Comp 01 1.2 memory + storage

what is secondary storage

non-volatile

permanent storage of data

RAM v ROM

RAM - bigger, read + write, volatile

ROM - smaller, read only, non-volatile

what is stored on RAM

parts of operating system in use

currently running software/ data

what is virtual memory

overflow of RAM in hard drive

used when RAM runs out of space

pushes programs not in use into VM

swaps them back in when they are needed

cheap secondary storage + prevents error message

However is very slow

What is stored on ROM

Bootstrap - initial program used when turned on telling computer where to find operating system

BIOS - controls processor speed + system time

characteristics, advantages + disadvantages of magnetic storage with examples

mechanical parts move over disks to read + write data magnetically

adv - cheap, large capacity, fast write speed

dis - not portable, not durable

e.g. hard disk drive, floppy disk

characteristics, advantages + disadvantages of optical storage with examples

lasers read + write data using light

adv - cheap, portable

dis - low capacity, low durability, slow write speeds

e.g. CD, DVD, blu-ray

characteristics, advantages + disadvantages of solid state storage with examples

data is recorded onto solid memory chips with no moving parts

adv - durable, fast

dis - more expensive but similar capacity to magnetic

e.g. SSD, USB flash drive, SD card

6 storage characteristics

capacity

speed

portability

durability

reliability

cost per GB