chasis / system cabinet a plastic enclosure that contains most of the components of a computer...

System unit components

Chasis / System cabinet A plastic enclosure that contains most

of the components of a computer (usually excluding the display, keyboard and mouse)

System Unit:

System Unit

Tower top All in oneDesktop

Information Technology Chapter 03

The central printed circuit board (PCB) in many modern computers that holds many of the crucial components of the system, providing connectors for other peripherals.

Mainboard / System board Communication medium for entire computer

Motherboard:


Motherboard- Inside view:


Processor/Brain of computer A complete computation engine that is

fabricated on a single chip The portion of a computer system that

carries out the instructions of a computer program, to perform the basic arithmetical, logical, and input/output operations of the system.

Multi core processor: single chipcontaining two or more processors

Central Processing System (CPU):


Dual core processors: Single chip containing two processors

Quad core processors: Single chip containing four separate processors

Multi core processors


1. Arithmetic & Logic unit◦ Arithmetic operations and logical comparisons

2. Control unit◦ Controls and coordinates all activities of a

computer system by issuing necessary commands

1. Fetches instruction from main memory2. Interprets instruction to find what operation to

perform3. Controls execution of instruction

Main units of CPU:


1. Fetch -get an instruction from Main Memory

2. Decode -translate it into computer commands

3. Execute -actually process the command4. Store -write the result to Main Memory

Machine cycle/Instruction cycle:

CPU /


Set of all instructions that a cpu can perform1. Arithmetic instructions2. Logical instructions3. Data transfer instructions4. Control transfer instructions

Used to change the sequence of instructions of a program

Instruction set:


Electronic component that generates electric signals at fast speed

It controls all the functions of computer using clock ticks

The power of a CPU is determined by the speed with which it processes data. The more instructions in a second, faster will be the CPU.

Processor speed is measured in MHz (million instruction/sec) and GHz (billion instruction/sec)

System Clock:


Processor register is a small amount of storage available as part of a CPU

Used to store information being processed Register size How much information it can

store (one/ two/ four/ eight bytes) CU manages registers for:

◦ Input instruction or data◦ Store instruction or data◦ Transfer instruction or data◦ Perform ALU operations at high speed

Registers:



A component designed to lower the temperature of an electronic device by dissipating heat into the surrounding air.

All modern CPUs require a heat sink. Some also require a fan.

A heat sink without a fan is called a passive heat sink; a heat sink with a fan is called an active heat sink.

Heat sinks are generally made of an aluminum alloy and often have fins.

Heat sinks/ Heat pipes:


Data and instructions to be executed are stored in memory

It stores:◦ Operating system and other system software to

control the use of computer system◦ Application programs to perform specific tasks◦ Data to be processed by application programs

Memory:


Volatile Memory: RAM Non Volatile Memory : ROM

Types of Memory


Generates output images to a display A special circuit board that controls what is

shown on a computer monitor and calculates 3D images and graphics.

Amount of memory located on card must be enough to support the desired numbers of colours and resolution

Its capacity is 32 MB today

Types of expension cards: Video Card


Enhances the sound generating capabilities of a computer

Takes input from microphone converts it into machine language

Sends audio output to speakers

Sound Card


Network interface controller / network adapter/ LAN adapter

This provides a base for a full network protocol stack, allowing communication among small groups of computers on the same LAN and large-scale network communications through routable protocols, connects a computer to a computer network.

NIC- Network Interface Card


A kind of television tuner that allows television signals to be received by a computer

TV tuner Card


A modem (modulator-demodulator) is a device that modulates an analog carrier signal to encode digital information, and also demodulates such a carrier signal to decode the transmitted information.

The goal is to produce a signal that can be transmitted easily and decoded to reproduce the original digital data

Modem Card


Used to add memory, disk drives, sound, fax, modem and other capabilities to a mobile computer like laptop

Pc Cards


In computer hardware, a port serves as an interface between the computer and other computers or peripheral devices.

A port is a specialized outlet on a piece of equipment to which a plug or cable connects.

Ports:


Ports has different connectors. The various connectors on the computer

allow it to communicate with the many different devices and peripherals attached.

Connectors are called input/output ports (i/o ports) or communication ports.

Connectors


A standard-sized area for adding hardware to a computer. Most drive bays are fixed to the inside of a case, but some can be removed.

A simple way to add, remove, and share hardware devices

External/ Exposed drive bay:◦ Used to access the drive from outside the system

Internal / Hidden drive bay: ◦ It is hidden inside the system unit

e.g for hard disk

Bays / Drive bay/ Device Bay:


Power supply converts the alternating current (AC) line from our home to the direct current (DC) needed by the internal components of personal computer

The typical voltages supplied are: 3.3 volts 5 volts 12 volts

Power Supply / switching power supplies :

chasis / system cabinet a plastic enclosure that contains most of the components of a computer...

Documents

computer system

data transfer instructions

logical instructions

arithmetic instructions

data store instruction

computer program

control transfer instructions

computer commands