Memory

Memory

1. ROM

   • ROM is Read Only Memory. ROM is memory that cannot be changed by a program or user. ROM retains its memory even after the computer is turned off. For example, ROM stores the instructions (BIOS) for the computer to start up when it is turned on again this is called the boot sequence. ROM cannot be overwritten by the computer. ROM is needed for the computer to turn on.

2. RAM

   • RAM is Random Access Memory. RAM is a fast temporary type of memory in which programs, applications and data are stored. The operating system, applications and the graphical user interface are all examples of what is stored in RAM, it stores data currently being used by the computer.
   • The more RAM there is in a computer the more processes it can carry out at one time, meaning there is less need for using virtual memory. When there is not enough RAM to store the data, some of the data is moved to the hard drive where it is slower to access. So having more RAM will mean that the computer can process more data which means data will not have to be accessed from the hard drive so programs will run quicker. It will also improve multi-tasking capabilities

3. Differences between ROM and RAM

   • RAM is volatile whereas ROM is non-volatile, so data stored in ROM is retained even when power is turned off whereas data stored in RAM is lost when the computer is turned off.
   • Data can be written to the RAM.
   • A ROM is mainly used in the start up process of a computer, whereas a RAM is used in the normal operations of a computer after starting up and loading the operating system.

4. Virtual Memory

   • When RAM is full and more instructions are needed to be stored, part of the hard disk is temporarily used to store the data, this is called virtual memory. it is used when there is not enough main memory to run the programs required.

5. Cache Memory

   • Cache memory is part of the processor it is part of the memory that a computer can access more quickly than it can access regular RAM.