INPUT
Input is the collection of raw data/facts; hence
translating into image, word, sound and action that people understand into a
form that the System Unit can understand and process. (e.g. using a form on the
website to collect visitor’s opinion, collecting facts about a research
project, typing and processing using the computer keyboard or mouse.
Input devices are those responsible for the insertion
of data into the computer that is instructing the computer. Data is referred to
as the “raw material” of information.
Examples of input devices include; keyboard, mouse,
joystick, Webcam, etc.
PROCESSING
Processing is the means by which
computer programs and instructions are being executed.
Processing
devices are those devices directly responsible for the transformation of data
into information. The processor is the main component in the System unit
capable of interpreting computer program instruction and process data. Another
vital component for processing is the RAM; It receives and temporary stores
data and program instruction from the CPU.
OUTPUT
Out
put refers to processed data or information. Output is the process of
transmitting the processing information into a form that makes sense to human. Output
devices are those use to display data that has been process either in hardware
or software form to make sense to an individual or group of persons.
Information is referred to as the result of processed data which makes sense in
life.
Example of output devices includes; printer, monitor,
etc.
An
information processing system is a system which takes information from one form
(be it electrical, mechanical or biological) and process (transform) it to
another form by an algorithmic process. An example of such system is the
computer.
The
diagram below clearly explains the input, processing and output devices and how
they function.
COMPUTER STORAGE
Computer
storage refers to the action of a computer which permits it to store data and information
while computer storage devices refer to those devices responsible for the
storing of these data and information. It is a mechanical apparatus that has
the ability to store data and also to retrieve this data. Those devices that
stores data for a long time are said to be permanent storage devices while
those that stores data or information for a short time are referred to as
temporal storage devices.
Computer
storage devices are divided into two;
PRIMARY STORAGE DEVICES
This refers to those storage devices which are
incorporated with the mother board of the system.(the system unit is the box –
like structure which contain the processor, RAM, mother board and many other
hardware components). They have small storage capacity.
The constitute the RAM and the ROM.
i)
RAM (Random Access Memory)
It stores
information temporary for the purpose of processing and loses the information
in case of power failure. Hence it is term volatile memory.
As the name implies, information or data stored on
this device will be lost in case of power failure. It stores data temporary in
order to feed the processor with data to be processed and also stores
information temporary after processing before onward storage to a secondary
storage (HDD).
This memory can
permit information to be read from it and to be written to it.
ii)
ROM
(read only memory)
This memory
stores information permanently. It contains the manuacturer’s information.
From the name read only, information on this memory can only be read, it cannot
be added, replace or deleted. In clear term read only means the information cannot
be edited. This memory is used to store the basic set of information called
BIOS (Basic Input, Output System). It contains information for starting up the
computer. The information are said to be hard wired on the mother board of the
computer.
Software stored
on the ROM are often called firmware because is more like hardware than
software.
SECONDARY STORAGE DEVICES
These are storage devices which have the ability to store data for a long
period of time. They can only store data or information but they cannot carry
out any control, logical or arithmetic function. Their example includes; Hard
disk, Flash disk, Memory card, etc.
These devices are externally attached to the computer
system unit or connected to the computer using a bus cable. The most common
storage devices are made up of Magnetic storage having large storage capacity
and fast access of data ( for hard disk, diskette and tape storage), and
Optical storage ( for CD-ROM, WOROM AND DVD). Information on this devices are
being stored to be used by a computer user when need be. They will retain their
information incase of power failure. They generally have high storage capacity
and information or data on it may be edited.
SOME DEFINITIONS IN DATA STORAGE
Data storage: Movement of data from one storage
medium to computer memory.
Data compression: The process of condensing data so
that it requires fewer bytes for storage.
Data transfer rate: The speed at which data can be
transformed between the storage medium and computer memory. Transfer rates are
expressed in bytes per second (bps).
Data transport: Data travels from one location to another
within the computer on an electrical pathway or circuit called a data bus. The
data bus is a series of circuits that connects the various electrical
components on the motherboard. The bus contains data lines and address lines. Data
lines carry the signal that represent data while address line carries signal
that specify where the computer can find this data that it is supposed to
process
MICROPROCESSOR AND MEMORY
The microprocessor is also referred to as the CPU (or
at time simply the processor). It is a silicon chip (integrated circuit)
designs to control data.
It main function
is to execute instruction to process data.
This information
and data are retrieved from the RAM so that it can be displayed and stored.
The CPU has
three components (The Control Unit, ALU and the Memory). The two main
components are the Control Unit and the ALU.
4.1 THE ALU:
The ALU does all
the arithmetic and logical operations needed for the computer to solve a
particular problem.
The ALU uses
register to hold data that are being processed.
The result of an
arithmetic or logical operation is stored on the accumulator.
From the
accumulator the data can be send to the RAM or use for further processing.
THE CONTROL UNIT:
It main function
is to execute the instruction which have been stored in the memory
It reads and
interprets programme instruction (the process of interpreting is term
decoding).
The Control Unit
directs the movement of data from the RAM to the ALU
This movement is
made possible by the use of data buses (buses refers to the belt-like cables in
the System Unit use to transmit data and information).
In conclusion;
the function of the Control Unit is to ; Fetch the instruction, Decode the
programme instruction, Execute the instruction and to write the result from the
ALU to the memory location or to the register or perhaps an output device.
PROGRAMME COUNTER (SEQUENCE CONTROL REGISTER):
This is a set of
memory call register that instruction can be read from and written to, more
faster than the main memory ( RAM ).
Registers are
use for most frequently use data to avoid accessing the RAM each time which is
often slow compared to the ALU and the Control Unit.
No comments:
Post a Comment