MP CPCT Notes Part 4 - Computer Memory ,Types of Computer Memory ,Primary Memory, Secondary Memory, Cache Memory, Virtual Memory,

Computer Memory -

There are two types of computer memory. One is main/primary/internal memory and the other is secondary or auxiliary memory. Internal memory is the memory used by the computer's processor to run its applications, programs and operating system. This internal memory is often referred to as RAM, which stands for Random Access Memory.

The Other form of memory is the auxiliary memory which is where the computer will store information that is user generated. Examples of auxiliary memory are your hard disk your CD-ROM's and your DVD's.

Types of Memory -

Volataile Memory & Non-volatile memory

Volatile memory is computer memory that requires power to maintain the stored information , unlike Non-volatile memory which does not require a maintained power supply.

Primary Memory -

Primary memory is the memory that communicates directly with the cpu. Primary memory is made up of silicon chips. Primary memory has following two types.

1.Ram -

It stands for random access memory. This memory is accessed randomly, that is any byte of memory can be accessed without touching the previous sequence of bytes. Ram is the most common type of memory found in computers and other devices, such as printers. This memory generally loses its contents when you switch off the computer. This is why Ram is also known as volatile memory.

Types of Ram (Hardware) -

Commonly used RAM types

Static RAM (SRAM)
Dynamic RAM (DRAM)
Synchronous Dynamic RAM (SDRAM)
Single Data Rate Synchronous Dynamic RAM (SDR SDRAM)
Double Data Rate Synchronous Dynamic RAM (DDR SDRAM, DDR2, DDR3, DDR4)

2.ROM-

ROM Integrated chip on motherboard

It stands for Read Only Memory. Rom is designed to hold permanently stored programs installed by the computer manufacturer. Rom stores the start-up routine for the booting process and the diagnostic programs that check the computer hardware. The CPU can only read the instruction from ROM. It cannot write, erase or change the contents of ROM. Rom is non-volatile, meaning that when the computer is turned off, none of the information stored on the ROM is lost.

Types of non-volatile memory -

ROM -

It stands for Read Only Memor. It is a BIOS IC which is present on the motherboard.

PROM -

It stands for Programmable Read Only Memory. In this memory instruction's can burn once, then it is unalterable.

EPROM -

It stands for Erasable Programmable Read Only Memory. Memory instruction's in these memory can be reversed with the help of ultraviolet light.

EEPROM -

Electrically Erasable Programmable Read Only Memory. In this memory, burning process is reversible by exposure to electric pulses.

Secondary Memory -

When you want to keep data or information permanently, you need to transfer the data from primary memory to a magnetic disk or optical disk. Since primary memory is made up of silicon chips that is why is expensive than secondary memory and has less capacity than secondary storage. The device used to read or write data from the disk is called a disk drive.The main functions of the secondary storage devices are storage and retrieval. There are three common types of secondary storage devices - floppy disk, hard disk, hard disk, and CD- Rom.

Hard Disks -

Hard disk is a magnetic disk on which you can store computer data.Hard disks hold more data and are faster than floppy disks.Now-a-days, hard disks with capacity of 320 GB and 500 GB are common.

USB Pen Drives -

A USB pen/flash drive is a data storage device that includes flash memory with an integrated USB interface. It is typically removable, re-writable and much smaller than an optical disc.

Floppy Disks -

Floppy disk is a soft magnetic disk. It is called floppy. Floppy disks are portable because they can easily be carried from one place to another. Disk drives for floppy disks are called floppy drives. Floppy disks are slower to access than hard disks and have less storage capacity. Now a days is not used widely.

Compact Disk (CD) -

The compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony to store and play digital audio recordings. It was released in 1982 branded as Digital Audio Compact Disc.

Digital Video Disk (DVD) -

Stands for "Digital Versatile Disc." A DVD is a type of optical media used for storing digital data. It is the same size as a CD, but has a larger storage capacity. Some DVDs are formatted specifically for video playback, while others may contain different types of data, such as software programs and computer files.

Blue Ray Disk -

The Blu-ray Disc (BD), often known simply as Blu-ray, is a digital optical disc storage format. It is designed to supersede the DVD format, capable of storing several hours of video in high-definition video.

Solid State Drive -

A solid-state drive is a solid-state storage device that uses integrated circuit assemblies to store data persistently, typically using flash memory, and functioning as secondary storage in the hierarchy of computer storage.

Cache Memory -

Cache Memory: Cache memory is the small size of RAM inside the processors. This cache memory is SRAM (Static RAM) unlike the DRAM (Dynamic RAM) which we find in normal RAM. This SRAM is quite fast compared to DRAM. In computers, we find different levels of cache memory .

Virtual Memory -

In computing, virtual memory, or virtual storage is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a very large memory".

Thanks for reading, Have a good day !

Read MP CPCT Notes Part 1 - Familiarity with computer system

Read MP CPCT Notes Part 2 - Computer Input Devices

Read MP CPCT Notes Part 3 - Computer Output Devices

Read MP CPCT Notes Part 5 - Computer Hardware Components

Read MP CPCT Notes Part 6 - Software, software Categories.

Read MP CPCT Notes Part 7- Computer Languages, Memory Units