(RAM) Random Access Memory 

Computer memory or random access memory (RAM) is your system's short-term data storage; it stores the information your computer is actively using so that it can be accessed quickly.

RAM,   where information is stored temporarily when a program is run. Information is automatically pulled into memory, we can't control this. RAM is cleared automatically when the computer shutdown or rebooted. RAM is volatile( non-permanent ).

• What kind of memory is RAM?

Random Access Memory (RAM) is primary-volatile memory and Read Only Memory (ROM) is primary-non-volatile memory. It is also called as read write memory or the main memory or the primary memory. The programs and data that the CPU requires during execution of a program are stored in this memory

Types Of (RAM) Random Access Memory 

 Mainly there are two types of RAM are used  they are    

1. Dynamic Random Access Memory (RAM)

👉Stands for "Dynamic Random Access Memory." DRAM may be a sort of RAM that stores every little bit of knowledge on a separate capacitance. this is often associate economical thanks to store knowledge in memory, as a result of it needs less physical house to store a similar quantity of knowledge than if it had been hold on statically. Therefore, a DRAM chip will hold a lot of knowledge than associate SRAM (static RAM) chip of a similar size will. However, the capacitors in DRAM got to perpetually be reinvigorated to stay their charge, thus DRAM needs a lot of power than SRAM.

Still, as a result of DRAM will hold a lot of knowledge than SRAM and since it's considerably more cost-effective to manufacture, DRAM is that the commonest sort of memory found in notebook computer systems. whereas there square measure many varieties of DRAM on the market, the foremost common kind is synchronous DRAM SDRAM, that may be a quicker version of ordinary DRAM. this is often the kind of memory most computers use for his or her main system memory.

If you decide on to upgrade your computer's SDRAM, check your machine's necessities to envision if the memory modules should be put in in pairs. If so, you'll got to replace 2 modules promptly and that they should be a similar size (i.e. 2 1GB SDRAM memory modules).

1. Static Random Access Memory (RAM)

SRAM or Static Random Access Memory may be a kind of semiconductor memory wide employed in natural philosophy, chip and general computing applications. this way of semiconductor memory gains its name from the very fact that knowledge is command in there in a very static fashion, and doesn't got to be dynamically updated as within the case of DRAM memory. whereas the info within the SRAM memory doesn't got to be rested dynamically, it's still volatile, that means that once the ability is faraway from the device, the info isn't command, and can disappear.

SRAM basics

There square measure 2 key options to SRAM - Static random Access Memory, and these set it out against different forms of memory that square measure available:

The data is command statically: this implies that the info is command within the semiconductor memory while not the necessity to be rested as long because the power is applied to the memory.

SRAM memory may be a kind of random access memory:   A random access memory is one within which the locations within the semiconductor memory are often written to or scan from in any order, despite the last memory location that was accessed.

The circuit for a personal SRAM memory cell contains generally four transistors organized as 2 cross coupled inverters. during this format the circuit has 2 stable states, and these equate to the logical "0" and "1" states. additionally to the four transistors within the basic memory cell, and extra 2 transistors square measure needed to regulate the access to the memory cell throughout the scan and write operations. This makes a complete of six transistors, creating what's termed a 6T memory cell. generally any transistors square measure wont to provide either 8T or 10T memory cells. These further transistors square measure used for functions like implementing further ports in a very register file, etc for the SRAM memory.

Although ANy 3 terminal switch device are often employed in an SRAM, MOSFETs and specially CMOS technology is often wont to make sure that terribly low levels of power consumption square measure achieved. With semiconductor recollections extending to terribly giant dimensions, every cell should win a awfully low levels of power consumption to confirm that the general chip doesn't dissipate an excessive amount of power.

SRAM memory cell operation

The operation of the SRAM memory cell is comparatively easy. once the cell is chosen, the worth to be written is hold on within the cross-coupled flip-flops. The cells square measure organized in a very matrix, with every cell singly available. Most SRAM recollections choose a complete row of cells at a time, and browse out the contents of all the cells within the row on the column lines.

