Multi-channel batch processing system, time-based system, and Real-Time System

Zookeeper1. Multi-Channel Batch Processing System
In a single batch processing system, there is only one job in the memory. It cannot make full use of all the resources in the system, resulting in poor system performance.
In a multi-channel batch processing system, all jobs submitted by the user are first stored in an external store and placed into a queue, which is called a "backup queue ". Then, the Job scheduler selects several jobs from the backup queue to transfer to the memory according to certain algorithms, so that they share the CPU and various resources in the system. Its advantages and disadvantages are:
(1) high resource utilization;
(2) high system throughput: system throughput refers to the total workload completed by the system per unit time. The main reasons for improving the system throughput can be summarized as follows: first, the CPU and other resources remain in the "busy" status; second, switch only when the job is completed or fails to run, low system overhead;
(3) long average turnaround time;
(4) No interaction capability.
2. Time-Sharing System
The time-based system and multi-channel batch processing system have different performance differences. It can provide a computer to multiple users for simultaneous use and improve the computer utilization. A time-sharing system means that multiple terminals with monitors and keyboards are connected to a host, and multiple users are allowed to use the computer through their own terminals in an interactive manner, share resources in the host. Its features are as follows:
(1) multiplexing: multiple online terminals can be connected to one host simultaneously, and the system serves each user based on the time-sharing principle.
(2) Independence: each user occupies a terminal and operates independently of each other without interfering with each other.
(3) Timeliness: users' requests can be responded in a short time.
(4) Interaction: users can conduct extensive man-machine conversations with the system through terminals.
3. Real-Time System
The so-called "real-time" means "timely", while a real-time system means that the system can respond to external event requests in a timely manner and process the event within the specified time, it also controls the coordinated operation of all real-time tasks. Its application requirements mainly involve real-time control and real-time information processing.