Operating Systems

Why do you think that Operarting Systems are necessary in order for a computer to run effectively?

The OS (Operating System) ensures that all the software has access to the different resources it need to run successfully and controls the running and scheduling of all these processes and manages the share of the Central Processing Unit's processing time that is used by the different processes, making the computer run effictively.

Explain four tasks performed by an Operating System?

Functions Of Operating System
Today most operating systems perform the following important functions:
1. Processor management, that is, assignment of processor to different tasks being performed by the computer system.
2. Memory management, that is, allocation of main memory and other storage areas to the system programmes as well as user programmes and data.
3. Input/output management, that is, co-ordination and assignment of the different output and input device while one or more programmes are being executed.
4. File management, that is, the storage of file of various storage devices to another. It also allows all files to be easily changed and modified through the use of text editors or some other files manipulation routines.

5. Establishment and enforcement of a priority system. That is, it determines and maintains the order in which jobs are to be executed in the computer system.
6. Automatic transition from job to job as directed by special control statements.
7. Interpretation of commands and instructions.
8. Coordination and assignment of compilers, assemblers, utility programs, and other software to the various user of the computer system.
9. Facilities easy communication between the computer system and the computer operator (human). It also establishes data security and integrity

There are many different brands of Operating System. Identify four of the most common ones.

Linux

Windows

Lion

IOS

Explain how an Operating System can manage numerous people working at the same time. What is this called?

An operating system can manage numerous people working on at the same time becasue of the following features.

MULTI-USER:This allows one or more user to log into a system. Thus the operating system must contain a user account database, which contains user name, default home directory, user passwords and user right.

MULTIPROCESSING:This allows two or more processes to be used at a time. Here the operating system must decide if it can run the different processes on individual processors. It must also manage the common memory between processors

MEMORY MANAGEMENT:This involves allocating, and often to create a virtual memory for program. Paging which means organizing data so that the program data is loaded into pages of memory. Another method of managing memory is swapping. This involves swapping the content of memory to disk storage.

MULTI-THREADING:Processes are often split into smaller task, named threads. This thread allows smoother operations

Utility programs provide a "toolbox" of common tasks which help the computer to run more effeciently. Identify and explain three utilities that are available.

Anti-virus utilities scan for computer viruses.

Backup utilities can make a copy of all information stored on a disk, and restore either the entire disk (e.g. in an event of disk failure) or selected files (e.g. in an event of accidental deletion).

Data compression utilities output a shorter stream or a smaller file when provided with a stream or file.

Disk checkers can scan operating hard drive.

 Explain the difference between the three different methods of processing and provide and example of each

Batch Processing
•This is a method where the information to be organized is sorted into groups to allow for efficient and sequential processing.

Online Processing
•This is a method that utilizes Internet connections and equipment directly attached to a computer. It is used mainly for information recording and research.

Real-Time Processing
•This technique has the ability to respond almost immediately to various signals in order to acquire and process information.

Distributed Processing
•This method is commonly utilized by remote workstations connected to one big central workstation or server. ATMs are good examples of this data processing method.
For each of the following tasks that can be performed on a computer, state whether they would be a job for the operating system or an application;




Controlling the engine management for a car                Application

Writing a letter                                                                Application

Backing up the system                                                    Operating System

Calculating company accounts                                          Application

Allocating memory to allow programs to run                   Operating System

Writing a report                                                              Application

Communication with a partner                                           Application