Computer memory types are divided into two categories – primary memory and secondary memory. As you already know in primary memory we have RAM (Random Access Memory) and ROM (Read Only Memory).
Whats in it for me?
- What are primary and secondary memory?
- Types of primary memory.
- RAM and ROM.
- Types of Random Access Memory.
- Variety of ROM.
- Types of secondary memory.
- Speed of memory.
- Unit of memory.
Let’s jump into computer memory types.
What are the primary and secondary memory?
As the name primary memory, this means that it’s used in the first place.
Therefore, the CPU can directly communicate with primary memory.
The speed of primary memory is very fast. Primary memory has cache memory and main memory (Random access memory and read-only memory).
This memory used in second place. CPU cannot communicate directly with secondary memory.
In secondary memory, we have Hard disk, floppy disk, magnetic tape, etc. Secondary memory is cheap in price as compared to the primary memory and the speed of secondary memory is also slower.
Types Of Primary Memory
Primary memory are divided into two categories:
A. Cache Memory
B. Main memory
Cache Memory – Computer Memory Types.
The cache memory is the CPU’s internal memory. CPU cache use (static random access memory). This means that it doesn’t have to constantly refresh.
Copies of data and instructions are stored in cache memory from the ram that’s waiting to be used by the CPU. In short, it holds the common data that is used by the CPU over and over again.
Because when the CPU needs certain data it first checks in the cache memory to see if the data is there if it’s not there the CPU uses slower memory RAM to access the data.
The main reason for using a cache is to make computers fast at a low price. If the cache is not used then it creates a bottleneck to feed the data to the CPU.
In short, cache memory is a mediator between RAM and CPU to feed data to CPU a lot faster.
CPU cache comes in 3 different level – Computer Memory Types.
Level 1 – Level 1 cache is also known as the primary cache located on the processor. Runs at a similar speed as the processor.This is the fastest cache on the computer
Level 2 – Level 2 cache is used to catch recent data accessed by the processor that was not stored in level 1 cache. In a nutshell if the CPU doesn’t find the data in level 1 cache then it looks forward to level 2 cache.
In earlier computers cache was located on a separate chip on the motherboard but now its locates on the processor.
Level 3 – If the processor cannot find the data in level 2 cache then it looks the
data in the last level of cache which is level 3 cache.
Also, level 3 cache is used to catch recent data accessed by the processor that was not stored in level 2 cache.
If level 3 doesn’t have the data then it looks forward to the ram. It’s larger than
level 2 but not as fast as level 2.
Main Memory (RAM AND ROM)
Main memory is of two types – computer memory types.
i. RAM – Computer Memory Types.
The long-form of RAM is random access memory. It is used to store data temporarily.CPU can access data directly from RAM. Most important in computer memory types.
RAM is a volatile memory by volatile memory I mean that RAM can retain the data till the power(electricity) is supplied to it. When the power is cut off all the data in the RAM are erased.
Whenever you open a program, software, or song it first loads into the ram and then processed by the CPU. RAM is a bit expensive as compared to secondary storage and the speed of RAM is fast then the secondary memory.
RAM chips are installed in a module called DIMM (Dual Inline Memory Module) and it’s mounted on a PCB (printed circuit board).
DIMM can have 168,184,240or 288 pins in it. DIMM is installed on the motherboard on the memory slots the average motherboard have 2 or 4 memory slots
ii. ROM – Computer Memory Types.
ROM (Read-only memory) is an IC kind of thing that is mounted on your computer motherboard.
Read-Only Memory is a non-volatile memory. Therefore, it can retain the data with or without the supply of power (electricity). For example – if your pc is turned off the data in the ROM will not be erased.
ROM is used to store the BIOS ( Basic input-output operating system)/firmware, therefore, all the important instructions that used to start the computer are programmed.
The most important thing is the majority of the time this data is only used to read, that’s why it’s called read-only memory.
Types of RAM – Computer memory types.
RAMS comes in different types
DRAM (Dynamic Random Access Memory)
DRAM is a memory that contains capacitors. For example – the capacitor is like a box containing electricity.
These capacitors store the information in bits such as 0 or 1 and due to capacitors DRAM has to refresh continuously because capacitors cannot hold the charge for a long time they regularly lose current.
SDRAM (Synchronous dynamic random access memory)
Now this memory is commonly used in PCs This ram has flip flop to store data and also has capacitors like DRAM
But the difference between these rams is synchronization. Also, this ram runs synchronizing With the system clock. All signal is tied to the system clock for better controlling time.
Types of ROM – Computer Memory Types.
MROM (Mask read-only memory) –
This type of read-only memory can be written only one time means you can fill instructions (data) in it only one time but the data can be write-only by the company.
This was used in the earlier days of computers. Now it not used it is the cheapest option but it is not easy to write data in it
PROM (Programmable read-only memory) –
In this also data can be written only one time but in this user can also write the data. Also, this is designed blank. For example, you have used Compact disk CD-R in around 2008 this PROM Used in early stages.
EP–ROM (Erasable programmable read-only memory ) –
in this ROM you can do both write and erase data but in this high UV(ultraviolet) light are used to erase data. Hence, it’s costly.
