Memory, RAM, ROM, Cache Memory, Virtual Memory

 Memory

                            It is an internal storage area in the Computer System. The term Memory is used for physical memory, which refers to the actual chips capable to holding data. There is also a virtual memory, which expands physical memory onto a hard disk. 

Types of Primary Memory

 1. Volatile Memory- Volatile is a type of memory which stores data till power is on.

Ex.- RAM, VRAM, Cache memory.

Non- Volatile Memory- Non-Volatile memory is the type of memory which stores data permanently. It stores data until we don't delete or erase.

Ex.- ROM and Flash memory.

Types of RAM

1. SRAM (Static Random Access Memory)

2. DRAM (Dynamic Random Access Memory)

SRAM	DRAM
Fast	Slow
Costly	Cheap
Required 6 transistor to make one cell of memory	Required 1 transistor and 1 capacitor to make a cell
Ex- Cache Memory	Ex- Computer main memory, Graphic memory

 

Types of ROM

1. PROM (Programmable)- Manufacturer  writes data in this type of memory. No one can erase or modify data. Only can be read.

2. EPROM (Erasable)- If data is written in EPROM, it can be erased by ultraviolet rays using ROM Burner. We can Rewrite after erasing.

3. EEPROM (Electrically Erasable)- It can be erased using electric current. We can erase and re-write data without any other tools.

Cache Memory

                    Cache memory is the fastest memory. It is the type of SRAM. It is available on Processor and Hard Disk. It helps to process faster data. It stores executed instructions and their result.

Types of Cache Memory

• L1- 256kb
• L2- 1mb
• L3- 6mb

Virtual Memory

                                    Virtual memory is not a storage unit, it's a technique. Virtual memory increase the capacity of main memory. In Virtual memory, even such programs which have a larger size then the main memory are allowed to be executed.