these slides describes the basic components of a System Unit

1. Components of System Unit
Presented by:
Maria Yousaf
15331556-094
BS IT (4th Sem)
Instructor:
Ahsan Ali

2. System unit
 It contains electronic components of the computers used to process data.
 it is where all your computer peripherals are attached. It is composed of 6 basic
components of system unit, namely; motherboard, processor, ram, hard drive,
video card and power supply. It is often called as CPU but it is not, the CPU (central
processing unit). is the processor itself.

3. Components of System Unit
 Processor
 Memory
 Adapter cards
 Ports
 Hard Drive
 Power supply

5. Motherboard:
 It is the core of the system, it
really is the PC. Everything else
is connected to it, and it
controls everything in the
system.
 The motherboard or system
board is the main circuit board
of the system unit.

6. (Cont.)
 Connects all components.
 Allows communication
between devices
 Contains adapter cards,
processor chips, and
memory chips

7. Processor
 it is often thought of as the engine of the computer. It is also called the CPU.
Microprocessor is a solid-state central processing unit much like a computer on a
chip. An integrated circuit that accepts coded instructions for execution. For me,
processor is the brain of the system. There are two types of processor; with pins
and the pin-less .

8. Memory
 Electronic components that store instructions, data, and results
 It is the system memory often called as RAM (random access memory). This is the
primary memory, which holds all the programs and data the processor is using at a
given time
 All memory accessible at any instant (randomly) by a microprocessor. The latest
type of RAM is the DDR3.

9. (Cont.)
 RAM Task
Explore, SRAM, DRAM,
SIMM, DIMM and RIMM.
 Virtual Memory
Small portion of hard Disk
acts as RAM.
 Cache
It helps to increase speed of computer.
It stores frequently used data and instructions
The more RAM a
computer has, the
faster it responds
Also called
main memory
or primary
storage
Most RAM is
volatile, it is lost
when computer’s
power is
turned off
Memory chips that can be
read from and written
to by processor

10. (Cont.)
 ROM
Memory chips that store permanent data
and instructions.
Nonvolatile memory, it is not lost when
computer’s power is turned off.
 Registers
A register is a single storage location within the CPU
Unlike memory, which is “outside” the CPU
 Flash Memory
Nonvolatile memory that can be erased electronically and reprogrammed.

11. Hard Drive
 is the primary archival storage memory for the system
 It is where we saved our files and data including our operating system, antivirus
and other applications.
 There are two types of Hard drive, we have PATA (Parallel Attachment Packet
Interface) then SATA (Serial Attachment Packet Interface).

12. Adapter Cards & Expansion slots
 Enhances system unit or provides connections to external devices called
peripherals
 Also called an expansion card
 Flash Memory Cards, PC Cards

13. Ports
 Port connects external devices
to system unit.
 Serial Port
Transmits one bit of data at a time.
Connects slow-speed devices, such as
mouse, keyboard, modem.
 Parallel Port
Connects devices that can transfer more
than one bit at a time, such as a printer.

14. Serial port VS Parallel port

15. Power Supply
 It is the one that feeds electrical power (voltages and currents) to every single part
in the PC.
 The latest power supply support both SATA and PATA connectors.