1.2 Memory Kwaku

1.2 Memory Kwaku

1. Virtual Memory

   • Simulated memory on the hard drive
   • Holds apps on CPU that RAM can't support
   • Lots more memory to be used than there is in the system
   • 1. Sets up memory using Virtual Memory Manager
     • 2. VMM creates a file on the hard disk
       • 3. OS can then address memory
         • 4. Swapping or Paging is used by OS to move data between RAM and Virtual Memory
           • 5. OS moves the data

2. ROM

   • Considered permanent and secure as you can't erase data and it is offers security against accidental/ malicious damage
   • Holds instructions for booting-up the computer
   • Data is pre-written and comes with computer
   • Data is permanently written

3. RAM

   • Random Access Memory
   • Volatile Storage
   • If not saved, when power is turned off it is emptied
   • DRAM - Dynamic RAM.
     • A chip that is dependant on power to keep saved sata
   • SRAM - Static RAM
     • Faster DRAM with less power needed
   • Holds cache, OS, apps and GUI
   • Stores programs currently in use and data currently in use

4. Flash Memory

   • Found in USB drives and memory cards
   • Advantages include:
     • Very reliable as no parts move
       • Won't break if dropped or exposed to heat
         • Compact and stores a lot of data in a small space
           • Very fast access time to a hard disk or DVD
             • Low cost and reliable
               • Easily portable
   • Disadvantages include:
     • easily lost as it is so small
       • Wears out over a period of time
         • more expensive than a DVD or CD
           • Metal part can be bent or damaged
   • retains data in the absence of a power supply.
   • Is needed

5. Solid State

   • Doesn't move
   • A drive that uses non-volatile memory as a means of storing and accessing data

6. POST

   • BIOS
     • Basic Input/Output System
     • The chip performs checks
   • Power on Self Test
   • Checks that components like peripheral devices are present and functioning correctly
   • Once checks completed, CPU starts OS
   • If checks fail, it shows error message

7. Storage

   • Volatile
   • Non-volatile