Description of points:
1. Manual operation
User exclusive whole machine, CPU waits for manual operation; manual severely reduce the utilization of computer resources, the so-called human contradictions.
2. off-line input / output (I / O) mode
Introduction of the magnetic tape, the program data to be input on the tape, as needed programs and data, and then transferred to a high speed from the magnetic tape memory.
Input and output: line input / output,
Advantages: reducing the idle time of the CPU; improved I / O speed.
3. The single-batch system
Pipelined work,
Single-batch system is to solve the contradiction between the display unit and the CPU and I / O devices during a speed mismatch contradictory formed;
Batch system is designed to improve the utilization of system resources and system throughput.
Disadvantages: The system can not make full use of resources, resulting in a waste of memory.
4. Multi-batch system
Concept: when resource utilization and improve system throughput, A, B, C program execution, there are I / O CPU temporarily stops the operation of the line, A in the I / O operation, B performed, B in the I / O operation when, C execution. That the multi-channel run alternately.
Advantages and disadvantages: high resource utilization; large system throughput. The average turnaround time is long; no interaction.
The time-sharing system
Refers to a time-sharing system, on a host connected to a plurality of terminal with a display and a keyboard, and the system thus composed, the system allows multiple users through their own terminal, using a computer interactively, shared hosting resource of.
Features: multiple, independence, timeliness, interactivity.
The main objective of the time-sharing system : in response to a timely user, i.e. the user will not wait for the processing time of each command is too long.
Multi-user time-sharing system is a kind of operating system of today's computer operating system is the most commonly used.
6. Real-Time Systems
Coordinated operation of the system can promptly respond to requests external events, complete the processing of the incident within the specified time, and control all real-time tasks.
Wherein: multiplexity (periodicity information collection, a plurality of actuators or control objects), independence, timeliness, interactivity, reliability (multi-level fault tolerance measure).