Computing - 1.2 Memory and storage

• 1.2.1 What are the features of primary storage?

  - Very quick because it is directly accessed by the CPU

  - include RAM and ROM
• 1.2.1 What are the features of secondary storage?

  - Slower because it is not directly accessed by the CPU.

  - Used for the long-term storage of data and files because it is non-volatile.

  - includes magnetic, optical and solid-state storage.
• 1.2.1 Explain the difference between volatile and non-volatile storage. State an example of both types

  - Volatile storage is temporary-data is lost whenever the power is turned off. Example: RAM

  - Non-volatile storage saves the data even when not being powered. Data can be stored long-term and accessed when the computer is switched on. Example: ROM
• 1.2.1 Explain why the computer requires primary storage

  Program instructions and data must be copied from the hard drive into RAM to be processed by the CPU because primary storage access speeds are much faster than secondary storage devices like the hard drive.
• 1.2.1 Describe random access memory and state what information is stored within it

  RAM is volatile (temporary) storage that stores all programs that are currently running. RAM also stores parts of the operating system to be accessed by the CPU.
• 1.2.1 Describe read-only memory and state what information is stored within it

  ROM is non-volatile storage that cannot be changed.

  ROM stores the boot program / BIOS for when the computer is switched on. The BIOS then loads up the operating system to take over managing the computer.
• 1.2.1 Describe virtual memory and state what information is stored within it

  Programs must be stored in RAM to be processed by the CPU. Even if there is insufficient space in RAM for all programs the computer can use the hard disk drive (HDD) as an extension of RAM - this is called virtual memory.
• 1.2.2 What is meant by secondary storage?

  Secondary storage is non-volatile storage used to save and store data that can be accessed repeatedly.
• 1.2.2 What are the 6 storage characteristics?

  Capacity, durability, portability, cost, reliability, access speed
• 1.2.2 What is meant by the term magnetic device?

  Magnetic devices such as hard disk drives use magnetic fields to magnetise tiny individual sections of a metal spinning disk
• 1.2.2 What are the magnetic storage characteristics?

  - large capacity and cheap cost per gigabyte than solid state

  - not durable and not very portable

  - slow access speed but faster than optical storage
• 1.2.2 What is meant by the term optical device?

  Optical storage devices, such as CD, DVD and Blu-ray discs. Optical devices use a laser to scan the surface of a spinning disc made from metal and plastic. The disc surface is divided into tracks, with each track containing many flat areas and hollows.
• 1.2.2 What are the optical storage characteristics?

  - low capacity

  - not durable because discs are very fragile and can break or scratch easily

  - discs are thin and very portable. also cheap to buy in balk

  - have the slowest access speed
• 1.2.2 What is meant by the term solid state device?

  Solid-state devices use non-volatile random access memory (RAM) to store data indefinitely. Solid-state storage devices, such as solid-state drives and USB memory sticks
• 1.2.2 What are the solid state storage characteristics?

  - high capacity but more expensive cost per gigabyte than magnetic

  - usually durable

  - very portable because the USB sticks are small

  - has the fastest access speed because they contain no moving parts