- The peripherals (or peripheral components) are
auxiliary devices to help the
computer system
interact with its human users.
- Function of
input devices:
- Enables human users
to enter data
into the computer (= machine)
Important:
- The data will be stored inside the computer in such a way that the computer can use it effectively.
- There many different forms of inputs: text (keyboard), pointing (mouse), graphics (scanner), stored information (disk files), etc.
- Enables human users
to enter data
into the computer (= machine)
- Function of
output devices:
- Enables the computer to
show data stored inside the computer
to a human user
in a "humanly" way
- There are many different forms of outputs: text (terminal), audio (speakers), visual (graphic displays), ..., etc.
- Enables the computer to
show data stored inside the computer
to a human user
in a "humanly" way
- What the computer system can
do with peripheral devices:
- The CPU can
instruct an
input device
to read user input and
store
a representation of the input
in the memory:
Example:
- When the user enters
"A" on the
key board, the
key board will
send 01000001 to
the computer system ---
01000001 is
the representation
of the letter "A"
We will learn about representing the letters in an alphabet using ASCII codes later
The user input must be converted into a suitable format for the computer to process
The representation of the user input will subsequently be processed by the CPU
- When the user enters
"A" on the
key board, the
key board will
send 01000001 to
the computer system ---
01000001 is
the representation
of the letter "A"
- The CPU can
instruct an
output device
to display some
data in memory
to an output device
so the user can
see/hear it:
Example:
- When the computer sends 01000001 (= the representation of the letter "A") to the terminal, the terminal will paint the symbol "A" on its screen
So the (internal) representation must also be converted into a suitable format for the user to see/read
The output devices are specially design to perform these "conversion" so humans can "see"/"interpret" the internal representations used by the computer
- The CPU can
instruct an
input device
to read user input and
store
a representation of the input
in the memory: