primary memory

• Memory is the component of the computer that holds data, programs and instructions that are currently in use.
• Primary memory is built inside the computer. As a result, data can be read from and written to primary memory extremely quickly. This gives the processor fast access to the data and instructions that the primary memory holds.
• • ROM (read only memory) is non-volatile, whereas RAM (random access memory) is volatile. Non-volatile memory keeps its contents even when the computer is switched off. Volatile memory loses its contents when unpowered.
  • Primary memory is comparatively limited in size, especially when compared with secondary storage. In a modern personal computer, primary memory is often around 4 GB in size.
• Why do you need primary storage?

  • access times faster than secondary so time taken to complete operations eg fde cycle is reduced
  • holds the data & instructions that CPU needs to access whilst the computer is turned on
  • Due to the fast access times, primary storage is used as short term, working memory, in hardware that is directly connected to the CPU such as RAM, and components that reside inside the CPU such as Cache and Registers
  • Performance = higher cost which limits amount used eg RAM is usually 16 or 32 gigabytes whereas secondary storage such as a hard drive is in terabytes