1.3 RAM

Question 1

What is ROM?

Answer 1

ROM (Read-Only Memory). Can’t be changed or erased.

Question 2

What is PROM?

Answer 2

PROM (Programmable Read-Only Memory), can write once.

Question 3

What is EPROM?

Answer 3

EPROM (Erasable Programmable ROM), can write, erase, and write again.

Question 4

What is EEPROM?

Answer 4

EEPROM (Electronically Erasable PROM). Flash Memory and SSD.

Question 5

What is SRAM?

Answer 5

Static Ram (SRAM) 
Fast, Large, and Expensive RAM. Often used in processor caches. (L1, L2, or L3 Cache)

Question 6

What is DRAM?

Answer 6

DRAM (Dynamic RAM), the RAM we know and love. Dynamic requires constant refreshing or data is lost. Doesn’t wait for a “clock signal”

Question 7

What is SDRAM?

Answer 7

SDRAM (Synchronus Dynamic RAM) Double speed of SDR RAM without changing clock.

Question 8

What is SDR SDRAM?

Answer 8

SDR RAM (Single Data Rate SDRAM), Synchronized with the common system clock. 168-pin. 1 chunk of data per cycle.

Question 9

What is DDR RAM?

Answer 9

DDR RAM (Double Data Rate RAM), Twice the Data Rate of SDR (ordinary) RAM. Able to send data on “rise” and “fall” of clock cycle. 184-pin.

Question 10

What is DDR2, DDR3, DDR4 RAM?

Answer 10

2x as fast as original DDR at the same clock speeds. 240-pins.

DDR3 is 2x as fast as DDR2, DDR 4 is 2x as fast as DDR3. Each iteration is incompatible with the previous.

Question 11

Memory Clock Speed

Answer 11

How fast the clock is set within the memory itself.

Question 12

I/O Bus Speed

Answer 12

How fast the bus is outside of the memory. (whatever the memory is connected to and its speed).

Question 13

DDR Speed

Answer 13

How many transfers the memory can do per second. (ex: DDR3-800 = 800 million transfers per second.)