art. Very slow because of mechanical moment of pen. A number of printer control language were created to send the more detailed information. The two common ASCII based plotter control languages are Hewlett Packard's HPGL2 or Houston Instruments DMPL.

A high speed printer capable of printing on entire line at one time. A fast line printer can print as many as 3000 lines per minute. They cannot print Graphic. The print quality is low, & they are very noisy.

The Daisy wheel is a disk maded plastic or metal on which characters standout in relief along the outer edge. Daisy wheel printers cannot print graphics. They are noisy & slow. Printing form 10 to about 75 characters per second .

Concept of head. Can create carbon copies. Dot is produced by a tiny metal rod, also called a "pin" commonly 9 or 24 pin. Early Dot-Matrix Printers. LA 180 - 180 C/S (contact per second) LA 120 - 120 C/S LA 30 - 30 C/S

A computer printer produces a hard copy of documents stored in electronic form, usually on physical print media such as paper. Classes of Printers The two classes categorized as impact & non-impact printers. 1.Impact Printers Dot-matrix Printer Daisy wheel Printer Line Printer Pen based plotter 2.Non-Impact Printers InkJet Printer Laser Printer Inkless Printer Photo Printer

Considerations LCD CRT Size Compact Bulky Image flicker Low(20W depends upon size) High(150W depends upon size) Heat emission Low High Weight Light Heavy Color range Good Excellent Cost Approx 400rs higher then CRT of same dimensions Cheap

Technology behind LCD concept of liquid crystals & filters. Passive-matrix displays (PMDs) : PMDs are the simplest & they been used in calculators & watches since 1970. Active-matrix displays: Active-matrix displays use TFT’s (Thin Film Transistors;TFT also described this type of display) at each pixel to control each pixel’s on off state.

A type of thin display screen called a flat-panel display. Used in some older portable computers. A gas-plasma display works by sandwiching neon gas between two plates. Plates are coated with a conductive print. The print on one plate contains vertical conductive lines & the other plate has horizontal lines. Together, the two plates from grid. When electric current is passed through a horizontal & vertical line, the gas at the insertion glows, creating a point of light or pixel. You can think of a gas-plasma display as a collection of very small neon bulbs.

Used in traditional computers. Concept of electron guns: The rear of the CRT holds cylinder that contains one or more electron guns. Most color monitors have three guns in back one of the colors Red, Green & Blue (RGB). This allows the visual production of all colors. Phosphor Coated Display Screen: The guns beam a steam of charged electrons onto the phosphor coating. When the coating is hit with the right amount of energy. Light is produced in a pattern of very small dots. There is one dot for each primary color (RGB), & the dots are grouped in patterns close together. The name for a collection of all dots in a specific location is a pixel (which stands or picture element). Image formation & refresh rates. Persistence Rate: How long the phosphorus on the screen remain excited & emit light. Vertical Refresh Rate: The time required to complete a vertical pass. Horizontal Refresh Rate: The time required to pass once from left to right.

Monitor is an output device which displays the output by displaying the image generated by computer. Types of monitors: CRT LCD Gas plasma

IRQ 0 - System timer IRQ 1 - Standard 101/102-Key or Microsoft Natural PS/2 Keyboard IRQ 3 - Communications Port (COM2) IRQ 4 - Communications Port (COM1) IRQ 8 - System CMOS/real time clock IRQ 9 - Microsoft ACPI-Compliant System IRQ 11 - Intel(R) 82801G (ICH7 Family) SMBus Controller - 27DA IRQ 12 - PS/2 Compatible Mouse IRQ 13 - Numeric data processor IRQ 14 - Primary IDE Channel IRQ 15 - Secondary IDE Channel

IRQ's are hardware lines over which devices can send interrupt signals to the microprocessor. When you add a new device to a PC, you sometimes need to set its IRQ number by setting a DIP switch. This specifies which interrupt line the device may use. IRQ conflicts used to be a common problem when adding expansion boards, but the Plug-and-Play specification has removed this headache in most cases.

FireWire use peer to peer architecture. USB use "Master Slave" architecture.

IEEE 1394 Fire Wire High Performance Serial Interface Shortly called as 1394. This high-speed serial interface allows up to 62 devices on chain, at data transfer rates up to 50MBPS. Advantages: A hot Swap technology. Simple cable Design. IEEE = Institute of Electric & Electronic Engineering.

