primary and secondayry storage

• secondary storage is a permanent store of data and instructions that are not currently in use by the processor
• solid state storage is a non-volatile storage medium that contains no moving parts
• storage reliabilty is the number of read/write cycles a storage device can complete before it fails
• magnetic storage uses surfaces coated with a layer of magnetic material on which data can be stored magnetically setting the arrangement of the material
• optical storage is a medium that uses discs on which data is stored as pits and lands. it is then read by a laser
• primay storage is memory that the CPU can read/write to quickly
• RAM(random access memory) is volatile and can be read from and written to
• ROM(read only memory) is non-volatile and contains BIOS
• BIOS (basic input output system) is instructions that are needed to boost up the computer
• virtual memory is used to store data once the RAM is full. Data is then transferred between the virtual memory and the RAM when the data is needed by the CPU
• volatile means power is required for the component to retain data
• non-volatile means the component always retains data regardless of if there is power or not
• secondary storage is non-volatile storage where programs are kept for late use
• flash drives and memory cards

  solid state storage used to expand the capacity of small devices
• optical discs


  eg CDs can be read only, write-once or rewritable
• magnetic tape


  used by organisations to store huge amounts of data
• external HDDs and SSDs


  portable versions of external storage. Often used for backups
• magnetic storage :magnetic parts move over the disks surface to read and write data magnetically
• optical storage :lasers read and write data using light
• solid state storage: data is stored onto solid memory chips without any moving parts
• optical storage advantages: cheap, portable, small size
• optical storage disadvantages: low capacity, easily damaged, slow write speeds
• solid-state storage advantages: cheap, portable, robust, small size
• solid-state storage disadvantages: expensive, small size allows them to be easily misplaces
• best capacity = magnetic
• best speed = solid state
• best portability = solid state
• best durability = solid state
• best reliablity = solid state
• best cost = magnetic