1.4 Types of Primary Memory

ROM (Read-Only) - Non-volatile
Small permanent memory that holds small program called the bootstrap - Looks for OS when "Booting"

RAM (Random Access Memory) - Volatile
Holds OS / Data / Programs that are IN USE.
Emptied when PC is switched off

Archiving and Backing Up

Archiving

• Archiving is done less frequently
• Cheap Media

Backing Up

• Is current Data that may be required immediately

e.g. The computer being used at a current time may crash and current data will need to be backed up for it to be recovered.

Random Access

• Follows an hashing algorithm to store every piece of data is stored in a specific location
• Very Fast
• If it is not complicated enough it can result in clashes

Index Sequential Storage

Visa (format)

XXX (400) = Visa +
X (0)= Country +
XX (12) = Bank +
XX = (34) Branch +
XXXX (5678) =
XXXX (9123)

• Quick Response

Seqential Storage

Structured way of saving and locating information

e.g. (A-Z), (0-1000000)
slower to save
quicker to locate