chapter 4

Question 1

what are the 2 types of ram

Answer 1

static
- bits stored as 1, 0 switches
-no charge leaks
-no refreshing of circuits

dynamic
- bits stored in charged capacitor
- refresh circuits
-slow & inexpensive

Question 2

explain rom

Answer 2

-read-only-memory
-permanent data pattern
-no power supply to maintain data bits
-no room for error

Question 3

explain programmable rom

Answer 3

• written electrically with special equipments
• less expensive, non-volatile, flexible

Question 4

explain erasable prom

Answer 4

• erasable process is done repeatedly
• expensive but multiple update capability

Question 5

explain electrically erasable prom

Answer 5

• erase using electric
• erase without removing prior contents
  -non-volatile & flexible

Question 6

explain flash memory

Answer 6

• intermediate between eprom & eeprom
  -electrical erasing technology
  -single erase process due to organized microchip (block memory)

Question 7

what are the error correction?

Answer 7

1. hard failure
   - permanent damage to memory
   -physical defect
   - drop, wear down, harsh environment
2. soft error
   - no permanent damage to memory
   - random
   - power supply, short circuit

Question 8

what is synchronous DRAM

Answer 8

• synchronized with external clock signal during data exchange with processor
• runs full speed with processor bus without imposing wait status
  -processor issues instructions latched by DRAM
  -DRAM response after a set number of clock cycles
  -processor does other tasks

Question 9

what is double data rate SDRAM

Answer 9

• 3 ways at achievhing high data rates
  1. synchronization of data transfer with falling & rising edge
  2. utilize high clock rate to increase transfer rate
  3.utilize buffering scheme