Information Technology [3 Mark Questions]

Multi-Tasking Operating System
The OS that allows the execution of multiple tasks at one time is known as multi-tasking OS. In this type of OS, several applications may be simultaneously loaded and used in the memory. While, the processor handles only one application at a particular time. It is capable of switching between the applications effectively,
e.g. Unix, Windows 2000/XP/NT/Vista etc.
Multi-User Operating System
It is the type of OS that allows many users to take advantages of the computer’s resources, simultaneously. This OS makes sure that the requirements of the various users are balanced and each of the programs they are using has sufficient and separate resources, i.e. problem with one user doesn’t affect the entire community of users.
e.g. Unix, Linux, Windows 2000 etc.

A real-time operating system has well defined fixed time constraints.
Process must be done within the defined constraints otherwise the system will fail. OS for a flight control computer or an advanced Jet airplane is the example of a real-time operating system.
Often used as a control device in a dedicated applications such as controlling scientific experiments, medical imaging systems, industrial control systems and some display systems.
Real-time operating system can be classified as follows:
Hard real-time operating system It is the OS which can guarantee the maximum time for the operations it performs.
Soft real-time operating system It is the OS which cannot guarantee the maximum time for the operations it performs.

Memory Management
It is the act of managing computer’s primary memory or main memory. Main memory is a large array of words or bytes where each ward or byte has its own address. Main memory provide a fast storage that can be accessed directly by the CPU.
An operating system does the following activities:

• It keeps track of the status of each memory location either allocated or free.
• Each process must have enough memory to execute and it cannot run into the memory space of another process.
• Allocates the memory when a process requests it to do so.
• De-allocates the memory when a process no longer needs it or has been terminated.

In most of the computers, it is possible to add memory beyond the original capacity, e.g. you might expand RAM according to your system configuration and requirement. Partitioned allocation divides primary memory of computer into multiple memory.

Storage Management
It is the process, which describes the technologies and processes used by a computer to improve the performance of its data resources.
The data or files will be stored into the computers in such a way that an authorised user can easily access and use it. It is a wide process which includes virtualisation, replication, security, compression of data, traffic analysis etc.
It helps to improve the visibility control and automation for data and storage. Most programs including compilers, assemblers, Word processors etc., are stored on a disk until loaded into main memory and then, use the disk as both the source and destination of their processing. This entire process is handled by the operating system itself.

An operating system is a system software that acts as an interface between the user and hardware resources. It controls and co-ordinates the hardware used by various application programs. OS acts as resource allocator and manager. Since, there are many possible conflicting requests for resources, the OS must decide which requests are allocated resources to operate the computer system efficiently and fairly. An OS is a control program, which controls the user programs to prevent errors and improper use by the computer. It is especially concerned with the operation and control of I/O devices.
Main functions of an OS are as follows:

• Processor management
• Memory management
• File management
• Device management
• Storage management