On 26 Sep 2000, at 9:51, [EMAIL PROTECTED] wrote:
> At 08:09 AM 9/26/00 +0000, you wrote:
> >I have to buy some 72 pin SIMMs.
> >
> >How can I recognice the difference between 1-bank type dram and 2-bank type
> >dram.
> >
> >To fill all my motherboard I need to use only 1-bank type.
> >
> >Thanks.
> >
> >__________________
> >Alejandro Lieber
>
> I am a bit confused about your question. My brain tells me that Dram is
> generally only found in 168 pin DIMMS and that the bank issue relates to
> your mother board. There are generally 2 banks or more of
> slots. Sometimes each slot is a bank, in the newer boards, and you can put
> your RAM sticks in mismatched, the largest stick in the first slot and
> decreasing. Sometimes there are 4 slots, two to a bank and you must pair
> your sticks, each bank must have two matching sticks. Some boards bank one
> and two, three and four, others bank one and three, two and four. I have
> found these often have no markings to indicate which and one must play
> trial and error, mixing it about until they work right.
> A lot of boards need to be fitted with the right parity or non-parity RAM
> also. often it is best to take the machine to the shop and test the RAM in
> it before buying, the shop can then look to see what you have, what you
> need, and play mix and match to find RAM that works correctly in your
> system. I find that even with second hand RAM he shop is generally willing
> to go to this trouble. As to what you describe above, I am sorry if I have
> gotten it mistaken and not addressed your circumstances.
> bye,,,,,,,,,,,,,,,(\
> Yolanda ,,,A+,,,,,,\\_/(\
> UIN 4898262,,,,,,,,,Q Q \)
> rockettalk 383426 =(_T_)=
> http://members.home.net/pippi5
> http://members.home.net/villasubrosa/garden
Dear folks,
Let's see if I can clear up a little confusion, here.
For 72-pin SIMMs, it's the motherboard that requires either one
SIMM or two SIMMs be added at a time. There are no special
SIMMs for this - "bank" is the term usually used for the minimum
set of memory that must be added at a time. This minimum set is
a function of the number of data bits the processor requests, and
the number of bits a single SIMM can supply. The number of bits
supplied must exactly match the number that the processor
requests. (For standard PC-designs, at least. For
embedded/special purpose designs may not be so.)
For motherboards from about the 286 era on, there are usually two
to four banks of memory. In earlier machines, the 30-pin SIMMs
needed to be added in sets of one, two or four, and 72-pin SIMMs
could be added in singles. With the advent of the 32-bit
processors, you needed to add 30-pin SIMMs in sets of four, 72-pin
SIMMs in sets of two, and 128-pin DIMMs in singles. This is
because 30-pin SIMMs output 8 bits at a time (9 with parity bits);
72-pin SIMMs put out 16 bits at a time (18 with parity bits); and
DIMMs put out 32 bits at a time (36 with parity bits).
64-bit wide processors, like the Compaq Alpha (and whatever Intel
finally calls theirs) have banks that are even larger, requiring double
the number of SIMMs be installed at once.
So, you must determine, from your motherboard manual, how
many SIMMs you must add at a time to fill a bank. You may only
fill a bank, or leave it empty, or the computer won't work. You
must also determine what speed of SIMMs you need, and if you
need parity SIMMs or not. "Parity" refers to extra bits used for
error detection - some motherboards use it, some don't.
Hope this helps,
Anthony J. Albert
Addenda to Pippi:
It's all DRAM - 30-pin, 72-pin, 128 pin, etc, it's all DRAM memory,
mounted in modules. SRAM (the other kind) is used for cache
memory, and is purchased either in separate DIP packages, or in
weird modules, for the very newest machines.
Of course, whay back when in the 8088 days, you bought DRAM in
DIP packages, too. :)
==============================================================
Anthony J. Albert [EMAIL PROTECTED]
Systems and Software Support Specialist Postmaster
Computer Services - University of Maine, Presque Isle
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