RAM

Question 1

RAM

Random Access Memory

Answer 1

• Most important component (speed, speed, speed)

- Data & Programs can only run when moved to RAM

Question 2

ROM

Read Only Memory

Answer 2

• Good place for BIOS
• Cannot be changed or erased
• PROM = Programmable ROM (only once)
• EPROM = Erasable PROM (write, erase, write again)
• EEPROM = Electronically erasable PROM
  
  • Flash Memory & SSD

Question 3

Static RAM

SRAM

Answer 3

• Very fast
• Very expensive
• Very big memory (size)
• Used often in processor caches
  
  • L1, L2, & L3

Question 4

Synchronous Dynamic Access Memory

SDRAM

Answer 4

• Single Data Rate (SDR)
• Synchronous DRAM (SDRAM) - 168 pins
• SDRAM is synchronous with system clock
  
  • Que up one process while waiting for another
  • Classic DRAM didn’t wait for a clock signal

Question 5

Dynamic Random Access Memory

DRAM

Answer 5

• Dynamic
  
  • Needs constant refreshing
  • Without refreshing, memory disappears

Random Access

 - Any storage location can be accessed directly
 - Unlike magnetic tape

Question 6

Dual Inline Memory Module

DIMM

Answer 6

• Electrical contacts are different on each side
• 64 bit data width
• DDR SDRAM - 184 pins
• DDR2 & DDR3 SDRAM - 240 pins

Question 7

Small Outline Dual Inline Memory Module (Laptops)

SO-DIMM

Answer 7

• Used for laptops - 68mm X 32mm
• DDR & DDR2 SDRAM - 200 pins
• DDR3 SDRAM - 204 pins

Question 8

Micro Dual Inline Memory Module

Micro-DIMM

Answer 8

• Smaller form factor for mobile devices
• 54mm X 30mm
• Higher memory density
• DDR - 172pins
• DDR2 & DDR3 - 214 pins

Question 9

Double Data Rate

(DDR) SDRAM

Answer 9

• Twice the data rate as SDR (Ordinary)
  
  • Performs at the same clockspeed

-184 pins

• DDR - 200 = 200 million transfers per second
  
  • Multiply by 8 to get throughout in megabytes (MB/s)

-200 X 8 = 1,600 = PC1600

Question 10

Double Data Rate 2

(DDR2) SDRAM

Answer 10

• Faster speeds
  
  • Twice as fast as DDR

-240 pins

• Not backwards compatible
  
  • Won’t work in DDR slots

-400 X 8 = 3200 = PC2-3200

Question 11

Double Data Rate 3

(DDR3) SDRAM

Answer 11

• Twice as fast as DDR2
  
  • Larger chip capacities
• 240 pins
• Not backwards compatible

Question 12

Parity Memory

Answer 12

• Adds an additional parity bit
• Won’t always detect a problem or error
• Cannot correct error

Question 13

Error Correcting Code

ECC

Answer 13

Detects & Corrects errors on the fly

• Not all systems use ECC
  
  • Looks the same as non-ECC memory

Question 14

Registered Memory

Buffered Memory

Answer 14

• Includes an additional registered between the RAM module & the memory controller
• Used mostly on servers
• More stable operating environment

Question 15

Multi-Channel Memory

Answer 15

• Installed in pairs or trios for the max throughput
• Memory combos should match
• Memory module slots are colored differently