PCI Express is a expansion slot that is becoming the new standard for high speed internal graphic cards. PCI Express slots come in several types defined by the number of lanes the slot has to communicate with described as x1, x2, x4, x8, x16 & x32. The most commonly found types inside the current computers are the x1 & x16. Graphics cards are available that will run on both x1 & x16 cards however, alll high performance graphic cards use the x16 slot.

AGP 1x mode is the oldest. It transfers data at 266MBPS. AGP 2x mode transfers data at 533MBPS. AGP 4x mode transfers data at 1.07GBPS. AGP 8x mode is the latest. It transfers data at 2.14GBPS.

If u having more cards on a single bus it slow down the performance. This is the problem for display designers. To solve this problem AGP has introduced. The AGP removes all the display data traffic from the PCI bus gives that traffic its own 535MBPS pipe into the system chipset. The Brown colour one is AGP

CNR is a specification that supports audio, Modem USB & local area Networking interfaces of core logic chipsets. This Technology was 1st introduced by Intel on February 7th 2000 .

Released on 8th september 1998, AMR allows OEM,s(Original Equipement Manufacturer) to create one card that has the functionally od either modem or audio or both on one card. MODEM(Modulator & Demodulator) OEM(Original Equipment Manufacturer)

The PCI designs special bus & chipset are designed for advanced bus mastering techniques & full arbitrations of the PCI local bus. This allows support for more than 3 slots. It has its own set of four interrups which are mapped to regular IRQ's(Interrupt Request) on the system. At full performance, the PCI bus can deliver data transfers at upto 132MBPS. PCI slot support for plug-n-play architecture.

Both are local bus systems with 32 bit paths & brust modes. PCI operate at 33MHz which is roughly the same speed as the VLB.

PCI is short for "Peripheral Component Interconnect" PCI slots allow numerous different types of expansion cards to be connected inside a computer to extend the computers functionality. Local bus systems with 32 bit paths & brust modes. It operates at 33 MHz.

Burst Mode: VLB devices gain complete control of the external data bus up to four bus cycles. It passes 16 bytes of data in a single burst Burst Mastering: It allows the VLB controller to arbitrate data transfers between the external data bus & 3 VLB devices without assistance from the CPU.

It was developed to meet the need for a faster expansion interface. It was found only in 386 & 486 machines. The chip designed for the VLB controller was relatively simple because many of the core instructions were hosted by the ISA circuits already on the motherboard but the actual data passes were on the same local bus as the one used by the CPU.

It was released in 1988 having 32bit data bus & 8MHz. It is an improved Version of ISA slot that accepts older ISA cards. It have all features of MCA like Bus Mastering, Intelligent Data Bus. Advantage ESIA is faster & cheaper than MCA Disadvantage scope for limited number of cards that run at the faster rate

In 1986 the new 386 machines came with 32 bit architecture. A new version of personal system/2 (PS/2) & created a preparatory expansion bus called MCA as part of the design. It runs at 10 MHz & provided 32bit data path Advantage: MCA is a "Self Configured" device. Supports "BUS Mastering". Disadvantage: It is not compatible with older ISA card.

The 1st IBMXT with the 8088 processor had an 8-bit external data bus & run at a speed of 4.77MHZ. IBM released the AT(Advanced Technology), PC with 80286 processor had an 16-bit processor. The designers added a bus that allowed insertion of either an 8-bit card or one 16-bit card. The change was made in the standard 16-bit slot. Thus new 16-bit bus officially run at a top speed of 8.33 MHz.

ISA (Industry Standard Architecture) MCA (Micro Channel Architecture) EISA (Extended Industry Standard Architecture) VESA local bus (Video Electronics Standard Association) PCI (Peripheral Component Interconnect) AMR (Audio Modem Riser) CNR (Communication Network Raiser) PCI-X (Peripheral Component Interconnect Extended) AGP (Accelerated Graphic Port) PCIE (Peripheral Component Interconnect Express)

Expansion bus devices to the motherboards data bus. They allow the flow of data between internal & external devices.

