Evolution Of System Software
In the last 60 years, the computer has gone through different phases, we will discuss the evolution of the operating system as follows.
- Serial Processing
- Batch processing
- Real-time OS
- Distributed System
1. Serial Processing:-
Execution of process is Done serially (one after another).
Example:- Dos(Disk Operating-system)
2. Batch Programming:-
Batch means Group of Programs
Example:- Group of java programs, another group of c programs.
Advantages:- 1. Less time for Processing.
2. Switching(one program to another) time for less.
Disadvantage:- Cpu is idle.
More than one programs are loaded in memory at a time.
Here:- Context switch takes place(Context switch means Switching from one too another).
Example:- “C” Program and listening to music at the same time.
=> Switching takes place during I/O operation(Because During I/O operation CPU is Idle).
Advantage:- 1. The CPU utilization is more.
2. Overall time is less hence the system is faster.
4. Time Sharing:-
It is the special case of multiprogramming.
–> Program is given with a fixed time. this time is called “Time Quantum”
5. Real-time OS:-
Real-time refers to the exact time. It guarantees that the program must complete in time.
=> It is of two types.
- Hard RIOTS
Short time constraints. No Delay in the time allowed
Example:- ex-works (missile firing system, satellite launching system)
2. Soft RIOTS
Delay In time is allowed. Example:- Linux, window
6. Distributed System:-
It is a multiprocessor system. A group of computers is connected to share data. Each computer has its own memory.
LAN = college
MAN = city
WAN = World