Maintenance of Computer System OVERVIEW ECE Government Polytechnic, Nilokheri

Computer Hardware Maintenance Outline: Introduction to computer hardwares Basic operations Motherboard Processor RAM & ROM Ports & Cabling Connectors & Expansion Card Storage & Hard Drives Power Supply Types of printers

Graphic Representation of Computer Components:

Motherboard The motherboard is the main circuit board of a microcomputer. It contains the central processing unit (CPU), the Basic Input/Output System (BIOS), memory, mass storage interfaces, serial and parallel ports, expansion slots, and all the controllers for standard peripheral devices like the keyboard, disk drive and display screen. BIOS stands for Basic Input/Output System. It is the lowest-level software in the computer; it acts as an interface between the hardware (especially the chipset and processor) and the operating system. The BIOS provides access to the system hardware and enables the creation of the higher-level operating systems that you use to run your applications. The BIOS is also responsible for allowing you to control your computer's hardware settings, for booting up the machine when you turn on the power or hit the reset button, and various other system functions.

ATX MOTHERBOARD ATX

Further research: Buses, System Bus, Expansion Bus Inside the Processor The CPU has 2 fundamental sections: the Control Unit, and the Arithmetic Logic Unit. These work together to perform processing operations. Fundamentally all processors do the same thing. They take signals in the form of 0s and 1s (thus binary signals), manipulate them according to a set of instructions, and produce output in the form of 0s and 1s. The voltage on the line at the time a signal is sent determines whether the signal is a 0 or a 1. On a 3.3-volt system, an application of 3.3 volts means that it's a 1, while an application of 0 volts means it's a 0. Other components of the CPU include the Registers and the System Clock. A processor’s clock speed is measured in Megahertz (MHz) and Gigahertz (GHz). Clock speed is the speed at which a processor executes instructions. A Pentium IV typically has a clock speed of 1.4 GHz. Further research: Buses, System Bus, Expansion Bus

Random Access Memory (RAM) RAM is Primary Storage, also called internal storage. Serves as computer’s workspace, storing all or part of the program that is being executed, as well as data being used by the program. RAM stores the operating system programs that manage the operation of the computer. RAM is Volatile storage: Power goes, data goes! More memory = larger workspace Large programs = large number of instructions Measured in Bytes (KB, MB, GB, etc.) Data/instructions are copied into memory as needed. Not enough memory or corruption of data/instructions in memory can cause crash. LATEST AVAILABLE RAM ID DDR4 CATEGORY

BIOS EEPROM chips contain permanently written data, called firmware (your BIOS lives here). EEPROM contains the programs that direct the computer to load the operating system and related files when the computer is powered on. EEPROM chips are usually recorded when they’re manufactured. Flash memory is reprogrammable memory. You can upgrade the logic capabilities by simply downloading new software. This saves the expense of replacing circuit boards and chips.

PORTS On computer, a port is generally a specific place for being physically connected to some other device, usually with a socket or plug which we call Connectors Typical Computer Port found behind a desktop PC

CONNECTORS A connector is any connector used within computers or to connect computers to networks, printers or other devices. Many types of computer connectors

PS/2 Connector The PS/2 connector are use for connecting keyboard and mouse on the modern PCs. The PS2 mouse connector and port is usually green in colour to distinguish it from the PS2 keyboard, which is purple. It is 6 pin round shape connector

USB Port Universal Serial Bus: a protocol for transferring data to and from digital devices. Many digital cameras and memory card readers connect to the USB port on a computer. It is also known as Hotswappable port

Firewire IEEE 1394 Port A type of cabling technology for transferring data to and from digital devices at high speed. FireWire are typically faster than those that connect via USB.

RJ45 Ethernet Port LAN or (Local Area Network) uses a CAT6 cable and a RJ45 connection. The CAT 6 cable  is also called the Ethernet Cable. Network connection generally uses a 10/100 Mbps/1Gbps speed.

DB25 Parallel Port The printer connects to computer with a Parallel connector. This connector has 25 pins. Parallel means the device is capable of receiving more than one bit at a time (that is, it receives several bits in parallel). It is also termed as LPT

Ports and Connectors

Expansion Cards Accelerated Graphics Port (AGP) Expansion Cards plug into the expansion slots found on the motherboard. Convenient way to add extra ports or expand the computer’s capabilities. Accelerated Graphics Port (AGP) Peripheral Component Interconnect (PCI)

Expansion Slots and Cards Various type of expansion slots are: Peripheral Component Interconnect (PCI) Accelerated Graphics Port (AGP) Industry Standard Architecture (ISA) (obsolete category) Universal Serial Bus (USB) Small Computer System Interface (SCSI) Integrated Drive Electronics (IDE) Expansion slots are sockets to provide direct connections to the common electrical bus, allowing you to insert a circuit board into the motherboard. Typical Expansion Cards: Video Cards Sound Cards Modem Cards Network Interface Cards (NIC) PCI and PCI-e are the latest architecture used in todat computers

Printers Impact Printers Non-Impact Printers Daisy wheel Dot- Matrix Inkjet Laser

What is a printer? An external hardware device responsible for taking computer data and generating a hard copy of that data. Printers are one of the most commonly used peripherals and they print text and still images on the paper.

“Impact Printer Working” These printers have a mechanism that touches the paper to create an image. These printers work by banging a print head containing a number of metal pins which strike an inked ribbon placed between the print head and the paper.

“Non-Impact Printers” These printers create an image on the print medium without the use of force. They don’t touch the paper while creating an image. Non-impact printers are much quieter than impact printers as they don’t strike the paper.

“Dot Matrix Printer” Working :-The term dot matrix refers to the process of placing dots to form an image. Limitation:-This is the cheapest and the most noisy printer and has a low print quality.

“Advantages/Dis-advatages of Dot-Matrix” (1) In-expensive. (2) Low per page cost. (3) Energy efficient. Dis-advantages: (1) Noisy (2) Low resolution (3) Limited fonts flexibility (4) Poor quality graphics output.

“Ink-Jet Printer” It uses nozzles instead of pins It is a non-impact printer producing a high quality print. It uses nozzles instead of pins It spray ink from these nozzles

How Inkjet Printer works? (1) Print head having four ink cartridges moves . (2) Software instructs where to apply dots of ink, which color and what quantity to use. Color cartridge showing inkjet nozzles.

Advantages/ Dis-advantages (1) High resolution output. (2) Energy efficient. (3) Many options to select. Dis-advantages: (1) Expensive. (2) Special paper required for higher resolution output. (3) Time consuming in case of graphics printing.

“Laser Printer” In Laser printer we have cartridge containing toner. Laser printers used for image formation process. In Laser printer we have cartridge containing toner. A drum contained in elctrophotographic cartrige.