jalbert@cs.ubc.ca (Francois Jalbert) (01/05/90)
Hello everybody. I have been looking for a while without success for
the following:
4 Mb of extended-only memory starting at 1384 Kb in memory space.
So far, none of the dealers I talked to knows anything about such
boards. They looked into their books and found nothing appropriate.
If I can supply them with a maker and model number, they claim that
they could try to get one for me.
I justify briefly my need:
A) I want to use the board as a huge RAM disk on my 13.8 MHz AT-clone.
I know about caches, but I prefer a RAM disk with its content
optimized for any given application. Batch files will setup the RAM
disk for me.
B) The size of the files I use daily in a rotating fashion is such
that 2 Mb is a minimum. 4 Mb would give me plenty of breathing room.
I guess 1 Mb chips at 80 ns are good enough for a 9.3 MHz bus speed.
C) I have the usual 640/384 Kb split. I would rather avoid wasting that
384 Kb of extended memory I already have. It is also on the main board
and theoretically accessed faster. Good if the RAM disk directory is
kept there. However, I was disappointed when a RAM tester reported
several wait states on that extended memory. Especially since the
standard 640 Kb RAM has 1 wait state write, 0 wait state read. Any info
on this would be interesting.
D) I do not care about EMS and all that. I have no need for multitasking
and my applications do fine with 640 Kb and temporary files. I believe
a board without EMS capability is advantageous as it:
1) is simple, therefore more reliable. All you need is a bus driver
(LS244 or LS245?), a little bit of address decoding with some TTL'S,
and the memory sockets. If I had time, I think I could make one
up myself by looking at the circuitry of the memory board in my
old PC clone.
2) is probably cheaper.
3) is perhaps faster. I can't help suspect that all that EMS circuitry,
even when disabled, could add wait states. Anybody knows anything
about this?
E) The potential disadvantages are that:
1) EMS will never be available. That's all right with me as I won't
change my mind. I'll buy a 386 when I am satisfied with the
PS/2 software situation.
2) access to the extended memory is done by switching the processor
mode which I am told, is a slow process. I have no benchmark
results on this. A couple of magazines did mention EMS software-
driven to be the fastest option for fast 286's. That's not reason
enough for me to go the complex EMS way.
3) back-filling memory to 640 Kb is not possible. I already have 640 Kb
and I don't care for that option. I would care about back-filling
to 704 Kb though. That's the way I have been running my PC since 1984.
However, it won't recognize that memory. I wrote a device driver that
either does nothing, or modifies the amount of memory available in the
BIOS data area and then jumps at a specific address in the BIOS to
reboot the PC. Any info on this capability would be great.
I looked into magazines and found and old PC-Magazine (?) which had a
comparison of memory boards. I was surprised to see that the issues
discussed there were the ones I had been thinking about. Even the 384 Kb
jump was already an option available on some boards.
However, I doubt these memory boards are still available now. Technology
just goes too fast for such things to remain unchanged for 3 years.
The more recent magazines mention only fancy EMS 4.0 boards which don't
interest me. There has been some contradictory discussion lately about
the Everex RAM-3000. I was sorry to hear it is probably of the fancy breed.
In the past, the queries I submitted to the net have always been answered
satisfactorily. I remain amazed at the number of people who know exactly
what one is talking about, and the potential solutions. My recent queries
about EPIC in the TeX group were answered by the author!!! I have no doubt that
if such simple boards are still available, somebody out there reading this knows
about it. If I get no reply, I can safely just forget about the whole thing for
now.
Of course, if enough interest is expressed, I'll summarize.
Thanks in advance. Francois
'huilin@hpindda.HP.COM (Hui-Lin Lim) (01/06/90)
You might want to look at some of the AST memory products. I
have both the AST Advantage and the Rampage/286 which allow
memory to start on any 128Kb boundary eg. backfilled: 256, 384,
512; extended: 1024, 1152, 1280, 1408 etc. (I presume the last
value is the one you actually want 1024+384). These are NOT
AST's current offerings but I don't see why they should have
removed the capabilities from the current line of products.
