Storage

Storage

1. Primary

   • RAM
     • Random Access Memory
     • used as the main memory in a computer and it can be used to read and write to. RAM is volotile and needs power to maintain data. If the power is turned off, then RAM loses its contents.
     • RAM is slower than CPU cache but a lot faster than secondary storage
   • ROM
     • Read Only Memory
     • This tells the CPU how to boot up, ROM is non-volatile so doesn't need power to store the contents
     • ROM can only be read and not written to.
     • ROM comes on a small, factory-made chip built into the motherboard
     • As soon as PC is powered on, the CPU reads the instructions from ROM. This tells the CPU to: 1.) Perform self checks 2.) Set-up the computer eg. test the memory is working okay, see what hardware is present,copy the OS into the RAM

2. Secondary

   • Where all data is stored when not in use.
   • Things to look for when buying: Capacity, Read/Write speed, Portability, Durability, Reliability
   • Hard Disk Drives (HDD) are the traditional internal storage in PCs and laptops.
     • A hard disk drive is made up of a stack of magnitised metal disks spinning at a rate between 5400 and 15000rpm
     • Data is stored magnetically in small areas called sectors with circular tracks
   • Solid State Drive (SSD) have no moving parts. Most of them use a type of flash memory. SSDs have significantly faster read/write times than HDDS
     • Hybrid drives exist which use SSD for the OS and programs and a HD for less important data
   • Optical discs are things like: CDs 700MB, DVDs 4.7GB, Blu-Rays 25GB

3. Tertiary

   • Used for storing data for long term purposes. Mainly used for archives and back up.