New 4MB EMS RAM ISA Card Build & Test (Lo-Tech Origin)
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- Опубліковано 17 січ 2024
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In this video I build and test an amazing EMS RAM ISA card!
hkzlab - github.com/hkzlab/ISA_EMS_4Mb
Lo-Tech - www.lo-tech.co.uk/wiki/Lo-tec...
Chris Edwards Restoration - / @chrisedwardsrestoration
William - 3DOkid - wmgaming.co.uk/
Dermot Sweeney (Game Tech Refuge) - / @gametechrefuge
MsMadLemon - / @msmadlemon
CRG (Possible future build) - / @crg
ISA Card Using Raspberry Pi - • ISA Blaster: A softwar...
#retro #pc #electronics - Наука та технологія
A few mistakes in there - mentioning 8MB, when its 4MB lol, and at one point I said XMS, when I am talking about EMS. When looking at schematics, there's another demux or mux used to create the OE's for something else there. And I didn't focus on the RW signals - to determine direction of data (reads or writes). The issue with the A2286 - more clarification, I think it might be the ROM decoding taking E000 into account for the extended BIOS that IBM and some other manufacturers used. ie. Not just forcing a 16 bit read / write, but actually triggering BIOS selection perhaps. Since the A2286 does support EPROMs that are twice the size of what's fitted.
hkzlab - github.com/hkzlab/ISA_EMS_4Mb
Lo-Tech - www.lo-tech.co.uk/wiki/Lo-tech_2MB_EMS_Board
Chris Edwards Restoration - www.youtube.com/@ChrisEdwardsRestoration
William - 3DOkid - wmgaming.co.uk/
Dermot Sweeney (Game Tech Refuge) - www.youtube.com/@GameTechRefuge
MsMadLemon - www.youtube.com/@MsMadLemon
CRG (Possible future build) - www.youtube.com/@CRG
ISA Card Using Raspberry Pi - ua-cam.com/video/8HuxukpbsAE/v-deo.html
I have a 2 MB EMS Board in a Tandy 1000 TL, are you knowledgeable about Memory management on these systems?
Very thorough video......took me back to the IBM PCAT days.
Thanks Ian =D Hope you had a good Christmas?
When I need to write a raw image to a USB floppy, I use my Mac. Even my new M1 based iMac, no problem. Just using dd at the command line.
PSRAM would be the way to go here, but they are largely only available in BGA. I'm currently playing with a Stacy mainboard and developing a quick 4MB RAM replacement PCB using a PSRAM BGA which is just a couple of pounds.
Fancy doing one at some point ;)
@@GadgetUK164 I was thinking that, tbh… 😆 Once I’ve got the Stacy one working and know I can solder BGA’s (one of the reasons for trying it, also) I can adapt that existing schematic easy enough. Could put in a modern PAL as well to simplify it.
I know absolutely nothing about PC hardware and DOS configuration so you may as well have been speaking Greek, but I enjoyed listening to your Greek nontheless. :)
just put the board in a dish and use a toothbrush with the alcohol :D
Great! Iwould like to know if you can use two of them for having 8M on a 386? Also, is possibly to use it instead or with the onboard 30pin SIMMs?
I have a 386@40 with only 2M 30-pin SIMM RAM (4x512k). I would like to have it with 16M, Win 3.11, office, OrCAD, games, etc. But with its 2M is quite limited and 30-pin SIMM are quite rare and expensive and the old ones are sometimes unreliable.
I suspect 2 would not co-exist - ie. even if you put them at different base addresses, then used 2 copies of the driver - I am not sure 2 copies of the driver would co-exist properly. The memory provided by your 30 pin SIMM sockets will be "extended memory (XMS)" - certainly regards the memory above the 1MB A20 range, meaning that should co-exist with 4MB from this EMS card. You might want to see if your board supports 1MB or 4MB modules - you might be able to fit 4MB total or more in those SIMM sockets.
@@GadgetUK164 Well, I guess it would not be useful to have two EMS boards, I commented at the beginnig of the video and through the end it became clear yo me that one board would be enogh. As for the memory modules, 4M SIMMs should be supported on 386 boards and my board is a fairily new one; also the manual states that the max memory it supports is 32M, so 4Mx8. The trouble I have is that is hard to find 30 pin SIMM memory at a good price and in working condition. Where I live, most old computing tech is/was destroyed by the gold scrappers and what is to find is very priced because is "vintage" and on top of that is sold "untested". It means to pay a permium for something that possibly is broken.
About the driver, if put two boards, it might drive two of them with one instance of the driver? Maybe if you set them in contiguos space, as make one memory block, without holes from two boards? I had CDROM drivers that bevahe like that but also some that needed to be loaded once for each CDROM.
Would have been better in purple. Purple is better.
Haha, yes - it would actually!!! I don't think that was a standard colour I could pick, but it might be possible at extra cost....
Purple is the best colour
Still waiting for an ISA8 memory card that could offer EMS and 64kB of UMB on one card, so I wouldn't have to use two precious ISA slots just for memory cards. For majority of the retro soft, UMB has proven to be more beneficial than EMS, as it doesn't require any dedicated coding, just load all of the DOS drivers into UMB and the normal programs can use more RAM.
Yes, that would be very useful! I suspect this might be possible with a Raspberry Pi at some point!
@@GadgetUK164 You mean reuse ISA Blaster for it? I wonder how much work would that require. EDIT: nah, it wouldn't fly. ISA Blaster is based on Pi Pico which has only 256kB on board, wouldn't be enough even for the 4DOS swap which is 277336 bytes and can be kept in EMS, and where's the place for 64kB would have to be exposed as UMB... FURTHER EDIT: Ok, so it seems your idea has enabled me to find the card I need: PicoMEM, basically it's Pi Pico on ISA card with 8MB RAM connected through SPI (hey, but EMS is slow anyway, so should not make a difference). Things like EMS, UMB and ramdisk, even floppy emulation seem to be doable with this.
hey, wana sell only one PCB?
None left sorry! =/
You should be able to get an IBM Blue Lightning 75Mhz 386 (486SXLC/2 I believe) on that accelerator (due to the 25Mhz FSB) if it is an SX CPU, if it is a DX I would instead get a DLC/2 80Mhz (40Mhz FSB if you can configure it, otherwise it's not easy to upgrade) Also, and more or less important, get a 80387 on that thing as well or the equivalent 4x87SLC/DLC at the required FSB speed, AFAIK there are no clock doubled 387 variants be it SX or DX based. Still, it will help second reality if I am not mistaken, though the 75Mhz SXLC would be more than enough hehe
Also, get a ISA BUS expander, there are what are basically 16 Bit ISA Backplanes with a cable to connect to the motherboard BUS that give you additional slots (ISA supports this) and have their additional power input (using usually the same cable as HDDs or FDDs for some models, others have a legacy or ATX style motherboard power connector)
With this you could easily add an additional HDD controller as well as other ISA cards to make the x86 part of that miggy more capable.
I already have the chips waiting for that 386 =D