Building a modern computer compatible with older hardware - Page 1
Forum section: electronics / general

author: Bendba
author_rank: Regular Contributor
timestamp: July 01, 2018, 06:30:11 am
content: Hi,Here is another one of my crazy ideas. I am wandering if there is something out there that would let me build a modern computer, capable of running AutoCAD and handle a 2560*1080 144Hz screen (well, at least have a graphic card slot that will allow for a card able to handle it) but yet handle the following:- IDE, SCSI and SATA drives- 3.5" and 5.25" floppy drives- ISA and PCI slots at least 4 of each free after using slots for SCSI, Floppy drives and other adaptersMy biggest struggle is to find a motherboard with so many ports and slots. Finding a case to fit it in is a little bit of an issue too but that, I can make myself if needed.Any advices?

author: Ampera
author_rank: Super Contributor
timestamp: July 01, 2018, 06:38:00 am
content: The question is why. While a stupid question, it's not an ignorable one.You could no doubt get 1 and 2, and maybe even 3, but a 2560x1080 144Hz screen will not belong on a system that will be a Pentium 3 at about the fastest.My suggestion is to deck out a nice Pentium Pro machine (if you want plans or ideas, hit me up in DMs, I can show you what I made) and then in a good custom case, stick a modern computer in there, and then just integrate a KVM into the case.I personally like to keep my machines separate, and while there are some special case things you can do (like using USB ISA slots, and getting PCI SCSI/PATA cards) however the more you try to shove into the system, the more it will cost, and the less compatible it will be with programs.If the desire is to just be able to play a few games off hand, DOSBox and VMs are ever present, and if you really want a real legacy PC compatible, there's nothing like a period accurate all in one machine.

author: Bendba
author_rank: Regular Contributor
timestamp: July 01, 2018, 06:40:01 am
content: Hi,Thanks for your answer. I would like to have four or five different machines from different eras. But I am leaving space in the house.

author: Ampera
author_rank: Super Contributor
timestamp: July 01, 2018, 06:45:13 am
content: I honestly have never really had space issues, as ATX towers don't really take up much space. 3 of my main legacy machines only take up about 5/8ths of the space under a small camping table I have them set up under (as I am too poor for real desks).

author: Bendba
author_rank: Regular Contributor
timestamp: July 01, 2018, 06:50:50 am
content: Well, at the moment, anything electronic that I do is either on the dining table or lounge room floor.

author: Kleinstein
author_rank: Super Contributor
timestamp: July 01, 2018, 07:18:26 am
content: One would not find a MB to fit all that. It is already difficult to get a board to support several ISA and PCI slots - usually it was only 1 or 2 of the old ones. The modern graphics cards for a high resolution monitor come in PCI express and there are no boards to combine modern PCI express and antique ISA slots - they are just too far apart in time.So it would likely need at least 2 computers. One modern one and 1 old box to support ISA / PCI and similar. The old one would be likely something like Pentium MMX to maybe P3. One might still be lucky to find such an old box.So it would be more like 2 computers - though a few spare parts for the old one might help.

author: Ampera
author_rank: Super Contributor
timestamp: July 01, 2018, 07:21:02 am
content: I mean they do sell PCI graphics cards that could handle that resolution, no doubt about it, I'm just saying, cost wise, it wouldn't make sense.

author: Halcyon
author_rank: Unknown
timestamp: July 01, 2018, 09:30:59 am
content: StarTech make a bunch of modern controller cards for IDE and SCSI drives:https://www.startech.com/Cards-Adapters/HDD-Controllers/As for floppy drives, the modern OS's still support them. You can buy USB floppy disk drives or if you wanted an interface, I'm sure you can find a card that'll do that too. I use the Kryoflux for reading/writing old disks in all kinds of weird and wacky formats.If all you want to do is to be able to read and write to old disks, that can be easily and reletively cheaply done on a modern machine.

