Modes of operation
Computers can operate in many different ways requiring different and complex operating systemThe software that manages the hardware and software resources in a computer system..
Real-time processing
When the computer has to react within a guaranteed time to an inputData which is inserted into a system for processing and/or storage., a real-time operating system (RTOS) is used. For example, the engine management system within a car uses a real-time operating system in order to react to feedbackInformation used to modify performance. from sensorA device that measures a physical quantity and converts it into a signal to be read and interpreted. placed throughout the engine.
A real-time operating system does not necessarily have to be fast. It simply has to be quick enough to respond to inputs in a predictable way. Embedded computers often contain an RTOS as many are used to control something.
Computers operating in real time are often dedicated to the control of systems such as industrial processes, planes and space flights.
Multi-programming
Multi-programming is a method of operating such that several programSequences of instructions for a computer. appear to be running at once.
The operating system switches jobs in and out of processorShorthand for central processing unit (CPU). time according to priority. For example, while one job is being allocated printer time, another will be being processed in memoryThe part of a computer that stores data.. The processor is so fast that it seems that many jobs are being processed at the same time.
Batch processing
A batch processing system is where programs or data are collected together in a batch and processed in one go. Typically the processing of payrolls, electricity bills, invoices and daily transactions are dealt with this way.
This method of operation lends itself to jobs with similar inputs, processing and outputData which is sent out of a system. where no human intervention is needed. Jobs are stored in a queue until the computer is ready to deal with them. Often batch processed jobs are done overnight.
Interactive processing
An interactive processing system is where the tasks on the computer system require a continual exchange of information between the user and the computer system. It can be seen as the opposite of batch processing.
Multi-tasking
This isn't just about running more than one applicationA software program that allows a user to perform a specific task. at the same time. Multi-tasking allows multiple tasks to run concurrently, taking turns using the resources of the computer.
This can mean running a couple of applications, sending a document to the printer and downloadingTo copy a file from the internet onto your computer or device. a web pageAlso known as webpage. A page designed for, and viewed in, a web browser..
Multi-access or multi-user
Modern personal computers can allow multi-user access. A multi-access (or multi-user) system is one where several users can use the same system together via a LANLocal area network. A network of computers that covers a small area, eg a school or college..
The CPU/processorCentral processing unit - the brain of the computer that processes program instructions. deals with users in turn; clearly the more users, the slower the response time. Generally, however, the processor is so fast that the response time at the most is a fraction of a second and the user feels they are being dealt with immediately.