Sunday, July 31, 2016

5 functional units of a computer



Input Unit: This is the unit used for sending or transferring data, commands into the
Computer for processing, thereby helping users to communicate with the computer system, it acts as an interface between the user and the system.
Examples of input unit are:
i.                    keyboard,
ii.                  joysticks,
iii.                scanners,
iv.                light pen,
v.                  electronic tablet
vi.                Digitizer. Etc.

Processing Unit: This is the responsible for processing all the various operations that goes on in the system unit. It is referred to as the brain of the computer system, without it the computer will be valueless.
Example of processing unit is the central processing unit (CPU). 
The processing unit can be divided into three sections:
i     Control Unit
ii    Arithmetic and logical unit (ALU)
iii   Memory Unit.

 The Control Unit: This unit coordinates all the various operations of the input and output units in the system unit precisely the Central Processing Unit (CPU).

Functions of the control unit
i.                    It directs the sequence of operations,
ii.                  It interprets the instructions, of a program, in storage unit and produces signals the command circuits to execute the instructions.
iii.                It directs the flow of all activities in the computer system.

The arithmetic and logical unit:   This unit is responsible for performing all the various Arithmetic operation of addition, subtraction, multiplication, division and relational operations Such as not equal to (¹) greater than (>) less than (< ) greater than or equal to (≥) and logical operation. Etc.

The memory unit:  This unit otherwise known to be the main or primary memory (storage). It stores information (i.e. instruction data intermediate and final result of processing) that arrives via the input unit so that this information is made available to the appropriate Quarters for further processing after which they can be presented to the user via the Output unit.
  
The memory unit divided into two:
i.                    Random Access Memory (RAM)
ii.                  Read Only Memory(ROM)
Other versions of ROM are:
·         PROM(Programmable Read Only Memory)
·         EPROM.(Erasable Programmable Read Only Memory)

Output Unit: This unit displays the result of the processed data for the user
Examples of output unit are:
i.                     monitor (visual display unit-VDU)
ii.                   Printers
iii.                Card Reader
iv.                Magnetic Tape
v.                  Microfilm etc.

functional unit of computer



Basic Functional units of a Computer
The basic computer system consists of five units:
i     Input Unit
ii    Control Unit
iii   Arithmetic Unit(contained in the CPU, or central processing unit),
iv   Memory Unit
v    Output Unit



Input Unit: This is the unit used for sending or transferring data, commands into the
Computer for processing, thereby helping users to communicate with the computer system, it acts as an interface between the user and the system.
Examples of input unit are:
i.                    keyboard,
ii.                  joysticks,
iii.                scanners,
iv.                light pen,
v.                  electronic tablet
vi.                Digitizer. Etc.

Processing Unit: This is the responsible for processing all the various operations that goes on in the system unit. It is referred to as the brain of the computer system, without it the computer will be valueless.
Example of processing unit is the central processing unit (CPU). 
The processing unit can be divided into three sections:
i     Control Unit
ii    Arithmetic and logical unit (ALU)
iii   Memory Unit.

 The Control Unit: This unit coordinates all the various operations of the input and output units in the system unit precisely the Central Processing Unit (CPU).

Functions of the control unit
i.                    It directs the sequence of operations,
ii.                  It interprets the instructions, of a program, in storage unit and produces signals the command circuits to execute the instructions.
iii.                It directs the flow of all activities in the computer system.

The arithmetic and logical unit:   This unit is responsible for performing all the various Arithmetic operation of addition, subtraction, multiplication, division and relational operations Such as not equal to (¹) greater than (>) less than (< ) greater than or equal to (≥) and logical operation. Etc.

The memory unit:  This unit otherwise known to be the main or primary memory (storage). It stores information (i.e. instruction data intermediate and final result of processing) that arrives via the input unit so that this information is made available to the appropriate Quarters for further processing after which they can be presented to the user via the Output unit.
  
The memory unit divided into two:
i.                    Random Access Memory (RAM)
ii.                  Read Only Memory(ROM)
Other versions of ROM are:
·         PROM(Programmable Read Only Memory)
·         EPROM.(Erasable Programmable Read Only Memory)

Output Unit: This unit displays the result of the processed data for the user
Examples of output unit are:
i.                     monitor (visual display unit-VDU)
ii.                   Printers
iii.                Card Reader
iv.                Magnetic Tape
v.                  Microfilm etc.

what is the importance of an operating system

Operating system: it is a collection of software consisting of control routine that co-ordinate hardware activity. It is a term used to describe a collection of program modules that supervises the operation and use of all system resources to ensure their efficient and judicious management. It is a unit of program which takes over the operation of the computer to the extent of being able to allow a number of .program to be run on the computer with little or no human intervention.

Importance of operating system

1.      It moderates the relationship between the computer and its peripherals
2.      It helps in the management of files,- copying, deleting, moving of files from one storage location to the other.
3.      It encourages the memory for its efficient usage and thus adding the speed of the computer.
4.      It manages the activities of the processor in terms of job execution according to the priority of arrival ,of jobs
5.      It informs the user of nay hardware or software error
6.      It makes communication between the computer and the user or the operator possible.

Types of operating system
i.                    Single user operating system
ii.                  Multiple user operating system

Examples of Application Software are:
·         Word Processor e.g. Microsoft word, word perfect, Word star etc
·         Graphical/ desktop packages e.g. Microsoft publisher, paintbrush, Corel draw, Ms Power point, PageMaker etc.
·         Database packages e.g. Dbase iii &iv etc
·         Spread sheet packages e.g. Ms Excel,  etc

types of micro computer



Types of Micro Computers

Microcomputers can be further divided into different types based on the size of their central processing unit (CPU) and other major and minor components. They are;-
(1)      Notebook Micro Computers; - these micro computers are having their sizes just like the size of exercise note books. As a result, they are handy.
(2)      Laptop Microcomputers; - these are the microcomputers that can be conveniently operated on the lap. They are bigger in size and slightly heavier than the notebooks. They can perform virtually all the function of the desktop microcomputers, yet very portable like the briefcase size. They can perform complex task anywhere, anytime with ease. They are expensive compare to other microcomputers with larger sizes; this is as a result of high technology with reduction in size.
(3)      Desktop Microcomputers: these computers can be placed on flat smooth tables (desk) for convenience and comfort ability when in use. They are bigger than notebooks and laptops. They can also perform various complex operations. Desktop microcomputers are subdivided into their sub-devices/ parts eg. The keyboard, monitor, system unit are all separated from one another having cables used for their connection before use unlike notebooks and laptop where all are permanently joined (connected) together when manufacture.
(4)      Minitower Microcomputers:  these are recent modification on the system unit, whereby the system unit is made to stand erect on its own and placed beside the monitor unlike desktop which lies flat on tables and monitors placed on it. They also have their parts separately having cables for connection.    
(5)      Full Tower microcomputer: These computers are closely related to the mini Tower, except that they are a bit higher and wider in physical size than the Mini Tower. All other things are the same as in Mini Tower Microcomputers.