Topic 3 Theory

Question 1

What are the different types of memory

Answer 1

Random-access memory (RAM)
Read-only memory (ROM)
Programmable Read-only memory (PROM)
Erasable Programmable Read-only memory (EPROM)
Electrically Erasable Programmable Read-only memory (EEPROM)
Flash memory

Question 2

Common properties of semiconductor memory

Answer 2

Exhibit two stable or semi-stable states, represent binary 1 and 0.
able to read and write.

Question 3

3 functional terminals of memory cell

Answer 3

Select, Control, Data in/Sense

Question 4

types of RAM

Answer 4

Dynamic and Static RAM

Question 5

Definition of Dynamic RAM

Answer 5

made with cells to store data as charge on capacitors.
DRAM requires periodic charges being refreshed to maintain data storage

Question 6

Definition of Static RAM

Answer 6

made with transistors with a flip-flop circuit.
Does not require periodic charges

Question 7

Similarities of SRAM and DRAM

Answer 7

they are both volatile

Question 8

Differences of SRAM and DRAM

Answer 8

DRAM are smaller,simpler to build, denser, less expensive and used in main memory.
SRAM are faster, more expensive and used in cache memory.

Question 9

Definition of hard failures in memory error.

Answer 9

Permanent physical defect
memory cells cannot reliably store data.
Happens due to harsh environmental abuse, manufacturing defects, wear and tear.

Question 10

Definition of soft error in memory error.

Answer 10

Random, non- destructive event alters contents of one or more memory cells.
No permanent damage to memory.
Power supply problems,alpha particles.

Question 11

Definition of Synchronous Dynamic Random Access Memory (SDRAM)

Answer 11

Exchange data with CPU synchronzied to a clock signal.
Run at full speed of data bus without wait states.
SDRAM uses a burst mode to eleiminate address setup.
data transfer synchronized to rising edge.

Question 12

DDR-SDRAM

Answer 12

doubles the data rate of regular SDRAM.
data transfer is synchronized to both rising and falling edge.

Question 13

Solid State Drives (SSD) vs Hard disk Drive (HDD)

Answer 13

SSD is made to replace HDD.
SSD Advantages over HDD.
High-performance I/O operations per second
Durable
Longer Lifespan
Lower power consumptions
Quieter and cooler
Lower access times and latency rates

Disadvantages
more expensive,
smaller storage capacity compared to HDD

Question 14

Practical issues of SSD

Answer 14

1. Tends to slow down along usages
2. Unusuable after a typical numer of 100,000 writes as lifetime of flash cell.

Question 15

Memory hierarchy among nonvolatile RAM

Answer 15

(Fast access time but more expensive, least bit density )
SRAM (cache), DRAM (main memory), NAND FLASH, and HARD DISK (external storage)