author: exit_failure
author_rank: Regular Contributor
timestamp: July 01, 2018, 09:11:43 pm
content: One thing that would be important to know is, what operating system(s) are you planning to run on that System? Depending on that driver availability might be one of your biggest problems. There are USB and/or PCIe adapters for every interface you mentioned, even ISA. Depending on your use case that is the solution I would prefer since you could use almost any platform from the last ten years or so for your machine.

author: Ampera
author_rank: Super Contributor
timestamp: July 01, 2018, 11:50:19 pm
content: If you have your heart set on this, here are my two suggestions:If you really intend to use this as a daily driver, get your modern system of choice. Something like Z97, or AM3+, as that's what will usually have some PCI. Get PCI (PCIe is even better) interfaces for what you want (IDE/SCSI) or even get something like AM2/AM2+ which will usually have IDE and SATA on board, as well as some more PCI slots.Get some USB ISA slots. I'd not go nuts, as to make this truly useful, you won't be benefiting much from these. For graphics, get a GTX 7800 512MB, as these are dirt cheap (last I checked, I got two for 20 bucks a pop), and will be still able to do high resolution work. You will be dual booting your modern operating system of choice (Linux will actually not be a bad idea here, as you might even get drivers for some older cards, and things like USB ISA slots) and Windows 2000. Windows 2000 will very likely support much of your older ISA hardware, with USB ISA slots, but will still be able to hold up with some newer tech, like the 7800.The other idea is to get the biggest, baddest Slot 1 configuration you can get. If you can find Socket 370 or Socket A boards with half PCI, half ISA, even better. Something like an SE440BX-2 will be perfect for you, as they are dirt dirt cheap. Get the fastest Slot 1 card you can find/afford, and stick it on in. You will now be getting two graphics cards. Get the fastest thing on PCI you can get, something from nVidia, as a few manufacturers made some semi-competent PCI graphics cards. Then, get an AGP card of your choice. GeForce 2MX isn't a bad choice here, it's what I have in my P3-450 machine, and it could afford to be in really any Slot 1 machine. If you want, you could in theory get an end of the line AGP card, but you might have some issues with link speeds, I don't know.For an OS, you will be using 98SE, and ArchLinux x86 (or your choice of a barebones i686 Linux distro). Modern Windows will not work or be practical here, so you will have to rely on Linux to do your CAD work, if you can find a usable alternative to AutoCAD on it (who know, maybe it works on Wine, maybe there's even a Linux version). You won't be doing ANYTHING fancy here, as even a 1Ghz Pentium 3 won't be powering you hard, especially at high resolutions. Regardless, you should still be able to do some CAD work here, while having a machine that is right in the perfect position for much of the early Windows, late MS-DOS library. If you can get a Voodoo 3/4/5, that will make it even better, as you will have Glide support.Neither of these are good options, and you will ALWAYS be making compromises, expensive purchases, and honestly a whole load of decisions that could easily be solved by just having two computers. Even getting something like an ATX super tower that can fit two motherboards (One full size, one mini-ITX) would work better here.If you want to save space, I suggest to plot exactly where you want to be playing legacy PC games. If you are into earlier DOS stuff, a low power 386 or high power 286 will be your friend. Later DOS stuff is done well by anything from a 486 to a Pentium 3. Early Windows titles are good on anything from a 486 to a P3, with only later stuff like Half-Life needing Pentium 2/3 power.I'd suggest a Pentium Pro machine, as they are very capable on most mid-late non-CPU locked DOS games, but can hold up to a LOT of 1998-2000 stresses, like Half-Life and Unreal, especially if you get something like a Voodoo 2, or comparable. Either way, I will leave the specifics to you. If you need help, I have some good experience making and building older PCs with the intent of having nice legacy rigs, so shoot me a PM, I can help you out.

author: amyk
author_rank: Super Contributor
timestamp: July 02, 2018, 03:35:46 am
content: https://www.iwavesystems.com/pcie-isa-bridge.htmlApparently such a thing exists, although from a quick search I haven't found any actual purchasable PCI/e to ISA bridge hardware.

