1.2.1

• RAM can be read from and written to. It is volatile - it loses data if the power is turned off. Any part of RAM can be accessed in the same amount of time. It is much faster to access than a hard drive. When the OS, software applications, documents and files are opened they are copied from secondary storage to RAM.
• ROM (Read Only Memory) is used to store data that needs to be held permanently in primary storage. Data is read from ROM but not written to it. It is non-volatile.
• ROM is used to store:

  • The initial program that is run when the computer is turned on. This is known as the bootstrap loader
  • The Basic Input/Output System (BIOS)
  • It performs the Power-On Self-Test (POST) to make sure there are no issues
  • It loads the OS into RAM
  • It takes care of drivers to allow control of the computer hardware
  • It has a configuration program that allows you to configure system settings
• RAM vs ROM

  A) Yes

  B) Yes

  C) Yes

  D) Yes

  E) No

  F) No

  G) BIOS and bootstrap

  H) Running programs and OS

  
• If RAM is full, the OS creates virtual memory using a section of the hard drive. Programs are transferred out of RAM and into virtual memory. The OS prioritises which programs currently need to be in RAM. This process is ongoing. Virtual memory is not ideal but necessary to keep the computer functioning efficiently. Increasing RAM would be a better option.
• Advantages of virtual memory:

  • Uses cheap secondary storage on the hard drive
  • Prevents error messages saying 'out of memory'

  Disadvantages of virtual memory:

  • Accessing virtual memory is very slow - this will reduce the computer's speed performance when switching between programs
• Memory is necessary as it contain the instructions that the CPU follows. It also holds data and programs that are currently in use.
• Primary storage is needed to:

  • Hold data, programs and instructions that are currently in use
• Volatile memory is temporary memory. It requires power to retain its data
• Non-volatile is permanent memory- it keeps its contents even when it has no power
• RAM is often referred to as the main memory. It can be read from and written to. RAM is volatile. It is faster to access than hard drive and the CPU can access any part of the memory in the same amount of time.
• RAM is where all data, files and programs are stored while they're being used. When a computer boots up, the operating system is copied from secondary storage to RAM. When software applications, documents and files are opened, they are copied from secondar storage to RAM. They stay in RAM until the files or applications are closed.
• ROM is non-volatile memory. It can only be read, not written to. It contains all the instructions a computer needs to properly boot up.
• ROM is used to store the initial program that is run when the computer is turned on. This is known as the bootstrap loader. It stores the Basic Input/Output System (BIOS)

  • Performs the Power-On Self-Test (POST)to make sure there are no issues
  • It loads the Operating System into RAM