asplund@alcor.usc.edu (Daryl) (02/07/90)
Hello all, I have a Compaq '386/16 and have some questions regarding the design and architecture of the 32-bit memory and how it interacts with 16-bit memory. My questions arise because I have completely filled the 32-bit 2 Megabyte memory board. It seems as though my options are limited in respect on how to add more memory to my system. Now the questions: 1. I was told that if I added a 16-bit memory expansion card (using a slot) that the memory would not be linked contiguously with the current 2Mb that is on the 32-bit board; thus not allowing me to use one memory manager/driver to access all the extended/expanded memory. The reason given for this is that 32-bit memory works completely differently that 16-bit, therefore it would not all be seen as one "chunk" of memory. IS THIS CORRECT? 2. As the Compaq 32-bit expansion card (connects to the current 32-bit card) is about $700.00, does anyone know of any other makers of expansion cards that connect DIRECTLY to the Compaq supplied 32-bit memory card? I have heard that Kingston (a company in California) makes such a product. Has anyone had experience with this company / product? Is it reliable? 3. If I could get a 16-bit card to work (i.e. all memory accessible contiguousness), would I have to use static column ram as is on the 32-bit card? Or would I be safe using DRAM, since the access speed is 16-bit as opposed to 32-bit? Thanks in advance for the time and effort to answer my questions. Responses to any, all (or combination there of), are welcomed and appreciated. Please send ALL responses directly to me at: asplund@alcor.usc.edu
alien@cpoint.UUCP (Alien Wells) (02/07/90)
In article <7934@chaph.usc.edu> asplund@alcor.usc.edu (Daryl) writes: %1. I was told that if I added a 16-bit memory expansion card %(using a slot) that the memory would not be linked contiguously %with the current 2Mb that is on the 32-bit board; thus not %allowing me to use one memory manager/driver to access all the %extended/expanded memory. The reason given for this is that 32-bit %memory works completely differently that 16-bit, therefore it %would not all be seen as one "chunk" of memory. IS THIS CORRECT? This seems to be total nonsense. What may be happening is that the Compaq memory board address decoder may be intercepting more addresses than it is using (in case you are using larger simms or a daughter card), but the 386 chip has an on-board MMU that can remap your memory any way you want (and there are lots of available products that use can use to take advantage of this). %2. As the Compaq 32-bit expansion card (connects to the current %32-bit card) is about $700.00, does anyone know of any other %makers of expansion cards that connect DIRECTLY to the Compaq %supplied 32-bit memory card? This is the real cost of private memory busses. You do get increased performance, but the price is incompatibility with any standard. You aren't even guaranteed to be able to use expansion cards from other Compaq models. Compaq is big enough that there may well be compatible board manufacturers, but I don't know anything about them. >3. If I could get a 16-bit card to work (i.e. all memory >accessible contiguousness), would I have to use static column ram >as is on the 32-bit card? Or would I be safe using DRAM, since >the access speed is 16-bit as opposed to 32-bit? Each board will have its own memory requirements that are independant of any other board (unless one is a daughter board, or they share controlling circuitry on the mother board, neither of which is true on a memory board on the bus). The board you buy will determine what chips you need. Given the slower bus access time and the 16 bit path, static column DRAMS are unlikely ... -- --------| I don't get my eyebrows trimmed, only styled. Alien | - a Clearpoint VP --------| jjmhome!cpoint!alien bu-cs!mirror!frog!cpoint!alien
marshall@wind55.seri.gov (Marshall L. Buhl) (02/08/90)
alien@cpoint.UUCP (Alien Wells) writes: >In article <7934@chaph.usc.edu> asplund@alcor.usc.edu (Daryl) writes: >%2. As the Compaq 32-bit expansion card (connects to the current >%32-bit card) is about $700.00, does anyone know of any other >%makers of expansion cards that connect DIRECTLY to the Compaq >%supplied 32-bit memory card? Have I got good news for you. Last fall I decided to upgrade the RAM on our Compaq 386/16,20,25 machines. I found GREAT prices on clone Compaq RAM. I found the 4 MB modules for the 20 and 25s so cheap, that's all I bought. My local Compaq dealer sold me 5 4MB modules for $730 each. They beat out Sigma Data by $4. A few weeks after I ordered them, Sigma Data called and said the price was now $600. That's for 4 megs folks. I could have saved myself $1000 by waiting. Those greedy bastards at Compaq wanted $1845 each. What balls. I've have the RAM in for almost a month and have had no problems. I also bought RAM chip sets for the 16 MHz systems. I got them from Cal-Abco for $126 per meg (36 chips). You can also get clone daughter cards for the 16 MHz systems too. Look in the back of PC Week or InfoWorld for chip dealers. Of course, I could have gotten them from Compaq on GSA discount for a mere $482 per meg. What a nice outfit they are for ripping off the government by charging 4 times the street price for RAM. The clone dealers offer significant quantity discounts if you're buying for several systems. Check them out. BTW, just because a mail order firm doesn't list your chip in the ad doesn't mean they don't carry it. Happy upgrading... Marshall -- Marshall L. Buhl, Jr. EMAIL: marshall@wind55.seri.gov Senior Computer Engineer VOICE: (303)231-1014 Wind Research Branch 1617 Cole Blvd., Golden, CO 80401-3393 Solar Energy Research Institute Solar - safe energy for a healthy future