author: AG6QR
author_rank: Frequent Contributor
timestamp: July 02, 2018, 04:14:25 am
content: Are you wanting to run the current version of AutoCAD? That means you must use Windows 7 or newer.Depending on your reasons for wanting to do this, I'd seriously consider acquiring two (or more) computers, and networking them. Get a nice new fast modern system, with lots of good fast disk space, and the nice video hardware. Put the newest version of Windows on it, and run AutoCAD on this computer. In addition, get something that will handle the antique hardware, and put a reasonably fast ethernet card in it. You can put Linux on the antique box, and share the drives over samba. Or you can use an appropriate version of Windows if you prefer. If the two computers are plugged into the same network switch, the networking latency won't be too bad. This will give you access to all the old data and old disk formats from a modern computer.Apologies if I'm missing some crucial constraint that makes this solution impossible.

author: exit_failure
author_rank: Regular Contributor
timestamp: July 02, 2018, 06:43:58 am
content: Quote from: TwoOfFive on July 01, 2018, 11:50:19 pmUnfortunately, that's not a very good idea. This is a 13 year old Graphics card. I know that you chose this because of compatibility with older operating systems but there are multiple reasons why this card is about the worst thing he could get for his system:The oldest Windows supported is Windows XP. WIndows 2000, ME, 98 or 95 or even older are all unsupported. If the card even runs with those systems you at least won't have any 2D/3D acceleration. Judging on the hardware you plan on supporting this might become a problem.The newest Windows supported is Windows 7. Windows 7 will go out of support in January of 2020. That means in 18 Months you will have no Windows OS that still receives security updates that also supports your graphics card. This also often means that programs, like AutoCAD, will drop support for those older operating systems shortly after that.Those cards won't fully support your monitor. To get 2560*1080@144Hz you'll need at least HDMI 2.0 or DisplayPort 1.2 connectors. Both didn't even exist when that card came out.This card is the absolute minimum you would need the use AutoCad properly. While it might run, it will frustrate you very quickly.My recommendation, as mentioned above, would be getting a modern, up to date PC and using USB/PCIe adapters. For support of older operating systems, use virtual machines. For everything you can't run with this kind of setup, get the appropriate old hardware. That should be the easiest and probably even the cheapest approach to your problem.

author: Ampera
author_rank: Super Contributor
timestamp: July 02, 2018, 07:04:09 am
content: I gave the best off the cuff guidelines I could.1. I swore the 7800 had Windows 2000 support, (and after looking for them on nVidia's website, there do appear to be 7 series drivers for Windows 2000). This makes sense because the 7 series cards came out in 2005, only 6 years after the release of Windows 2000, an operating that was still in fairly heavy use at the time by power users. You would definitely have 2D/3D acceleration here.2. A. So? He has it for a year and a half. I mean you're going to be throwing security updates out the window anyways with this machine, if it is to be built. I still run some XP boxes on the internet, and so long as you stick to google and a couple occasional safe sites, nothing really can go too wrong, especially behind a firewall. Even if security is still an issue, Linux comes to our rescue as always, which is why I suggested it for my second idea build. Graphics drivers seem to never really go out of style like on Windows, with Linux having support for even some old yellers, with I think XWS support for even some older VLB and ISA video cards. Another idea is to just use integrated or a cheaper, modern graphics card, like how I suggested in my second idea build.3. It wouldn't run his display at the refresh rate (why you would need 144hz for AutoCAD I don't know), but dual link DVI /should/ be able to power that display at 60hz.4. That's the name of the game.The best idea is two computers. Your retro machine of your choice, and your modern machine of your choice. For the price you would even SPEND on USB to ISA adapters to start with, all amounts of worth while leave.

