GCSE Computing - Software

GCSE Computing - Software

1. Operating Systems

   • Doesn't require a Kernel
     • Security
       • The operating system must be able to distinguish between legitimate program requests and illegitimate ones and it does this by authenticating each request
     • Pheripheral Managment
       • A piece of hardware that interacts with the computer
         • E.g. a keyboard or a monitor
     • User Interface
       • It is essential for human interaction
       • The OS provides controlling the functons of the computer without resorting to machine code
   • Requiers a Kernel
     • Memory Managment
       • It's role is to safely allow access to the memory that programs require.
       • It prevents multiple programs interfering with the same memory
         • E.g. You cannot edit a file while it is open
     • Multi-tasking
       • Instead of process happening one after the other, the kernel allows programs to work overlapping by allowing the programs control over the CPU and memory
     • Application --> Kernel
       • <-->CPU
       • <-->Devices
       • <-->Memory
       • Kernel
         • Is a program that manages the tasks of the computer and hardware

2. Utility Programs

   • Security
     • Antivirus
       • A program thet detects and eliminates malicious software
     • Firewall
       • A network system that controls and filters incoming and outcoming traffic
     • Spyware Protection
       • Spyware is a software that gathers and sends information about the host.
         • E.g. trojans
       • Most spyware protection programs simply block the threat or try to eliminate it.
   • Disk Organisation
     • Formatting
       • This is the process of partitioning sections of secondary storage before file storage
     • File Transfer
       • This allows files to be moved around, copied and deleted by the user, easily
     • Defragmentation
       • Defragging a disk reorganises related data, so they are accessed quicker
         • Data can be scattered on different sections of the har disk
   • System Maintenance
     • System clean-up tools
       • This speeds up performance by deleting old files
     • System information and diagnostics
       • The specifications of the harware are kept and can be checked to see if they are functioning correctly
     • Automatic Updating
       • This searches online, finds, downloads and installs the software when a new update has been released

3. Types of Software

   • Off-the-Shelf
     • These are programs you can buy that are aimed at meeting lots of needs
     • Relatively cheap
     • Thoroughly tested, usually bug free.
       • Lots of help available
   • Open Source
     • A type of software with the source code freely available for anyone to use and modify
       • Modify it to own needs
     • (Usually) free
   • Costum Written
     • A program that is comissioned to specifically meet the users needs
       • So it works and meets the needs perfectly
     • Takes a long time to build
     • Could be expensive
     • No help available
   • Propietary
     • Sometimes referred to as a 'closed-source'
       • Because no source code is available to the public
         • No changes can be made to the software
     • Commercially availabe but with licences
     • Not free
       • Although updates are usually free
     • Complete testing
     • May not be specific to needs