EEP-ROM (Electrically erasable programmable read-only memory) –
In this you can write and erase data electrically. Nowadays this is the most used ROM. surely if you are working on pc your pc has 1. So, now you can read and write BIOS yourself.
Types of secondary memory
Secondary memory uses three main technologies to store data.
- Magnetic storage.
- Optical storage.
- Solid-state storage.
Magnetic storage –
Magnet is used to store data. Some examples of magnetic tape are –
Magnetic Tape – Cassette is used to store data.
Magnetic DIsk – Hard disk (HDD) and Floppy Disk used to store data.
Optical storage –
Similarly this an optical disk is used to store data. Hence, in this, we use the burn method to store data some example of the optical disk are –
CD – Compact Disk (700MB)
DVD – Digital Versatile Disk(4.7GB)
BRD – Blu Ray Disk(25 – 50GB)
HVD – Holographic Versatile Disk(6TB)
Solid-state storage –
The most important thing is in this semiconductor is used to store data. In fact, in this, we use the Flash method to store data some example of Solid-state storage are –
SSD – Solid State Drive
Speed of memory (RAM) –
Before I tell you about the speed of RAM. Firstly you have to understand the 32 bit and 64-bit data path it means the number of bits transferred in 1 clock cycle.
Of course, the more the data is transferred in one clock cycle the faster the computer would be. In short, 32 bit means 32 bit in one clock cycle and 64 bit means 64 bit in one clock cycle.
In earlier computers, there were SIMMs (single inline memory modules) used. They have 32-bit data path Now DIMMs is used they have 64 Bit data path and that’s why they are faster than SIMMS.
For example – A single bit or 1 bit of data is the smallest form of data that computers read.
also, 8 bits = 1Byte and 64-bit data path means 64/8 = 8byte wide bus
TYPES OF RAM ACCORDING TO SPEED
SDRAM – in earlier times the late 90s labeled as 100MHz .100Mhz means the speed at which the ram operates and has an 8-byte wide channel.
So the speed of RAM is 100 MHz x 8 bytes(64bit) = 800MB/s.
Another type of memory called RDRAM they developed the RIMM(Rambus inline memory module) has 184 pins and looks similar to DIMMs but the notches located at the center of the module.
They run at 800MHz but they have only a 2-byte wide bus thus the speed of RDRAM was 800 MHz x 2 Byte = 1600 MB/s.
DDR -After that, a new ram technology is developed called DDR(double data rate).The most important thing is DDR sends a double amount of data in each clock cycle by using both rising and falling edges to send data.
Units of speed of RAM. – Computer memory types.
DDR RAM label includes both the clock speed and bandwidth in its name.
For example – if ram labeled as DDR-333 PC-2700 then this means 333MHz x 8byte = 2700MB/s
DDR2 – the technology that succeeded DDR is DDR2. It is faster than DDR because it has faster bus speed and it also uses less power than DDR it has240 pins
DDR3 – right after DDR2 DDR3 comes in the market and its twice as fast as DDR2 and it uses less power as compared to DDR 2
DDR4 – it has 288 pins and uses less power DDR4 offers a higher speed than DDR3.
For example – DDR4-4266 PC4-34100 have speed of 34100MB/s
ECC – In some cases, data corruption cannot be tolerated. For example, in bank servers, govt servers. Therefore, ECC is introduced.
The most important thing is ECC detect the data was correctly processed by the memory module and make it correct if it needs to.
you can identify the ECC RAM by counting the chips in the RAM normal RAM has 8 chips while ECC ram has 9 chips. It mostly used in servers.
so, the computer memory types is explained.
Unit of memory –
|BIT||it can store only 0 or 1 . it’s the smallest memory.|
|NIBBLE||4 bits makes a nibble|
|BYTE||8 bits make a byte|
|KILOBYTE(KB)||1024 bytes makes a KB|
|MEGABYTE(MB)||1024 KB makes a MB|
|GIGABYTE(GB)||1024 MB makes a GB|
|TERABYTE(TB)||1024 GB makes a TB|
|PETABYTE(PB)||1024 TB makes a PB|
|EXABYTE(EB)||1024 PB makes an EB|
|ZETABYTE(ZB)||1024 EB makes a ZB|
|YOTTABYTE(YB)||1024 ZB makes a YB|
|BRONTOBYTE||1024 YB makes a BRONTOBYTE|
|GEOPBYTE||1024 BB makes a GEOPBYTE|
in short computer memories are divided into two categories primary memory and secondary memory. Primary memory also divided into two categories main memory and cache memory.
So basically, the cache is the fastest memory in which important files data are saved and the main memory has RAM and ROM. Secondary memory have HDD.
I hope, you understand computer memory types well. If yes do a comment and tell us. Or have a doubt let us know in the comment section.
Also read – computer input devices.
RAM and ROM and cache are the main memory of the computer.
Computer memory is a device that is used to store data. Also, it has two types of memory, primary memory and secondary memory.
Without a memory computer can’t run, memory holds the instructions used to start the computer.
Cache is the temporary memory of the computer.
Computer memory is measured in BYTES.
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