Introduction to Computer Memory

Study Notes

Primary Memory: The main memory of a computer.
- Used to store data and instructions the CPU needs to access quickly.
ROM (Read Only Memory): A non-volatile memory.
- Used to store important information for system operation.
- Data cannot be changed or erased.
- Examples include digital washing machines and ovens.
PROM (Programmable Read Only Memory):
- Data stored in it is permanently stored and cannot be changed or erased.
EPROM (Erasable Programmable Read Only Memory):
- Data in EPROM can be erased and reprogrammed by ultraviolet light.
- Reprogramming capability is limited compared to EEPROM.
EEPROM (Electrically Erasable Programmable Read Only Memory):
- Can be programmed and erased electrically.
- Data and programs can be erased and reprogrammed about ten thousand times.
RAM (Random Access Memory):
- The primary memory of a computer.
- RAM stores data temporarily.
- Data is lost when the power is turned off (volatile).
- Types of RAM:
  - SRAM (Static Random Access Memory): Stores information as long as power is supplied, faster than DRAM, used in cache memories, consumes less power and generates less heat.
  - DRAM (Dynamic Random Access Memory): Stores data that CPU needs for its task, requires constant refreshing to maintain the data, commonly seen as Main Memory
  - SDRAM (Synchronous Dynamic Random Access Memory): synchronizes itself with the computer's system clock. Speed is measured in MHz instead of nanoseconds which makes it faster.

HDD (Hard Disk Drive): Used to store large amounts of data.
- Consists of platters (disks) coated with magnetic material.
- Storage capacities range from 256GB to 2TB.
SSD (Solid State Drive): Works like a super-fast hard drive.
- Stores data on memory chips.
- High speed and reliable electronic storage.