System Software Unit 7 – OCR Computer Science GCSE

1.7 System Software:


Purpose of system software:

System software is software designed to run and main a computer:

Operating System: This is a complex piece of software found a computer

Functions of the Operating System:

-Communicates with internal and external hardware by device drivers. Peripheral management is making sure that the correct piece of data goes to the correct piece of external hardware.

-Provides a user interface, allowing a user to interact with the computer: Graphical User Interfaces are the most common. They are designed for everyday users as they are visually interactive.  A command-line interface is text based. This is less resource heavy than GUIs. They are not suitable for everyday users but for more advanced users as they are more efficient and powerful. They can be used to automate processes using scripts.

-Allow the computer to multi-task by controlling memory resources and the CPU. Multi-tasking is the ability of running multiple applications at the same time.

-Deals with file management and disk management The OS seals with the movement, editing and deletion of data.

-Manages the security of the system. For example, through user accounts.

Utility software:

Defragmentation software – Reorganizes data on the hard drive to put fragmented files back together. It also moves files to collect all the free space together. This helps to prevent further fragmentation. After the hard drive has been defragmented, the computer will have an increase in performance as the time it takes to read data from the disk will take less time as everything is now organized.

-Back up: This is a copy of a computer’s system’s files and settings stored externally. This means the data can be recovered in the event of data loss.

A Full Back up is where a copy is taken of every file on the system. They often use a lot of storage space. A full backup can take a long time to create but it is faster to restore from.

An Incremental back up are where the files that have been created, edited or modified in any way since the last backup is copied. They use less storage space and much quicker to create. But, a full system restore is slow, the last full backup must be restored, followed by every incremental backup since that point.

Encryption Software – This scramble data to stop third parties from accessing it. Encrypted data (cipher text) can be decrypted by an encryption key.

Compression software – This reduces the size of files so that they take up less disk space. It is used often on the internet to make files quicker to download.

There are two types of compression:

Lossy Compression: Greatly reduces file size but lossy compression loses data, the file can’t be reverted back into the original.

Lossless compression: Data is only removed temporarily so there is no reduction in quality. However, it is on a slight reduction in file size.

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