author: KubaSO
author_rank: Contributor
timestamp: January 08, 2021, 08:17:58 am
content: Looks to me like you want a PDP-11 running on an FPGA, with monochrome bitmapped screen output (so that it doesn't take too much memory), probably the LSI-11 instruction set with floating point dumped in, no need for MMU at first. You can run RT11 on that. Then you can implement some of AutoCAD 1 from scratch, and there you go: modern, display as you wish for, very compatible with old stuff - you could have QBUS on that thing just for bragging rights, although not to slow things down too much you'd want that slow bus to run on core #2.You'd also get the bragging rights for having the first integrated SMP LSI-11. PDP-11s could have their QBUSes or UNIBUSes joined via CPU-to-CPU links, but that was NUMA at best: two (or more - number of slots in the card cage was the only limit) separate computers with a small shared address space window to "talk" to each other. SMP would be news. Given an FPGA that can push HDMI at the resolution you wish, and the push for modernity, you could probably splurge for a $1k FPGA board to do that. A rather modern system emerges, with 32 cores running at a very respectable clip. If you wanted to go fancy, you could add the PDP-11 "standard" MMU, and tweak it a bit to remain legacy-compatible but make it support SMP.Since a proper PDP-11 core should be microprogrammed, you can surely expand the architecture a bit with some SIMD and cryptographic primitive execution units (AES!), and of course throw in h.264 decoder and encoder, and expose them through the microcode (new opcodes!). You're well on your way to have seamless support for video decoding at that point, and could write your own youtube client in stunning dithered monochrome. Don't forget colorspace conversion operations that do monochrome dithering!Systems like this were sufficiently "big" that you'd want a small "microcontroller" to control boot process. For that, I'd suggest a physical T-11 (an "8085-like" tiny PDP-11 in a single 40-pin DIP, with one operating mode basically exposing an 8085 8-bit bus) - you can get them on eBay. It should read the FPGA bitstream off a serial EEPROM, bit-banged, but when the EEPROM is empty it should fetch the bitstream from paper tape, obviously. You definitely want that T-11 to be joined to a QBUS slot or two, since it'd be absolute travesty not to interface that tape reader using period-appropriate interface board. Bootstrapping that T-11 should be ceremoniously done at least from a modern front panel alternative: a vandal-proof ATM keypad (those aren't expensive). I mean, in case you were a vandal, you wouldn't want anything to happen to the machine during the one glorious literally digital IPL.Once bootstrapped you can write the bootloader to the smallest parallel interface FRAM you can find, interfaced by 74 LSI logic and proper bus transceivers to QBUS - a proper QBUS card can have some air on it, I mean, unused spaceOr just have a PROM QBUS card with the bootloader patched in with a bunch of diodes - the once-in-a-lifetime IPL would be definitely to check out the bootloader before soldering in the diodes, right?As far as making old and new compatible, I can't imagine being in a better place

author: macboy
author_rank: Super Contributor
timestamp: January 08, 2021, 04:33:05 pm
content: Quote from: Bendba on July 01, 2018, 06:30:11 amImmediately you have an issue. At least 4 PCI and 4 ISA slots "free" plus a graphics card means minimum 9 slots, but probably 11+ since you will need a SCSI card and a SATA card. ATX supports 7 slots. I don't know what kind of case you will find for a dozen slots.One of or maybethemost modern chipset supporting true ISA is Intel 845G for Pentium 4. Anything later (for Core CPUs) will be using a PCI to ISA bridge with dodgy compatibility, since Intel completely removed ISA from later chipsets. A big issue is that most motherboards using this chipset don't even have a single ISA slot, as consumers had moved away from them by then. You can find used industrial boards, often made by Intel themselves.If you can get a single ISA slot, you can use a passive backplane to split it into as many slots as you need. ISA is a true bus so all cards are all connected in parallel anyway (which is a reason why they need to be set up with different IRQs, etc.). Have fun assigning resources! PCI is also mostly parallel, but with some card presence and IRQ signals being routed differently to different slots (IIRC). You can use an active PCI splitter (with a PCI-PCI bridge chip) to get more PCI slots.Your best hope for a motherboard might be an Intel 845G (D845) board with AGP, multiple PCI slots and one ISA slot, plus an ISA backplane. Since you already have multiple older machines, you hopefully know all about older Windows versions, video cards, drivers, etc.