While it's not necessary to possess 2 bit lines, victimisation the signal and its inverse, this can be traditional observe that improves the noise margins and improves the info integrity. the 2 bit lines square measure passed to 2 input ports on a comparator to alter the benefits of the differential knowledge mode to be accessed, and therefore the tiny voltage swings that square measure gift are often a lot of accurately detected.

Access to the SRAM memory cell is enabled by the Word Line. This managements the 2 access management transistors that control whether or not the cell ought to be connected to the bit lines. These 2 lines square measure wont to transfer knowledge for each scan and write operations.SRAM memory applications

There square measure many various forms of semiconductor memory that square measure accessible lately. selections got to be created concerning the proper memory sort for a given application. presumably 2 of the foremost wide used sorts square measure DRAM and SRAM memory, each of that square measure employed in processor and pc situations. of those 2 SRAM may be a very little costlier than DRAM. but SRAM is quicker and consumes less power particularly once idle. additionally to the present SRAM memory is simpler to regulate than DRAM because the refresh cycles don't got to be taken under consideration, and additionally to the present the method SRAM are often accessed is a lot of specifically random access. an extra advantage if SRAM is that it's a lot of dense than DRAM.

As a results of these parameters, SRAM memory is employed wherever speed or low power square measure issues. Its higher density and fewer difficult structure conjointly lend it to use in semiconductor memory situations wherever high capability memory is employed, as within the case of the memory inside computers.

Some other RAMS square measure

(a) EDO (Extended knowledge Output) RAM : In Associate in Nursing EDO RAMs, any memory location are often accessed. Stores 256 bytes data} information into latches. The latches hold next 256 bytes of data in order that in most programs, that square measure consecutive dead, the info square measure accessible while not wait states.

(b) SDRAM (Synchronous DRAMS), SGRAMs (Synchronous Graphic RAMs) These RAM chips use identical clock rate as CPUuses. They transfer knowledge once the central processor expects them to be prepared.

(c) DDR-SDRAM (Double rate – SDRAM) : This RAM transfers knowledge on each edges of the clock. thus the transfer rate of the info becomes doubles.

ROM : browse solely memory: Its non volatile memory, ie, the knowledge hold on in it, isn't lost albeit the facility offer burst. It’s used for the permanent storage of data. It conjointly posses random access property. data can't be written into a memory by the users/programmers. In different words the contents of ROMs square measure set by the manufactures.

The following sorts of ROMs Associate in Nursing listed below :

(i) promenade : It’s programmable memory. Its contents square measure set by the user. The user will store permanent programs, knowledge etc in an exceedingly promenade. the info is fed into it employing a promenade programs.

(ii) read-only memory : Associate in Nursing read-only memory is Associate in Nursing effaceable promenade. The hold on knowledge in EPROM’s are often erased by exposing it to ultraviolet|ultraviolet illumination|UV|actinic radiation|actinic ray} light for concerning twenty min. It’s challenging to erase it as a result of the read-only memory IC has got to be faraway from the pc and exposed to ultraviolet|ultraviolet illumination|UV|actinic radiation|actinic ray} light. the complete knowledge is erased and not hand-picked parts by the user. EPROM’s square measure low-cost and reliable.

(iii) EEPROM (Electrically effaceable PROM) : The chip are often erased & reprogrammed on the board simply computer memory unit by computer memory unit. It are often erased with in an exceedingly few milliseconds. there's a limit on the quantity of times the EEPROM’s are often reprogrammed, i.e.; sometimes around ten,000 times.

Flash Memory : Its Associate in Nursing electrically effaceable & programmable permanent kind memory. It uses one electronic transistor memory all leading to high packing density, low power consumption, lower price & higher dependability. Its utilized in all power, digital cameras, MP3 players etc.