A Level Computing

A Level Computing

1. RAM & ROM

   • RAM
     • Stores data files currently in use, application software, OS
     • Volatile
     • Short term memory
     • Can be read or written from
     • Needed when: The user is required to enter data. The processor requires RAM as working memory/buffer. Data can be loaded into the RAM for the current program in use.
   • ROM
     • Non volatile
     • Example: Bootstrap which runs OS on start-up
     • Stores control software on devices that require standard processing
     • Read Only, Cannot be altered
     • Needed when: Application processing follows a standard pattern e.g. Burglar alarm. Program instructions are standard each time and do not need to be changed. It's important that the user cannot alter the instructions.

2. Operating System

   • The OS controls the operations of the hardware and resources management. It controls the data flow around the system and also the storage devices.
   • Human Computer Interface - Allows user control the OS and the computer hardware, allows communication between user & hardware.
   • The OS provides a platform for applications to run and it deals with issues that the software may have e.g. Storage of files
   • Handles Communications using rules/protocols to govern them
   • Handles translation of code
   • Utility Programs
   • Controls Security