Software

Software

1. Refers to the programs we run on our computer - the programs are the stored sets of instructions given to the processor to carry out. It also refers to the data that is used by the proograms

2. Types

   • Utility Software
     • Has limited functionality and is used to maintain computer systems
   • Application Software
     • Handles real-world jobs that users want to do
   • System Software
     • Operating System
       • Functions
         • Memory Management
           • The OS manages the transfer of data between the CPU, RAM and main storage
         • User Interface
           • The OS provides the user with a way of controlling the functions of the computer without resorting to machine code
             • Command line interface (CLI) e.g. MSDOS. Commands can be grouped into shell scripts to carry out maintenance jobs
             • Graphical (GUI) e.g. Windows. Uses icons to represent actions. No commands have to be learned.
           • Acts as a boundary between human and machine
           • The interface lets users give commands, ask questions and display a response
         • Peripheral Management
           • The OS manages the input and output devices connected to the computer, like a keyboard, mouse and printer
         • Multi-tasking
           • The OS allows more than one program to be run at once so users can switch between applications easily
         • Security
           • The OS provides security features to restrict access to the system or particular files
     • Controls hardware and acts an an intermediary between application and hardware (hides complexities and allows user to operate computer without writing programs

3. Utility Programs

   • Security
     • Anti-virus
       • Detects and protects the computer against virus threats and quarantines infected files
     • Firewall
       • Restrict communication in and out of the computer from the applications that are running
     • Spyware protection
       • Detects and removes spyware (small programs that quietly monitor what you are doing)
   • Disk Operations
     • Formatting
       • Sets up a hard drive, memory stick or card into a format that the computer can use to store/retrieve data. the process of formatting erases any data that was previously on the storage medium
     • File transfer
       • Allows movement of files from one location to another, either locally or via memory stick
     • Defragmentation
       • Re-organises the data on the hard drive to improve read/write access time
   • System Maintenance
     • System info and diagnosis
       • Provides information about the system in order to help with diagnosis of problem
     • System cleanup tools
       • Removes temporary files and compresses/archives unused files to increase free storage
     • Automatic updating
       • Uses the Internet to check the OS is up-to-date and applies software patches/fixes as necessary

4. Translators

   • Compiler
     • Translates all code at once, fast but prone to error
   • Assembler
     • Converts assembly code into machine code
   • Interpreter
     • Translates line by line, is slow, can check for mistakes

5. Library programs

   • Collections compiled routines which are shared by multiple programs
     • Printing fucntion
     • Interfaces (i.e. all Microsoft software has a similar interface)
     • Graphic engines of computer games

6. Virtual machine

   • Links hardware applications and the user but hides the true complexity of the computer from the user and other software