More components of a CPU that are vital to its operation are the registers, which are very small memory locations that are responsible for holding the data that is to be processed. The most important of these registers is known as the instruction pointer, which directs the CPU to the next memory location from where it is to receive information.
Amount of RAM installed will determine. Which software applications will run (efficiently)? How many software applications can be open simultaneously (multitasking ability)?
• Facilitate the storage and processing
of data under the direction of a
There are many parts that work
together to make a computer work.
Types of Devices
Digital versus Analog
- Most computers today are digital. Their circuits
have only two possible states, such as “Off” and
“On” or “0” and “1”.
- An analog device operates on continuously varying
data and has an infinite number of possible states.
Basic Hardware units of a computer
Central Processing Unit
• Memory (RAM)
• Hard Disk
• System Unit
• Power supply
•CD/ DVD Rom Drive
What is the system unit?
A boxlike case that houses the
computer’s main hardware components
• also called “The Chip”, a CPU, a processor, a
microprocessor or “brain” of the computer.
What are the components of the
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Control Unit- Coordinates and controls all
parts of the computer system
Manages four basic operations (machine cycle)
Fetch- Gets next program instruction from the
Decode- Figure out what the program is telling
the computer to do
Execute- Perform the requested action
Write-back (Store)- Write (store) the results to
a register or to memory
Control unit ALU
How a CPU works
Arithmetic-Logic Unit (ALU)
-Perform basic arithmetic or logic operations
-Add, Subtract, Multiply, Divide
-Compare two items to see which one is larger
• Stores the most frequently used instructions and
• The instruction pointer
- A term for a device that enables the computer to
retain (store) information.
- Holds instructions for processing data, processed
data, and raw data.
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HOW DOES RAM WORK?
-Large printed circuit board with thousands of
electrical circuits where most of the electronics
including the CPU are mounted
COMP1 AMaa’m Annalie
• Capacity is measured in
gigabytes (GB or billions
• Typically permanently
• Used to store operating
software, utilities and
It supplies DC power to the other components in a
• A circuit board that
permits a computer to
participate in a
• has a unique number;
this is used for
addressing. It is called
the MAC address.
• is an internal
card that facilitates
the input and
output of audio
signals to and from
CD/ DVD Rom Drive
• Optical storage device.
• Used more often now for backup storage
• Connects the
computer to the
monitor. It is a circuit
board attached to the
contains the memory
and other circuitry
necessary to send
information to the
monitor for display on
• Input is all information put into a computer.
Input can be supplied from a variety of sources:
– A person
– A storage device on computer
– Another computer
– A peripheral device
– Another piece of equipment
• Input devices gather and translate data into a
form the computer understands.
• Primary input device:
– Keyboard - Most common input device; used
to type in commands and data.
– Mouse or trackball enhances user’s ability to
input commands, manipulate text, images.
– Joystick useful in education as an adaptive or
assistive input device.
• Scanners are peripheral input devices which
allow users to import:
– Text , Graphics and Images
• Digital Cameras are peripheral input devices
that allow users to create pictures and/or movies
in a digital format.
• Microphone - Allows the user to record sounds as
input to their computer.
Those parts of the computer that provide results of
computation to the person using the computer.
• Monitors are the most commonly used output
- connected to a computer system via a port
integrated on the video adapter or graphics card.
• Printers- An output device that produces a hard
copy on paper.
• Speakers - Used to generate or reproduce voice,
music, and other sounds.