Memory types or memory slots in simple terms

[NACERT]

Memory:
SIMMs , DIMMs, RIMMs, SDRAM, SO-DIMMs, MicroDIMMS, RAM, ROM, Dual-channel, single-channel, DDR, DDR2 /3.
I can memorise all these acronyms and definition about the above and answer any exam question that have seen so far, but I still don’t know what they are.
Is there any physical aspect (Size, shape, weight, color) that determines which type of memory module (or memory slot) each of them is?

By looking at each can you tell if it is RAM or DDR, ROM or SIMM, RAM or SDRAM, Dual-inline or Dual-channel ? (this question should show my confusion)
Where the difference is nothing to do with physical shape, appearance or else. Can please advise what determines, for instance if the memory is ROM or RAM.
I think this would help me clarify the definitions of different memories that I had to learn by heart without being able to understand.
Your help would be greatly appreciated.
Thank you in advance.

[wonkanoby]

for instance if the memory is ROM or RAM

rom is read only memory

thats used in devices to keep permenant data

its data is retained like a usb memmory stick after power of

only rom type in a pc would be the bios chip

as to the rest yes they are all different as regards the pin slots and cut outs to

match the memmory slot

[bk94si]

you don't really have to know. All you need to know is what kind to put in your particular model of computer.

[djotter]

SIMM = Obsolete
RIMM = RAMBUS = Obsolete
SDRAM = Precursor to DDR/2/3
microDIMM - Obsolete
ROM = Read Only Memory, only used in pre-programmed chips.

So the only two you really have to care about is -
SO-DIMM = Laptop RAM, slots are shorter than standard
DDR/2/3 = regular desktop computer RAM - http://en.wikipedia.org/wiki/File:De...Comparison.svg

If you have a particular question to what type of RAM/ROM to use for a particular situation, please ask. The more specific your question, the easier it will be to answer.

[Poci]

for instance if the memory is ROM or RAM

rom is read only memory

thats used in devices to keep permenant data

its data is retained like a usb memmory stick after power of

only rom type in a pc would be the bios chip

as to the rest yes they are all different as regards the pin slots and cut outs to

match the memmory slot

Actually the bios chip on your mobo is an EPROM which stands for erasable programmable ROM. Which means it "can" be written too, hence the ability to do a bios flash.