-Easy-to-use programs designed to perform specific tasks.
-Set of programs designed to operate and control the computer.
It is a collection of programs that controls and manages the computer
Windows, Unix, MSDOS
Functions Of OS
It provide an interface between the hardware and the user.
It controls and co-ordinate the entire computer system.
It controls the allocation and use of various resource by various user and task.
It controls the various application programs.
Scheduling the jobs.
Process management, Memory management, Device management etc,.
TYPES OF OS
Single user/ single tasking OS
Single user/ multi tasking OS
Multi user/ multi tasking OS
Time sharing OS
Virtual storage OS
Real time system
Single user/Single tasking OS
One user works on the system
Performs one task at a time
Take up little space on disk
Run on inexpensive computers
Single user/Multitasking OS
User performs many tasks at once
Most common form of OS
Require expensive computers
Tend to be complex
Example: Windows XP
Multi user/Multitasking OS
Many users connect to one computer
Each user has a unique session
Maintenance can be easy
Requires a powerful computer
Example: UNIX, Linux, etc,.
Time sharing OS
It handles multiple jobs at a time.
It switches the CPU among various jobs that are running on the computer whenever there is a program break or a fixed time has expired.
Virtual storage OS
It uses the technique Demand paging. i.e. whenever the program size is larger than the main memory it splits the program into many pages.
Only the needed page is loaded to the main memory for execution.
Real-time operating system
It gets data from an on going event.
Respond quickly to user input.
Example: Reservation system
LOGICAL SYSTEM ARCHITECTURE
The physical components present in the computer is called Hardware.
Example: Keyboard, Monitor etc,.
It is a collection of programs which, performs some task.
It is collection of programs that controls and manage the computer.
Types:OS,Language processor etc,.
TYPES OF SOFTWARE APPLICATION SYSTEM SOFTWARE Example: Operating system, Device drivers, Language Processor, System utilities etc,. Example: Ms-Office, Reservation system, Payroll processing system Hospital management system etc,. GENERAL CUSTOMISED
It is a collection of programs that controls and manages all the components present in the computer
It is set of programs, which act as an interface between the computer and the device.
It is responsible for the proper functioning of the device.
COMPUTER D R I V E R S DEVICE 1 DEVICE 2 DEVICE n
It is a system s/w that translates the programs written in High level language to Machine language.
Machine language: 0’s and 1’s.
High level language: C, C++, Java etc,.
Example: Compiler, Interpreter, Assembler
It converts the programs written in high level language to machine language i.e. it translates the source code to object code.
HIGH LEVEL LANGUAGE C O M P I L E R MACHINE LANGUAGE
It converts the programs written in high level language to machine language.
It executes the source code in line-by-line manner.
I N T E R P R E T R E HIGH LEVEL LANGUAGE MACHINE LANGUAGE
It converts the programs written in Assembly language to machine language.
A S S E M B L E R ASSEMBLY LANGUAGE MACHINE LANGUAGE
These programs performs tasks related to the maintenance of computer
Example: Disk clean-up.
It is collection of programs that performs a specific task.
APPLICATION SOFTWARE (Cont)
Customised Application s/w
It is developed to meet the requirements of limited user.
General Application s/w
It is developed to meet the requirements of many user.
It is a software, which is permanently stored on the memory
It is software developed by some programmers and released for public use
The programming code is available so that the user can modify it.
S/W Terminologies (Cont)
It is a copyrighted software which is given away free by the owner.
It is developed by business organizations to earn profit