Classifications of RAM

Classifications of RAM

RAM: It can access any memory Randomly, so its called RAM.

Memory can be divided into two topics:
1. Physical Memory – Physical memory consists of hardware components.
2. Logical Memory – Logical Memory relates to how memory is looked at and accessed by the CPU.

Physical Memory Module / Packaging:
1. DIPP - Easily distinguished from SIMMs or DIMMs. DIPP are usually mounted directly to system board via a series of prongs along each side of the microchip. This type of memory is no longer used to provide main system memory.
2. SIMM – Single-in-Line Memory module . SIMM are available in 30 pin & 72 pin forms. 30 pin SIMM’s are 8 – bit meaning it can transferred into or out of the module 8 bits at a time. 72 pins are 32 – bit. SIMM’s are older technology, they are typically used for fast-paged and EDORAM. You are not as likely to find a SIMM with SDRAM, since dual inline memory module (DIMMs) were the prevalent from when SDRAM was introduced.
3. DIMM –Duel Line Memory module. DIMM modules look similar to SIMMs but are slightly longer and are inserted into a different type of slot. DIMM have two rows of connectors, 168 connectors in all, and are 64 bits.
DIMMs are likely to contain either EDO RAM or SDRAM because those technologies were common when DIMMs were introduced.

Put on Dim Slot Singly. Its called SDRAM also. Now This kind of Ram is use Widely.
3. RIMM –Rambus Inline Memory module. RIMM is designed specially for use with RAMBUS memory.
RIMMs look just like DIMMs but have 184 connectors. They are also more proprietary and less common than SIMMs and DIMMs. RIMMs are 16 bit.
4. SoDIMM – Small Outline DIMM Memory. This kind of memory module frequently used in LAPTOP Computers.
The physical size is much smaller then DIMM. The most common pin configurations are 72 and 144 pin modules.
5. MicroDIMM – The MicroDIMM is a module designed primarily for subcompact and portable computers.
The MicroDIMM is half the size of an SoDIMM and allows for higher density of storage. The MicroDIMM module is not keyed but will only install property one way.

Memory Bank –
The bit width of a memory module is very important; the term refers to how much information the processor can access from or write to memory in a single cycle. A memory Bank represents the number of memory modules required to much the data bus width of the processor.

Calculating Memory Bank Size –
1. Determine the data bus width of the processor in your computer (16 bits for a 386SX, 32 bits for a 386DX or 486, 64 bits for the Pentium family).
2. Determine the bit width of the memory module (30 pin SIMMs are 8 bit, 72 pin SIMM are 32 bit, DIMMs are 64 bit, and RIMMs are 16 bit).
3. Divide the processor’s data bus width by the memroy’s bit wdth . The number you get is the number of memory modules you must install to create one full bank.

Logical Memory:
1. SRAM : Static Random Access Memory
2. DRAM: Dynamic Random Access Memory

1. SRAM: It’s the first type of RAM available. It’s the memory of Processor. It is more expensive and Faster than DRAM. It needs a continuing Power supply. It does not require regular updating and refreshing by the CPU. SRAM is typically used only for system cache. Made by Lache Circuit, which is very expensive, for this Circuit it doesn’t need to be Refresh.

Processor

L1: Internal Processing. L1 has to take help from L2 for processing.
L2: L1 & L2 cannot work alone. They are depend on each other. L2 works for Network Processing.
L3: Middle Cache Memory. Its Optional. It speed up the power of RAM..

2. DRAM: DRAM chips provide much slower access than SRAM chips but can store several megabytes of data on a single chip. Because of its low cost and high capacity, DRAM is used as main memory in the computer.

a. EDORAM: Extended Data out RAM improves on traditional DRAM by performing more than one task at a time. When one piece of data is being sent to the processor, another is being retrieved from the RAM module. While that piece of data is being transferred the EDO RAM is looking for the next piece to retrieve for the processor. EDO Ram chips can only in a computer system whose processor and motherboard support its use.
b. SDRAM: Synchronous dynamic RAM or SDRAM, is about twice as fast as EDO RAM because it is able to run at the speed of the system bus(up to 100 –133MHz).
c. RDRAM: Rambus Dynamic Ram gets its name from the company that developed it, Rambus Inc. RDRAM can be used only in computers with special RDRAM channels and slots. RDRAM is fairly new, so don’t expect to see it in computers that were manufactured before 1999.
d. DDR: Double-data rate Ram doubles the rate of speed at which standard SDRAM can process data. That means DDR is roughly twice as faster as standard RAM.

These RAM are of two types-
DDR1- 1 nouch
DDR2- 2 nouch

e. VRAM: Video Ram is a specialized type of memory that is used only with video adapters. The video adapter is one of the computer’s busiest components, so to keep up with video requirements, many adapters have an on-board micro-microprocessor and special video RAM. Faster version of Video memory have been introduced, including WRAM.
f. WRAM: Window Ram is another type of video RAM but it provide faster access than VRAM.