Memory (i)

Storage Media Classification:
1. Semiconductor storage device, small size, low power consumption, short access time, the loss of information when the power supply disappears. is a volatile memory.
2. Magnetic surface Memory
It is non-volatile to read and write with the magnetic head on the surface.
3. Core memory
Not easy to lose, large volume, large power consumption.
4. Disc memory
The use of laser to read and write, non-volatile.

Classification by Access mode:
1. Random memory RAM, different storage principle is divided into, static RAM, dynamic RAM
2. Read-only memory Rom:
Mrom Mask read-only memory, masking process according to user requirements, information recorded in the chip
Prom programmable read-only memory
EPROM erasable Programmable read-only memory
EEPROM electrically erasable Programmable read-only memory
Flashmemory Flash, has eeprrom features, faster than it.
3. Serial Access memory
To read and write to the storage unit, you need to find the address in the order of physical location.

Classification of functions in computers

Main memory, secondary memory, buffer memory

Main memory exchange information directly with CPU. The secondary storage is used to store data that is currently temporarily unused and cannot be exchanged directly with the CPU.

Compared to: main memory speed, small capacity, high price.
Secondary storage speed is slow, large capacity, low price.

The hierarchy of the storage device

The higher the level, the faster it gets.

Cache main memory, main memory secondary storage

Set up cache to augment main memory, solve speed mismatch problem

Memory (i)