Memory and its Types

     What is Computer Memory? 

   Ans: A Computer memory is just like a human brain. A human Brain store data and information also like a  Computer memory store data and information. It is a physical device capable of storing information temporarily or permanently. In other words, it is called a storage space or like a storage container where we are store data and information. 
  There are two types of Computer Memory: Primary Memory and Secondary Memory
    1. Primary Memory: Primary memory is a volatile memory. It is stored only those data and instructions when a Computer is currently on. It is a small storage capacity memory and data is lost when the computer power is switched off. 
     Primary memory primarily three types:
     i. Cache Memory: Cache memory is a very high-speed memory. It acts as a buffer between the main memory and the CPU.

1. It is the fastest memory of the computer system.
2. It is inbuilt in the processor.
3. It is a supplementary of RAM.
4. It is also called CPU memory

ii. Random Access Memory(RAM)

1. Random Access Memory.
2.  It is the Main Memory.
3. Temporary Memory.
4. Volatile Memory.
5. It is display Memory
6. It is sometimes called physical memory.

Types of RAMs: DRAM (Dynamic RAM) and SRAM (static RAM)

DRAM:

1. DRAM requires periodic refreshment.
2. It is slower and dynamic in nature.
3. More power consumes and cheaper.

SRAM:

1. SRAM retains data bits without periodic refreshment.
2. It is slower and dynamic in nature.
3. More periodic refreshment.

iii. Read Only Memory(ROM):

1. Read-Only Memory.
2. It is called BIOS Chip.
3. It is a permanent memory.
4. Non Volatile Memory.
5. It is also called Firmware.
6. It performs the Booting Process and POST process.

Types of ROM:- PROM, EPROM, EEPROM.

PROM:-Programmable Read Only Memory.

EPROM:-Erasable Programmable Read Only Memory

EEPROM:- Electronically Erasable Programmable Read Only Memory.

2. Secondary Memory:

Secondary Memory:-It is where programs and data kept on a long-term basis. It is a large volume storage device. It is also called permanent memory and Auxiliary memory.

Example: Hard Disk Drive, CD, DVD, etc.

HDD:- Hard Disk Drive –(40GB, 80GB, 500GB,1TB)

FDD: Floppy Disk(1.44MB)

CD:- Compact Disk(700MB)

DVD:- Digital video Disk Digital Versatile Disk (4.7GB)

SD Card :- Secure Digital (1GB, 2GB, 4GB, 8GB,16GB, 32GB, 64GB)

PD:-Pen Drive (1GB, 2GB, 4GB,16GB, 64GB)

On the Basis of storing Technique, memory is three types:

1. Magnetic Memory :(Use tiny magnetic spots.)It is two types:

a. Magnetic Tape (Analog Data –Reel used in camera and Cassettes.) and

b. Magnetic Disk (Digital Data- Floppy Disk, Hard Disk)

2. Optical Memory: (Tiny hole pits on reflective metal layer coated in plastic). Example:- CD, DVD

3. Semi-Conductor Memory: (Uses transistor and registers for storage). Example: ROM, PROM, and RAM.

Another Kind of Memory is :

Flash Memory: Flash memory is a kind of memory that retains data in the absence of power supply.

Example:- Semiconductor memory, PD, SD Card, etc.

Unit of Memory :

Bit- Binary digit (0,1)

4 Bit                                    =       1 Nibble

8 Bit                                    =        1 Byte

1024 Byte                           =        1 Kilo Byte

1024 KB                             =        1 Mega Byte

1024 MB                             =        1 Giga Byte

1024 GB                             =        1 Tara Byte

1024 TB                              =        1 Peta Byte

1024 PB                              =        1 Exa Byte

1024 EB                              =        1 Zeta Byte

1024 ZB                              =        1 Yotta Byte

1024 YB                              =        1 Bronto Byte

1024 Bronto Byte               =        1 Geop Byte

1024 Geop Byte                 =        1 Sagan Byte

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