Thank you Markku; The cell arrangement of DRAM has been frustrating me for a long time now. Probably more because I set out to find an answer than because it was something I needed to know. The additional questions below simply sprung to mind as I was reading your response and are only secondary. On Wed, 2009-09-30 at 12:07 +0300, Markku Kolkka wrote: > William Case kirjoitti viestissään (lähetysaika keskiviikko, 30. > syyskuuta 2009): > > The second diagram shows a set of 4 X 4 arrays -- with a > > major disclaimer about its accuracy at the bottom. I have > > also seen other sites plus a couple of text books I own that > > show the cell arrangement as a linear setup. But only for 32 > > bit machines. I found nothing for 64 bit DRAM. > > The bit width of the CPU has no effect on the DRAM chip layout. I know. I only mentioned the CPU registers to avoid someone taking a lot of time explaining the difference between SRAM and DRAM. Perhaps mentioning latches only confused the issue. > > You simply connect enough chips in parallel to achieve the > desired data bus width. A typical 64-bit DIMM "stick" has eight > 8-bit wide chips. I'll take that information to the bank. To state it another way just to make sure I've got it. A typical physical address goes to, or points to, 8 + 8 + 8 + 8 + 8 + 8 + 8 + 8 cells arranged side-by-side in a line on an individual DIMM/DRAM stick. I suspect that by thinking of address as divided into bytes rather than a single 64 bit word (dword, qword, -- pick your author) there is a natural division for instructions, numbers and characters within the 'word'. Or, is there some physical reason why it is thought of as 8 + 8 ... When you say "chips" above I assume you mean cell, i.e. chip = cell = 1 capacitor and 1 transistor for storage of 1 bit. -- Regards Bill Fedora 11, Gnome 2.26.3 Evo.2.26.3, Emacs 23.1.1 -- fedora-list mailing list fedora-list@xxxxxxxxxx To unsubscribe: https://www.redhat.com/mailman/listinfo/fedora-list Guidelines: http://fedoraproject.org/wiki/Communicate/MailingListGuidelines