Hope this helps
Hui-Lin Lim
ARPA: huilin%hpinddf@hplabs.hp.com
UUCP: {ucbvax,hplabs}!hpinddf!huilin
Phone: (408)447-2835poffen@molehill (Russ Poffenberger) (01/07/90)
In article <6169@ubc-cs.UUCP> jalbert@cs.ubc.ca (Francois Jalbert) writes: >Hello everybody. I have been looking for a while without success for >the following: > > 4 Mb of extended-only memory starting at 1384 Kb in memory space. > >So far, none of the dealers I talked to knows anything about such >boards. They looked into their books and found nothing appropriate. >If I can supply them with a maker and model number, they claim that >they could try to get one for me. > [LOTS of stuff deleted] You will probably do OK with a memory board that supports both EMS and extended memory. (Most boards do these days.) Anything like an Everex RAM-3000 or Intel Aboveboard/AT would do. These boards allow flexible starting addresses, BOTH extended AND expanded memory including mixing of both at the same time or the obvious case of either ALL extended or ALL expanded, just configure it to ALL extended. Note that I had difficulty with a RAM-3000 being incompatible with my AT clone, it seems it may not support faster bus speeds. The Intel Aboveboard/AT is a good buy even though it's configuration options were a little less flexible the RAM-3000. Prices on these can be had for ~$140 (0K installed) and can support up to 6-8Mb with piggyback cards (~$60). Russ Poffenberger DOMAIN: poffen@sj.ate.slb.com Schlumberger Technologies UUCP: {uunet,decwrl,amdahl}!sjsca4!poffen 1601 Technology Drive CIS: 72401,276 San Jose, Ca. 95110 (408)437-5254
vera@cadence.com (Vera VallentinPrice) (01/20/90)
In article <6169@ubc-cs.UUCP> jalbert@cs.ubc.ca (Francois Jalbert) writes: >Hello everybody. I have been looking for a while without success for >the following: > 4 Mb of extended-only memory starting at 1384 Kb in memory space. >A) I want to use the board as a huge RAM disk on my 13.8 MHz AT-clone. ...some stuff deleted here... >D) I do not care about EMS and all that. I have no need for multitasking > and my applications do fine with 640 Kb and temporary files. I believe > a board without EMS capability is advantageous as it: ...stuff deleted here... >However, I doubt these memory boards are still available now. Technology >just goes too fast for such things to remain unchanged for 3 years. ...stuff deleted here... >the Everex RAM-3000. I was sorry to hear it is probably of the fancy breed. The Everex RAM-3000 can be configured as either, extended, expanded or a mix of both on the card. The cost is $89 at Fry's right now, you may get better prices via mail order. Even if you never consider using expanded memory, some applications make use of it and improve in performance (such as Ventura Publisher and other larger applications). But then, you may not have a need to run them. I used such a card for a while and was very impressed about how easy it was to setup and configure, no troubles whatsoever. I was sorry to give it back (it was borrowed). Tall Tree Systems used to make such simple boards about 1986-87. Fry's Electronics in Sunnyvale is closing them out currently (really good prices). The boards are called JRAM, JRAM-PC, JRAM-AT etc. The manual said that the Ram is configured as extended memory, and that you can backfill the base memory. They are only holding 2Megs at a time, but you could use more than one board if you have enough slots left open in your machine. They also have Tall Tree's JRAM-JLASER combination boards for providing memory to laserprinters with insufficient memory. There are two hangups about this: Tall Tree's phone number is no longer valid. A person from Fry's said they might have changed their name (anybody on the net knows what happened to Tall Tree Systems?). And second, the boards were made for 640K motherboards. I found several mention in the manuals of the different models that JRAM may not work with a 1Meg motherboard (leave alone the newer 4 and 8 Meg MBs). However, I was able to configure the switches on the JLASER board I bought to read the 2Megs of RAM on my motherboard and use the 2Megs on the JLASER card. It was tricky and time consuming to switch all possible variations (they are not documented beyond 640K in most of the manuals). But to me it was worth it considering that the Laserprinter memory upgrade would have cost me some 2,000 Dollars for my Laserjet Plus. Be aware of those potential troubles. Fry's was good to let me try out three different models until I found the right one I could configure for my hardware. Considering you would be willing to build your own circuitry this may not bother you at all. Good luck! Vera. Disclaimer: I have no connections to Fry's other than being one of their customers. --------------------------------------------------------------------------- Vera Vallentin-Price Cadence Design Systems vera@cadence.com 408-954-7605 555 River Oaks Parkway San Jose, CA 95134 :-) ---------------------------------------------------------------------------
mvolo@uncecs.edu (Michael R. Volow) (01/20/90)
My most recent numbers for Tall Tree Systems is 415 493 1980 (sales) and 415 414 8324 (tech support). M Volow, VA Medical Center, Durham, NC 27705 mvolo@ecsvax.UUCP 919 286 0411