Date: Wed, 29 Oct 2003 10:06:05 -0800 From: PhotoEngineering <[EMAIL PROTECTED]> Subject: Re: [LIB] Amount of memory addressable??
At 06:10 PM 10/28/2003, you wrote:
Date: Tue, 28 Oct 2003 21:45:36 -0500 From: "Lewin A.R.W. Edwards" <[EMAIL PROTECTED]> Subject: Re: [LIB] Amount of memory addressable??
I am upgrading the memory in my Libretto and am a little bugged. According to the specs the maximum it can address is 64 meg however it has a 64 bit data width which means it can go over 4 gigs.
Actually--sorry--I miswrote. It has a 32 bit address buss which Toshiba did not use all of. If they had we could use 168 pin sodimms to upgrade the memory. As it is we are stuck to 144 pin.
No, it can't. The 64-bits is the data path width. Think of it as a road. The 64 bits is a measure of the width. The LENGTH of the road is controlled by the address bus width, and other factors, which limit it to 64Mb.
Actually it is not limited at all since computer memory has not been dependent on the width of the address buss since what?!? never? The idea that it is hype from people in an industry trying to keep suckers buying new equipment and keep themselves underworked and overpaid for doing nothing.
each does and which is needed for SDRAM? I am going to replace the EDO ram in my 110CT with SDRAM and am curious as to what the differances
No you're not. The L1xx does not have an SDRAM controller, it has a DRAM controller compatible with EDO-mode DRAMs. Also, in order to change anything at all you'll have to hack an existing L1xx module, because it is proprietary in shape. There is no SDRAM pin-compatible with EDO, mainly because there would be no point; the two memory types are accessed quite differently.
Heh--it has a programmable GA setup as a edo dram controller. It is never a problem to access a differant type of ram as long as the new ram works fast enough and we already know sdram ram does. It fact it is almost exactly the same as edo in that when a flipflop is latched it stays latched as long as power is applied to the chip!!:-) Why would I need to hack a Libretto module? The pinout of the expansion connector is same as a 144 edo sodimm. No hacking needed. I thought of a sodimm first but EDO is so expensive even used that it seems worthless to stick with it.
23 CAS0; 001 O
Column Address Strobe lines, 0-7. Loads a column address off the MAxx pins when asserted.
29 MA00B; 101 O 31 MA01B; 101 O> 110 MA00C; 101 O > 112 MA01C; 101 O
Unclear what those are.
They are address lines used in the first 4 bits of the colume address.
32 MA04; 111 O
Multiplexed row/column address bus, 0-12.
66 WED; 001 O 67 WEC; 001 O
Would appear to be two separate write enable strobes for two banks of x32 RAM (don't get excited, these are the two banks on the card).
The first is the write enable the second is the clock.
69 RAS2; 001 O 71 RAS3; 001 O
Row Address Strobe lines. Loads a row address off the MAx pins when asserted.
Since there are 12 address bits, each row and column can be at most 2^12 = 4096 cells. Maximally configured, that would mean 4096 x 4096 = 16M cells. * 4 byte lanes = 64Mbytes (external RAM). So I guess 64Mb + 32Mb is theoretically possible, if you can find 4Kx4K (16Mbx16) EDO-DRAMs in the right package
There is no limit to the memory the bios can see.
The BIOS would need to know about higher density RAM in order for this to work though. And presumably it doesn't, otherwise someone would be making third-party expanders for the L1xx.
It already knows about high density ram since it comes with it onboard.
Why would anyone build anything for a discontinued computer? Number one-- its very expensive to make a memory board. Number 2-- edo is extremely, extremely expensive. The cost for 256MB is way too much. SDRAM is much cheaper. 3 who's going to pay 1000 dollars for a memory modual for a libretto when a person could buy a new computer for that amount? Especially when 1 gig of sdram goes for about a hundred bucks.
John [EMAIL PROTECTED]
-- -- Lewin A.R.W. Edwards (http://www.larwe.com/) Learn how to develop high-end embedded systems on a budget! http://www.amazon.com/exec/obidos/ASIN/0750676094/zws-20
************************************************************** http://libretto.basiclink.com - Libretto mailing list http://www.silverace.com/libretto/ - Archives
-------TO UNSUBSCRIBE------- Reply to any of the list messages. The reply mail should be addressed to: [EMAIL PROTECTED] - Then replace any text on the message's subject line: cmd:unsubscribe --------TO UNSUBSCRIBE DIGEST------ Do above but with this on subject line: cmd:unsubscribe digest **************************************************************
************************************************************** http://libretto.basiclink.com - Libretto mailing list http://www.silverace.com/libretto/ - Archives
-------TO UNSUBSCRIBE-------
Reply to any of the list messages. The reply mail should be
addressed to: [EMAIL PROTECTED] - Then replace any text
on the message's subject line: cmd:unsubscribe
--------TO UNSUBSCRIBE DIGEST------
Do above but with this on subject line: cmd:unsubscribe digest
**************************************************************