Thursday, May 1, 2008

Peripheral Devices, INPUT OUTPUT

OUTPUT DEVICES

SPEAKER
HEADPHONES
PRINTER

MONITOR


INPUT DEVICES




WEBCAM

KEYBOARD MOUSE
COMPUTER MICROPHONE
SCANNER

Sunday, March 30, 2008

Different Types of Software

OPERATING SYSTEM
Operating system is a complex program that controls the entire operation of the computer.

USER INTERFACE
This is the means of communication between the system and the user.

TRANSLATOR
Translators converts/translates programming languages into computer language that would make sense to the computer so that commands coul take place.

UTILITIES
These are designed to carry out certain routine functions such as file management,editing files,re-organising disk space making back ups and so on.

PROGRAMMING LANGUAGES
Programming languages are used to set instructions/commands so that the computer will bring about an operation.

GENERIC/COMMON APPLICATION SOFTWARE.
These softwares helps the user to preform a task that the user wishes to preform, different generic application softwares have different capabilities.
Different types of genereal application softwares are: microsoft words,excel,spreadsheet
.

PURPOSES OF HARDWARE

INPUT DEVICES

PURPOSES:
it is used to provide data and controls signals to an information processing system.

Typical examples of input devices:
Keyboard,Mouse,Microphone

STORAGE DEVICES

PURPOSES:
Storage devices are used so that data would not be lost, and the data saved could be used at later stages when required.
Storage devices are also used so that data can be transferred from one computer to another, for example you can store your unfinished work that has been done on school computer into storage device so that it could be retrieved on your pc at home so that work can be completed at home.

Examples of storage devices:
ROM,RAM,USB Pendrive,CD-RW

OUTPUT DEVICES

PURPOSES:
These devices make information accessible after being processed, output can be of different types such as visual output,audible output, hard copy of printed work.

Examples of output device:
Monitor,Speakers

COMPUTER TERMS

HARDWARE

Hardware devices also referred to as peripherals(devices external to CPU andmain memory) make up a computer system.
Hardware typically supplied with computer system includes the computer itself(containing one or more hard disk drives), a screen, a keyboard, a mouse and one or more additional disk and CD drives.

These devices can be split into 4 types:

INPUT DEVICES
Which are used to input data into computer
CENTRAL PROCESSING UNIT
This is where all instructions are carried out, it is the brain of the whole system.
BACKING STORE
This is where data is stored when power is switched off.
OUTPUT DEVICES
These devices provides output.

SOFTWARE

Softwares are designed to carry out user-related tasks.

There are 5 categories of software:

GENERAL PURPOSE APPLICATION SOFTWARE
These are the common software pakages that are found on most computers, for example microsoft words,spreadsheet.
SPECIAL PURPOSE APPLICATION SOFTWARE
Softwares that are built for a particular requirement, a traffic control department
would need to employ an expert to write a specialised software to fit its requirement.
PROGRAMMING LANGUAGES,COMPILERS&INTERPRETERS
Programming languages are used to set instructions or commands to form operations.
OPERATING SYSTEMS
This is a complex program that controls the entire operation of the computer
UTILITY PROGRAMS
These preform task such as repairing damaged files.

INPUT DEVICES

These devices are needed to input raw data into a computer system.

Examples of input devices:
keyboards,mouse,scanners,microphone.

STORAGE DEVICES

Storage devices stores data so it can be utilised when required (can be used again next time when needed).

Examples are:
ROM(read only memory),RAM(random access memory),hardisks,floppy disks,CD-ROMS/compact disks,CD-R(CD recordable),CD-RW(CD re-writeable),DVD(digital versatile disks)

OUTPUT DEVICES

After data processing information if formed and in order to make these information accessible, output devices are needed to provide an output.
Out put can be of different types such as visual output,audible output, hard copy of printed work.

Examples are:
Monitor,printers,speakers,control devices such as lights and buzzers.

Wednesday, March 12, 2008

OPERATING SYSTEM

PURPOSES/FUNCTIONS OF OPERATING SYSTEM:
  1. -It allocates a time slot with the processor
  2. -It allocates memory for storing programs and data so when data is needed it can be found easily.
  3. -It ensures that jobs with different priorities are dealt with in the correct order
  4. -The system takes care of data storage in the computer systems memory.
  5. -It has routines for handling input and output operations
  6. -It accpets commands and data from the user via inout devices.
  7. -The system looks after transfer of data between the backing store and memory
  8. -It also manages system security

METHODS OF OPERATION

SINGLE PROGRAM MODE:

Runs with just one program at a time, with one user

MULTI-TASKING MODE/MULTI-PROGRAM MODE:

runs with two or more programs at a time with one user

MULTI-USER MODE:

Several users are able to use the same system together

MULTI-PROCESSOR MODE:

In larger systems,there will be more then one processor.The operating system allows the different processor to operate togeter and utilise the same memory.

UTILITY PROGRAMS

VIRUS CHECKERS:-
  1. These are computer programs which identify, neutralize or eliminate malicious data.

  2. virus checker detects maliciuos data (viruses) by scanning through files

  3. Virus checkers Identifys suspicious behavior from any computer program which might indicate infection. Such analysis may include data captures, port monitoring and other methods.

  4. Nowadays virus checkers are also installed to mobile phones.

  5. Anti virus can take one of the following actions: attempt to repair the file by removing the virus itself from the file,quarantine the file or delete the infected file.

EXAMPLES OF ANTI-VIRUS:

kasperskys, AVG , McAfee

SOFTWARES

GENERAL PURPOSE APPLICATION SOFTWARE:
General purpose packages are very popular because their documentation(manuals,tutorials,etc) is usually excellent,programs are well tested and they are inexpensive.

EXAMPLE:
Microsoft words and spreadsheet



SPECIAL PURPOSE APPLICATION SOFTWARE:
These softwares are built for a particular requirement.

EXAMPLE:
The traffic control department would need this software to operate trafficlights, a big database for a bank.

PROGRAMMING LANGUAGES:
Programmers use different types of programming languages which are used as set of instructions or commands to form a program.

EXAMPLE:
visual basic ,java





OPERATING SYSTEM:
Operating system is a complex program that controls entire operation of the computer.
The means of communication between user,system hardware and software is called the user interface. Via the user interface, the user indicates what he/she wishes to do, and the operating system provides the routines that are needed to allow the hardware to interact with application software.

EXAMPLE:
linux,windows vista


UTILITY PROGRAMS:

Utility programs perform common tasks such as formatting disks,copying and deleting files or repairing damaged files.

EXAMPLE:
Anti virus, disk defrag