When the system is first purchased, it can certain features which you can further expand by using special circuit board called Expansion Slots. These expansion cards are inserted in to designated locations specified on the motherboard. The spaces on the motherboard where the expansion cards are inserted & called Expansion Slots.

RAM above the 1MB address is called extended memory. Exteneded memory is accessed through an extended memory manager (HIMEM.SYS).

HMA is the first 65,520 bytes (64KB less 16 bytes) of extended memory. It is speciall because it is an only part of extended memory that can be used by the PC while operating in real mode. MS-DOS loads portion of its code in it , so other application can use area below 640KB. A software driver called an A20 handler must be run to allow the processor to access the HMA.

The Upper Memory Area(UMA) the memory block from 640KB to 1024KB, is designated for hardware use, such as video RAM, BIOS. First 128KB are called video RAM, it is reserved for video adapters, all bits used for graphics & images are stored in it. Second 128KB is reserved for BIOS that resides in ROM chip of some adapter card. Remaining is used by SCSI, ATA RAID, & SATA adapters with onboard BIOS chips, use a portion of this area to store their BIOS's. The last 128KB of memory is reserved for motherboard BIOS.

It is the amount of RAM typically 640KB(start from memory address 00000h) addressable by machine operating in red mode. Available for use by DOS program device drives , memory resident programs & application that run under DOS.

How the memory is allocated for use by the CPU is called memory mapping. Memory mapping is logical layout of RAM is still a single chip.

All computer memories is used to hold binary strings of data to be manipulated by the CPU. Memory refers to a chip that stores data. The processor retrieves the information stored in the memory for processing the data.

Backup important data. Record the current BIOS configuration, especially harddisk settings. Before beginning a flash BIOS upgrade, you must determine where to get your BIOS upgrade. The first thing you need before you begin the flash upgrade software for your motherboard . An upgrades is not found at AWARD BIOS, AMI BIOS or Phoenix BIOS website. simply write down the version of your BIOS. Download the correct BIOS upgrade for your system or motherboard. Install the BIOS upgrade loader & BIOS image to a floppy disk. After installation is complete , some upgrades run automatically; other requires that you choose the image from a menu, & prompt you to save your current BIOS image to a floppy disk. After the updated process starts, it takes about three minutes to re wright the contents of the BIOS chip with the updated information. Remove the floppy disk & restart the system to use your new BIOS features.

Most systems sold since 1995 have flash BIOS chips that can be upgraded with software. Why we upgrade BIOS ? New Hardware such as large IDE HDD's & removable storage devices. Faster CPU's. New Operating Systems & features such as Windows 98, XP, NT, & Vista.

Its also known as ICH (Input Output Controller Hub). It is the another controller chip on the motherboard which controls the slower devices like PCI, USB, IDE, BIOS etc.

In Intel systems some times also reffered as MCH (Memory Controller Hub) . Some chips contain Graphic controller also (GMCH) Its job is to control the communication Between processor, RAM, AGP, PCI express, & the South bridge.

-12 : Required for some SERIAL ports -5 : For Floppy controllers 0v : Ground +3.3v : Computer memory +5v : For Processor, mother boards & other system +12v : For Disk drives, fans & cooling devices

SMPS consists of high frequency switch which is actually transistor with frequency range 50 khz to 1 mhz. The switch is used to control & stabilize the load current on & off. It converts AC to DC. Similar size, great power conversion, reduse over all power loss & generates low heat. Disadvantage. It generates more noise & more complex.

It is power supply that is used for products that consume less power, require wide I/P voltage range, low noise & fast response. Disadvantage: Poor efficiency. Huge in size that used in external power supplies like answering machines, cordless phones, etc. example: Adapter

A Ferro-resonant power Supply, also called constant voltage transformer (CVT), it is low cost Power Supply that is used to provide reasonable O/P voltage at high power levels. It is a highly reliable power supplier because of its simple circuit design. It provides constant Voltage.

A power supply is an electronic circuit that process electrical power to convert it from one form to another form. General need for a PC is 130-350 watts . Servers & High Performance work stations need 350-400watts. Types Of power Supplies: Ferro-Resonant Power Supply Linear power Supply Switch Mode Power Supply (SMPS)

It is also called "RAID 03" or "RAID 30" combination of RAID 0 & 3 . Advantage: High data Transfer rate & high I/O rate. Disadvantage: Expensive.