The physical components of a computer system.
Everything you can see and touch.
A processor is a chip that responds to and processes the
basic instructions that drive a computer.
The processor in a personal computer is often called a
Pentium 4 Processor
The processor is like the ‘brain’ of the computer system.
(BUT not a real brain as a computer cant think or act for
A set of
s in a
Computers can carry out instructions very quickly
because the processor can process billions of
instructions every second.
The processor can’t store a whole program at the one
time. A computer must have memory to store programs
and data its not using at any particular time.
types of memory chips used for a different
purpose in a computer system.
RAM and ROM
Random Access Memory (RAM)
Is the place in a computer where the operating system,
application programs, and data in current use are kept so
that they can be quickly reached by the computer's
RAM is much faster to read from and write to than the other
kinds of storage in a computer.
The data in RAM stays there only as long as your computer
is running. When you turn the computer off, RAM loses its
Read Only Memory (ROM)
ROM can be used to store programs and data permanently.
Data cannot be easily written to ROM, depending on the
technology used in the ROM, writing may require special
hardware, or may be impossible.
A computer's BIOS may be stored in ROM
RAM V’s ROM
RAM holds programs and
Program and data are lost
when the computer is
RAM holds programs that
are currently running on
ROM holds programs and
The contents of ROM are
not lost when the computer
is switched off.
ROM hold programs
has been programmed
onto the chip at the factory
and cannot be changed
Change in Technology
The price of memory chips is continuing to go down.
The memory size of computers (ROM and RAM) has gone
Chips work faster and can handle more data in a single
Complete computers can be produced on a single chip.
Computers are now tiny, for example palmtop computers.
Types of Computers
Personal Digital Assistants (PDA)
Palmtops are tightly integrated computers that often use
flash memory instead of a hard drive for storage.
These computers usually do not have keyboards but rely
on touchscreen technology for user input with a stylus.
Palmtops are typically smaller than a paperback novel,
very lightweight with a reasonable battery life.
Most types use a LCD screen as the input device.
This is a compact type of computer that can run on
batteries that is entirely
. Normally has a hard
disk, floppy disk and a CD
Uses an LCD/TFT screen as an output device. LCD use
Laptop computers typically use a track pad or a raised
button to control the pointer on the screen.
A type of notebook computer that has an LCD screen on
which the user can write using a special
purpose pen, or
The handwriting is digitized and can be converted to
standard text through handwriting recognition, or it can
remain as handwritten text.
A keyboard can be attached for data entry.
Most desktops come with the following:
Monitor (LCD, TFT at an extra cost)
Full size keyboard (function keys, numeric keypad)
Mouse with a scroll wheel (wireless at an extra cost)
Floppy Disk Drive (several manufactures do not include
ROM Drive (may have a CD rewriter)
ROM Drive (may have a DVD rewriter)
Peripheral devices may come with your computer such as:
A computer that delivers information and software to other
computers (clients) linked by a network.
A network interface card is required in order to connect to
Different types of servers:
File Server (storage of users programs and data)
Printer Server (queuing facility)
ROM server (access data from one or more CD
ROMS held within it)
Very large computer system which can process very large
amount of data at a high speed.
It may be connected to hundreds of user
Vast amount of RAM and many extra peripherals such as
tape and disk drives.
The ‘dumb’ terminal has no processor and no local storage
devices. All that is required is a screen and a keyboard.
More than one person using a
mainframe computer system at
the same time
More than one program running
on a computer system at the
Used for intensive mathematical calculations such as:
Weather and climate forecasting
Digital Animation in motion pictures.