System Software

System Software

1. Utility Software

   • Utility programs are designed to do just one or two tasks
   • Utility software interacts with the computers hardware E.g. the Disk Drive
   • Utility programs can be stand alone but are also inbuilt in to the Operating System
   • Utility software
     • File Compression Disk Defragmentation File Repair Disk Copying Disk Formatting Disk Backup / Restore Anti-Virus
   • 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
     • 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 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

2. Operating Software

   • Utility Programs
     • Disk Defragmentation tool, anti-virus software, disk copier/ formatter, data compression
   • User managment
   • Peripheral managment
     • When a peripheral is required, a signal, called an interrupt, is generated to signal to the operating system that it needs to deal with something. This tells the CPU to stop the running process as soon as it can and to deal with another process linked to the peripheral device. These programs are called device drivers.
   • Memory managment
     • When a program is running it must be in the computer’s main memory and the operating system must manage where in memory each program and the data it needs must go.
   • Multi-tasking
     • While the CPU waits for other actions to complete, e.g. loading data to RAM, it works on other tasks