Apps exist from the first generation of computers and continue over time. In this chapter, we will discuss some of the most important types of applications.

Batch work process

Batch app users are not directly connected to the computer. Each user prepares their work on an offline device such as punch cards and sends it to a computer operator. To speed up processing, tasks with similar needs are grouped together and conducted as a team. System planners leave their programs with the operator and the operator then sorts the programs with the same needs into clusters.

Batch Systems Problems  are as follows:

  • Lack of communication between user and employee.
  • The CPU often does not work, because the speed of the machine's I / O devices is slower than the CPU.
  • It’s hard to give the essentials what you want.

Time sharing programs

Time sharing is a method that allows many people, from different terminals, to use a particular computer system simultaneously. Sharing time or doing multiple tasks is a logical extension of multiprogramming. Processor time shared between multiple users simultaneously is called time sharing.

The main difference between Multi programmed Batch Systems and Time-Sharing Systems is that in the case of Multi programmed batch systems, the aim is to increase processor usage, and in Time-Sharing Systems, the aim is to reduce response time.

Many tasks are performed by the CPU by switching between them, but switching occurs frequently. Therefore, the user can get an immediate response. For example, in transaction processing, the processor uses each user's program with a short burst or quantum calculation. That is, if n users are present, each user can get a quantum of time. When a user submits an order, the response time is very few seconds.

The operating system uses CPU programming and multi-programming to give each user a small portion of time. Computer systems designed primarily as batch programs are converted to time-sharing systems.

The benefits of Timesharing applications are as follows :

  • It provides an opportunity to respond quickly.
  • Prevents software duplication.
  • Reduce CPU idle time.

The disadvantages of time-sharing apps are as follows :

  • The problem of honesty.
  • The question of the security and integrity of user programs and data.
  • Data connection problem.

Distributed operating system

Distributed systems use multiple medium processors to run multiple real-time resources and multiple users. Data processing tasks are still distributed between processors accordingly.

Processors communicate with each other through various means of communication (such as high-speed buses or telephone lines). This is called freely integrated systems or distributed systems. Distributed system processors may vary in size and performance. These processors are referred to the sites, nodes, computers, and so on.

The benefits of distributed programs are as follows :

  • With a resource sharing center, a user in one location can use existing resources in another.
  • Speed ​​up data exchange with each other via email.
  • If one site fails in a distributed system, the remaining sites may continue to operate.
  • Better customer service.
  • Load reduction on administrator computer.
  • Reduction of data processing delays.

Network Application

Network Operating System operates on a server and gives the server the ability to manage data, users, groups, security, applications and other communication functions. The main purpose of a network application is to allow shared file and printer access between multiple computers on a network, usually a local area network (LAN), private network or other networks.

Examples of network applications include Microsoft Windows Server 2003, Microsoft Windows Server 2008, UNIX, Linux, Mac OS X, Novell NetWare, and BSD.

The benefits of network applications are as follows :

  • Medium servers are very stable.
  • Security is managed by the server.
  • The development of new technologies and hardware can be easily integrated into the system.
  • Remote access to servers is possible from a variety of locations and types of systems.
  • Disadvantages of network applications are as follows -
  • High cost of purchasing and using the server.
  • Leaning on a central position for maximum performance.
  • Regular maintenance and renewal is required.

Real-Time App

A real-time system is defined as a data processing system where the time interval required to process and respond to input is too small to control the environment. The time it takes for the system to respond to input and display of new required information is called response time. So in this approach, response time is much shorter compared to online operations.

Real-time systems used where there are strict requirements for processor performance or data flow and real-time systems can be used as a control device in a dedicated application. The real-time application must have well-defined, set parameters, otherwise the system will fail. For example, Science experiments, medical imaging systems, industrial control systems, weapons systems, robots, aircraft control systems, etc.

There are two types of real-time applications.

Tough real-time programs

Complex real-time programs ensure that critical tasks are completed on time. In complex real-time applications, secondary storage is limited or non-existent and data is stored in ROM. In these applications, virtual memory is virtually unavailable.

Soft real-time programs

Soft real-time programs are not so limited. Serious real-time work is prioritized over other tasks and saves the essentials until you finish. Soft real-time systems have fewer uses than complex real-time systems. For example, multimedia, real truth, virtual reality etc.

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