A couple of DRAM memory stick questions ??

[William Case]

Thanks poc;

Then it gets confusing again!

On Wed, 2009-09-30 at 10:53 -0430, Patrick O'Callaghan wrote:
> On Wed, 2009-09-30 at 10:55 -0400, William Case wrote:

> 
> It's the data that's stored in units of 8 bits. When addresses are
> stored then of course the same applies. When they're on the address
> lines of the memory bus, they may be in groups of 16 or 32 or 64
> (depends on the bus design). None of this matters to you as a
> programmer.
> 
Understood -- I think.  Put another way, on a 64 bit machine if the
memory bus is 32 lines wide the data, or whatever, would flow with the
first 32 bits immediately followed by the second 32 bits -- right?

(I am trying to avoid discussing whether data flows on the rising edge
or falling edge of a clock tick etc.)

> Note that the pedantic name for a group of 8 bits is "octet". A "byte"
> is the number of bits required to represent a character in some
> encoding. 
> 
> > When you say "chips" above I assume you mean cell, i.e. chip = cell =
> > 1 capacitor and 1 transistor for storage of 1 bit.
> 
> A chip has a whole bunch of cells (in the millions these days). They
> aren't the same.

Then what was Markku referring to when he said "A typical 64-bit DIMM
"stick" has eight 8-bit wide chips."  The chip is one of the minute
black chips I can just barely see on a RAM stick --?  That is what I
originally thought.

Markku's statement then implies that a 64 bit qword is stored in an 8 x
8 array of cells.  True?


By the Way:
The definition of a 'word' seems to be all over the place.

With Intel, the definition I have read says a 'word' is 16 bits, a
'double word (dword)' is 32 bits, and a 'quadruple word (qword)' is 64
bits.

The specs for the 64 bit AMD CPU I used to have defined a 'word' as
whatever the machine said it was.  In my case at the time, a 'word'
would have been 64 bits.  ????

I raised the question of 'words' with my local Linux Users Group and
simply got caught in a long debate amongst them with huge digressions
that resolved nothing to my satisfaction.

-- 
Regards Bill
Fedora 11, Gnome 2.26.3
Evo.2.26.3, Emacs 23.1.1