Batch processing operating system

batch processing operating system

Excerpt from the development and classification of the operating system

In order to solve the contradiction between human-machine contradiction and the speed mismatch between CPU and I/O device, Batch processing system appeared. According to the development process, it is divided into single-channel batch processing system, multi-channel batch processing system (after the advent of multi-channel program design Technology).

1) Single-channel batch processing system

The system handles the job in batches, but always keeps a job in memory. The system is formed in the contradiction between human-machine contradiction and the rate mismatch between CPU and I/O device. The main features of the single-channel batch processing system are as follows: Automatic. In a smooth situation, a batch of jobs on the tape can be automatically run sequentially, without manual intervention. Sequential. Each job on the tape is sequentially entered into memory, the order in which the jobs are completed and the order in which they enter the memory, which should normally be the same, that is, the job that is first transferred into memory is completed first. Single-channel sex. In memory, only one program runs, that is, the watchdog every time from tape to only one program into the memory run, when the program completed or abnormal situation, only to swap in its successor program into memory run.

The problem at this point is that the high-speed CPU waits for a slow I/O completion state every time that a single job is stored in the host memory, whenever it is running (note that this is "runtime", not "after") making an input/output request. In order to further improve the utilization of resources and the throughput of the system, multi-channel program technology is introduced.

2) multi-channel batch processing system

Multi-Channel program design technology allows multiple programs to enter memory and run simultaneously. That is, putting multiple programs into memory and allowing them to run alternately on the CPU, sharing the various hardware and software resources in the system. When a program pauses to run due to an I/O request, the CPU immediately goes to run another program. It does not use some mechanism to improve the bottleneck problem of a technology, but to let the various components of the system as far as possible to "busy", spend little time to switch tasks, to achieve the system between the parts of the parallel work, so that its overall efficiency in the unit time doubled.

Multi-Channel Program design features: Multi-channel: computer memory in the same time to store multi-channel independent program. Macro-parallel: At the same time into the system of multi-channel programs are in operation, that is, they have started their own operation, but have not finished running.
Micro-Serial: In-memory multi-channel programs take advantage of CPU rotation, alternating execution.

The implementation of multi-channel program design technology needs to solve the following problems: How to allocate processor. Memory allocation problem for multi-channel programs. How I/O devices are allocated. How to organize and store a large number of programs and data so that users can use and ensure their security and consistency.

Multi-channel batch processing system is formed in batch processing system by using multi-channel program design Technology. The system sends the jobs submitted by the user to the computer memory in batches, and then the job scheduler automatically chooses the job to run.

The advantage is that the resource utilization is high, the multi-channel program shares the computer resources, so that all kinds of resources are fully utilized; The system throughput is large and the CPU and other resources remain "busy". The disadvantage is that the user responds for a longer period of time. Does not provide the human-computer interaction ability, the user can not understand own program operation condition, also cannot control the computer.