System Software
- Created by: HEPWORTH David
- Created on: 15-01-18 10:23
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- System Software
- Operating system
- Provides an interface between the user and the hardware
- Memory management
- Device drivers
- A piece of software used to control a piece of hardware
- Drivers allow a peripheral to device to be connected to a computer and be used in a Operating System
- Multitasking
- By giving the processor a small time slice for for each task means that all tasks appear to be to be executing at the same time
- To the user it appears that we can multitask and have lots of programs open at once
- In reality resources such as memory and the processor are being shared among tasks
- User interface
- How the user interacts with the Operating System
- Command line interface
- Text based
- E.g. DOS, Raspbian for Raspberry Pi
- Peripheral management
- Operating Systems manage the way in which hardware
- A peripheral is a piece of hardware that is not directly connected to the CPU such as a keyboard, mouse or hard disk
- Utility programs
- Utility programs are designed to do 1 or 2 tasks
- Utility software interacts with the computer's hardware e.g. the hard disk
- Utility programs are inbuilt into the Operating System
- Defrag
- When a hard disk is new files get added onto the disk in order very much like starting with a blank piece of paper and adding to it
- As files are deleted this leaves gaps
- When new files are saved the files fill in the gaps and become fragmented
- Defrag software groups fragmented files back together
- Backup
- Completed to ensure there is a way of restoring files/data and programs in case of a computer faliure
- Copies of data and/or software are taken regularly and usually stored in a different location
- Ensures that if computers are stolen or damaged e.g. a fire or natural disaster that the data can be restored and a company does not lose much money
- Incremental backups
- Each night only the files that have been changed since the last incremental backup are coppied
- Much faster to complete than full backups
- Takes longer at restoring than a full backup
- The full backup would need restoring first then the incremental backup since the last full backup
- Full backups
- A copy of all the data and software on the hard disk/server is copied to a backup medium e.g. an external hard drive/DVD-R
- Take a long time to complete (usually overnight)
- Recovery takes a long time as it restores all data and programs
- Encryption
- Encryption means to scramble data in a way that it is unreadable to anyone that doesn't have a key to be able to unscramble it
- Data is encrypted using a key and then decrypted using a key
- Data is encrypted so so it can be unreadable if anyone is to intercept it
- Compression
- Lossy
- Some of the original data is lost and and the original file can't be recreated
- Lossless
- The original file can be recreated and no data is lost
- Compression reduces the size of the file by performing an algorithm on the original data.
- Lossy
- Operating system
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