Computer Memory Systems

Question 1

+What types of memory are there?

Answer 1

Internal ( main memory, cache ) and External Memory ( optical disks, tapes )

Question 2

Capacity of memory

Answer 2

Number of Words
Number of Bytes

Question 3

Unit of Transfer - memory

Answer 3

Bits ( main memory)
Word
Blocks

Question 4

Access Method of memory

Answer 4

Sequential Access (linear sequences) - Tape Units

Direct Access - Disk Units

Random Access - Main memory, Cache systems

Associative Access - Cache System

Question 5

Performance of memory

Answer 5

Access time (latency)
Cycle Time
Transfer rate (1/cycle time)

Question 6

Physical Type of memory

Answer 6

Semiconductors
Magnetic
Optical
Magneto-optical

Question 7

Physical Characteristics of memory

Answer 7

Volatile/non-volatile
Erasable/non-erasable

Question 8

Memory design:

Answer 8

Greater Capacity - -Lower Cost per unit
Greater Capacity - Slower Access time
Faster Access time - Greater Cost

Question 9

Memory Hierarchy - Main Memory > Storage > Magnetic Storage

Answer 9

• Decreasing cost per bit
• Increasing capacity
• Increasing access time
• Decreasing frequency of access of the memory by processor

Question 10

Cache Memory

Answer 10

Combine fast and expensive memory with less expensive and lower speed.

Cache contains a copy of portions of memory.

Question 11

Multiple level cache organisation

Answer 11

CPU to Level 1 Cache, Level 2 Cache, Level 3, Main Memory.

As you go down the memory access is slower and slower.