Memory - What's Involved

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Memory - What's Involved

System Memory

-Memory is widely discussed and can determine better performance in the PC system. Now most of you know of RAM this stands for (Random Access Memory). This memory is considered volatile, which comes down to being erased when the computer is turned off thus cutting power to the RAM. What are the types out there? There are two basic forms which spur into more types of memory used for video cards, motherboards and so on.

Basic Types and Operation

-Memory holds information that was derived from the hard drive. Data is stored using bits and is interpreted as a (0) or a (1). A (0) indicates a no voltage applied and a (1) indicates a charge. Charge what you ask? Well on a SIMM or DIMM modules (discussed in Formats) there are little black chips that contain millions of tiny transistors. These are used to store your information temporarily. Of course the information is refreshed often so to stay current. Not only is this type memory important but your system uses cache memory on the processor and on the motherboard for even faster access times. Take note that the RAM is what is also called volatile memory. This means when you turn that old computer off, all the information in those charged transistors is gone. Now we have a zero charge and no information.

-Most common types of memory you will run into is DRAM, and VRAM. The DRAM has different technologies attached to it such EDO (Extended Data Out), FPM (Fast Page Mode), BEDO (Burst Extended Data Out), and SDRAM (Synchronous Dynamic Random Access Memory). This sounds pretty confusing doesn't it? Just remember DRAM and this memory has technologies added to it. Example :

-EDO DRAM, this is a little faster than the FPM and is used in newer machines of today that do not exceed 75 Megahertz Bus speed.

-BEDO DRAM, This is EDO on steroids that allows pipeline of information. This also allows faster bus speeds and is a quick RAM. But the bad side is that it never really caught on with motherboard chipset support.

-FPM DRAM, This is also called Non-EDO RAM and is pretty universal with all systems that do now exceed 66 MHz bus speed. This type memory basically allows pages of 7 kilobytes that can be loaded and subsequent request can be made without delay making FPM fast.

-SDRAM, This type of RAM uses the same Bursting technique like the BEDO RAM and also enjoys running at the system clock speed of 100 MHz. Good Stuff !!

-The main stay of these today are SDRAM. Most likely this will become the next standard till something else comes along to wipe it out. Lets figure out what formats these type of memory come on.

-So far we know that RAM comes in SIMM and DIMM format. We know the types of RAM and now we know some more about error correcting otherwise known as Parity. This comes down to security for those who are worried about errors.

-RAM also over the years has had some neat tricks added to it. If you have a RAM chip that is doing a ga-zillion operations you might want to check it for error right? Naaa, but some do, this is done by using parity RAM or ECC RAM. So not to throw you off it would look something like this added to the rest of what you learned ECC EDO-SDRAM. Meaning, Error Correcting Code- Extended Data Out -Synchronous Dynamic Random Access Memory. Geezzz, get real huh!? Or just Parity RAM. Well there is also non-parity RAM which just means it doesn't have the extra chip to check for errors and is cheaper.

-This is how Parity RAM works for those interested. Using extra chips on the RAM allows it to keep track of bits. The ninth bit sent through would do a check sum to make sure all the other 8 bits matched up. If something shows up wrong the system will know it then. Now lets look at ECC Ram.

-ECC (error correcting Code), checks for errors and even can fix the wrong bit to the right value allowing the system to keep on trucking. ECC is probably the way to go but is a little more expensive. Actually both types of memory is real important if you run a server or applications that are real sensitive.

-Now lets look at formats of memory.

Formats

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