Systems Software

Systems Software

1. Operating Software

   • User Interface
     • The user interface is how the user interacts with the system. This can be provided as part of the operating system or can be a separate program running on top of the operating system.
       • Windows® uses a graphical user interface (GUI) supplied as part of the operating system.
         • A GUI uses icons (small pictures) to represent the resources and actions, reducing the need to learn commands.
           • GUIs use mouse pointers or touch screens to select objects.

2. Utility Software

   • One or two tasks
   • Interacts with computers software
   • Stand alone or inbuilt to operating system
   • Examples
     • File Compression Disk Defragmentation File Repair Disk Copying Disk Formatting Disk Backup / Restore Anti-Virus
   • Lossless: Original file can be recreated and no data is lost
   • Lossy: Some of the original data is lost and the original file can not be re-created
   • Disk Defragmentation
     • When a hard disk drive 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 the gaps and become fragmented
     • Defragmentation software groups fragmented files back together
   • Encryption
     • Encryption means to scramble data in a way that it is unreadable to anybody who doesn’t have a key to be able to unscramble this.
     • Data is encrypted using a key and then decrypted using a key
     • Data is encrypted so that it is unreadable if anyone is to intercept it
   • Back-ups
     • Completed to ensure there is a way of restoring files/data/programs in case of computer failure
     • Copies of data and/or software are taken regularly and usually stored in a different location
       • Ensures that if computers are stolen or damaged in for e.g. a fire or a natural disaster that data can be restored and a company do not lose much money
     • Full
       • A copy of all data and software on the hard disk drive / server is copied to a backup medium (e.g. an external hard disk drive / DVD-R) and the medium is kept at a different location A copy of all data and software on the hard disk drive / server is copied to a backup medium (e.g. an external hard disk drive / DVD-R) and the medium is kept at a different location
       • Take a long time to complete (usually overnight)
       • Recovery takes a long time as it restores all data and programs
     • Incremental
       • A full backup is made initially
         • Each night only the files which have been changed since the last incremental back-up are copied
           • Much faster to complete that full back-ups
             • Takes much longer at restoring than a Full Back up as the full back up would need restoring first and then every incremental back-up since the last full back up