Computer memory is such a hardware among all types of memory devices that it stores Data in the form of permanent or temporary basis. Generally, We know data is stored permanently for future use but what is meant by temporary data storage memory? Let me explain…….
First, we have to know why computer uses different types of memory or data storage devices. The computer is such an electronic device that performs task depending on instructions that were given previously. As instructions are given before it can process anything, so it should be kept in secure place so that it would not be changed in future. This work is done in ROM(Read Only Memory) that can’t be changed over time. Every task is done by processor placed on the motherboard of a computer. The processor takes input and process following a certain instruction stored in ROM.
As the speed of the processor is very fast than any other memory speed, so general memory is not suitable for the processor to exchange data quickly with respect to processor speed. RAM(Random Access Memory) which is fast compared to general memory is an appropriate memory to be done with this requirement.
When we run any program or application, it is loaded into RAM. RAM sends data to the processor and takes feedback from the processor. RAM and ROM are used for processing but if want to store any data comes from an external device or after being calculated, then we need non-volatile memory which can store data even in unplugged condition.
So, that discussion was about basic need of memory. Now we’ll know in short how computer memory works.
The computer always works in binary mode which has only two logic (0,1). All works are done by binary data when it takes input, process and gives output. Computer memory is divided into small parts called the cell. Every cell is made to store 1 or 0 and has a unique address. When any document is to be stored, it is converted to binary and stored in a specific address.
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Different Types of Memory
There are two types of memory-
- Internal memory.
- External memory.
Internal Memory is placed inside PC, so it is called Internal Memory. It provides working space. It is either volatile memory(temporary in nature) or non-volatile memory(Permanent in nature). It is of several types-
- CPU Register: It is made of a collection of high-speed registers which performs arithmetic, logical, control and input/output operation. This is most speedy memory among memory devices.
- Cache Memory: Cache memory is placed inside CPU or outside near to CPU which stores data that recently and frequently used by CPU. When CPU use instructions frequently from RAM, it is placed in cache memory so that instructions can be accessed at more speed. So, consumed time is very less for cache memory compared to RAM. It is a hidden memory and not accessible by software. It is controlled by the hardware itself. Cache memory size can be 2KB to 8MB. It has several levels-
- L1 Cache(2KB-128KB): This is primary cache memory which is placed inside CPU. It is smaller in size but faster in speed.
- L2 Cache(256KB-512KB): This is secondary Cache memory which is placed outside CPU but with the motherboard. If CPU does not find instruction in the L1 cache then it tries to find in L2 Cache. This is bigger than L1 Cache.
- L3 Cache(1MB-8MB): This is also a secondary Cache memory. Its size is more and speed is less than L2 but more speed than RAM.
- RAM(Random Access Memory): RAM is such a volatile memory that stores data and instruction of a program when it is run. When power is absent, it remains blank not storing any information. Programs cannot send any instruction to CPU when it is in storage memory, so it should be in RAM memory then it would use CPU. When we close program execution, then it is removed from RAM automatically. To speed up your PC read this article- Does The RAM size affect the speed of your PC | How much RAM you really need
There are several types of Random Access Memory-
- SRAM(Static RAM): This type of RAM is static in nature, it is not refreshed periodically dislike DRAM. When power is gone, it also remains blank. It is used to make cache memory. So, it is faster than any other memory. It requires four or six transistors to store one bit only. Power consumption is very low.
- DRAM(Dynamic RAM): This type of RAM is used as a primary memory. It needs to be refreshed periodically. It can’t store any information when power is not present.
- T-RAM(Thyristor-RAM): This is made of Thyristor. A new technology invented in 2009 is implemented on this device which is a combination of SRAM and DRAM. It is faster than ordinary RAM.
- Z-RAM(Zero-Capacitor RAM): It is realized from the name, there is no capacitor. Innovative Silicon claims that- It is so fast as SRAM and a transistor of Z-RAM will give same speed like six transistors of SRAM. It is not marketed yet broadly.
- ROM(Read Only Memory): This is a non-volatile memory which is used to store firmware or application software permanently. It can keep information stored inside while power off mode. But if we want to change files stored in ROM, it can’t be done like other memory or limited opportunity to change. The computer only reads from this memory but can’t write as its name means that. It’s the main purpose is to control or supervise Computer in a certain manner.
It is also of several types:
A. MROM(Mask ROM): This is programmed by the manufacturer only and not by the user of the computer. Even it can’t be changed by the user if any bug is detected. Then there is no way to replace. If the program is not finalized, it must not be entered into MROM.
B. PROM(Programmable Read Only Memory): Yeah, it can be programmed by the user. Every bit is locked with either fuse or anti-fuse. But if the program is written one time, it can’t be changed further.
C. EPROM(Erasable Programmable ROM): This ROM can be re-store data after erasing previous data. This can be done in two ways:
D. UEPROM(Ultraviolet EPROM): Ultraviolet radiation is used to erase data stored in EPROM.
E. EAEPROM(Electrically Alterable EPROM) or EEPROM: Erasing data is done by an electrical signal. Data is stored permanently in this ROM also but it can be changed by Electrical Signal. EEPROM is used for modern days mobile, tab etc electronic device.
This type of memory is attached to the computer from outside and used to store any types of information of the user. Every external memory is non-volatile types of memory.
Different types of External Memory is used as conventional storage. Some are described here:
- Magnetic Storage: It stores information by means of magnetism. It is mainly used for audio and video recording purpose. Most of them are the analog type.
- Floppy Disc: Floppy disk has one moving plate. Data is written on the disc surface. The storage capacity of the floppy disc is very low and it is the portable type memory device. The average size of the floppy disc is 1.44MB.
- Hard Disc Drive(HDD): This has also a moving disc inside and a read/write head to write or read data from disc surface in a magnetic way. R/W head access only 1 or 0. It stores information permanently but it can be deleted or replaced by another file when needed. The user can manage this.
- Solid State Drive (SSD): This is same as Hard disc but it has not any moving parts or read/write head to move on. SSD is couple time faster than HDD. As processor sometimes needs to retrieve information from Hard Drive (i.e. while booting from HDD), HDD should be more speedy for better user performance. But the speed of HDD(highest 150MBPS) is very less. In this time, SSD is the best solution as its speed is up to 550MBPS.
- Optical Storage: Optical storage contains a disc where data is written by laser light beam. i.e. CD, DVD, Blu-ray Disc. It is of two kinds- (i) Read-only type and (ii) both read/write types.
- Solid State Storage: This really means certain types of EEPROM and non-volatile memory device where information can be read or write. Information is not destroyed if the user does not change.
- External HDD: This is also called portable Hard disc. Generally, the Hard disc is attached as internal parts but this Hard disc is inserted usually by USB or eSATA port externally even can be connected by a wireless medium. It can be used by any computer. It comes to market in different shapes and size such as passport, mobile size etc.
- Smart Cloud Devices: Like external HDD, it is also portable type memory device where any information from any device can be stored, it may be mobile, tab, netbook, laptop etc. but it needs an internet connection to access files.
Now we have to decide which memory device is perfect for your Computer after knowing all the stuff about different types of memory. There is no choice for internal storage like CPU, register, RAM but There are plenty of options for external devices. Sometimes it will cost you more money but gives you greater performance.