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Thread: FPGA accelerator cards

  1. #11

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    Quote Originally Posted by Exceter View Post
    6-8mhz would be fantastic
    mhz or MHz! The difference is 1 000 000 000 times.

  2. #12

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    Quote Originally Posted by george View Post
    mhz or MHz! The difference is 1 000 000 000 times.
    MHz. I certainly don't want something slower than the standard 4.77MHz :P
    Once upon a time, the internet sucked because it came through the phone. Now the phones suck because they come through the internet.

  3. #13
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    Quote Originally Posted by george View Post
    mhz or MHz! The difference is 1 000 000 000 times.
    Incorrect. The answer is non-deterministic as the H is also lower case - meaning the unit measurement is also ambiguous - eg. not referring to the unit of measure (Hz) named after the German Physicist Heinrich Hertz. 6 milli-Hogsheboygans could be pretty darned fast.
    "Good engineers keep thick authoritative books on their shelf. Not for their own reference, but to throw at people who ask stupid questions; hoping a small fragment of knowledge will osmotically transfer with each cranial impact." - Me

  4. #14

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    Quote Originally Posted by Exceter View Post
    How hard would it be to make an 8-bit isa card using an FPGA and software cores that does the same thing that the old accelerator cards did?
    There are no easily-solderable 5V-compatible FPGAs. Basically, you'd need a lot of level shifters and good soldering equipment. Also, the mainboard CPU can't be overridden by an ISA card, so you'd need to run a cable from the old CPU socket to the ISA card. Apart from that... it is nothing that hasn't been done before. It isn't hard, but comes with lots of practical annoyances, requires a lot of work, and needs knowledge from many different domains.

    Performance improvements are limited by the bus speed, so there's not much point to having a fast CPU on the ISA card. One could also run a full system inside the FPGA while a host program providing I/O runs on the existing system. From a user's point of view, it would feel like regular emulation, and from a designer's point of view... you can do that without the existing system in the first place.

    Peripherals are a different story.

  5. #15
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    Quote Originally Posted by Svenska View Post
    There are no easily-solderable 5V-compatible FPGAs. Basically, you'd need a lot of level shifters and good soldering equipment. Also, the mainboard CPU can't be overridden by an ISA card, so you'd need to run a cable from the old CPU socket to the ISA card. Apart from that... it is nothing that hasn't been done before. It isn't hard, but comes with lots of practical annoyances, requires a lot of work, and needs knowledge from many different domains.

    Performance improvements are limited by the bus speed, so there's not much point to having a fast CPU on the ISA card. One could also run a full system inside the FPGA while a host program providing I/O runs on the existing system. From a user's point of view, it would feel like regular emulation, and from a designer's point of view... you can do that without the existing system in the first place.

    Peripherals are a different story.
    For me I can't see the point. A vintage system is slow because its vintage or vintage because its slow. Speeding up such systems usually breaks a few things with software timing loops. If its not original its not so much fun. I did faster disks in my IBM PC Server 500 but only because the originals were becoming un reliable....
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  6. #16
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    Moving from a pc/xt to an at presented some compatibility issues. Ok they were minor, and if a vendor had any brains they would provide a patch. There always were compatibility issues. Accelerators were very much a part of the landscape in the 80s. I can't imagine too many people who wouldn't want say an IBM PGC in their old box. But that rules out anything other then cga based software. And even then the cga emulation likely wasn't perfect.
    Last edited by tipc; October 10th, 2019 at 07:49 AM.

  7. #17
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    Quote Originally Posted by Exceter View Post
    6-8mhz would be fantastic
    8088 equivalent? That's easy and only requires an XCO and a couple of wires (and a replacement CPU).

  8. #18
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    Quote Originally Posted by g4ugm View Post
    For me I can't see the point. A vintage system is slow because its vintage or vintage because its slow. Speeding up such systems usually breaks a few things with software timing loops. If its not original its not so much fun. I did faster disks in my IBM PC Server 500 but only because the originals were becoming un reliable....
    I'm the same way. You get into this because of the cool hardware and interesting software. If you need to start cramming in accelerators and enhancements because its not how you want it to feel then get ready to run into a lot of compatibility issues and skyhigh costs. Look how deep pocketed most of the Amiga community is.
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  9. #19
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    I threw a V-20 into my Tandy 1000 to try to eke a little extra speed out of it, but I kind of consider it a special case. The 1000 line had models that covered the CPU speed spectrum from original XT to low-end AT while leaving almost all the rest of the hardware unchanged, so there's a fair body of software that "runs" on all of them but is just a *little* too laggy and slow on the first and second generation models. It's a place where even a modest 40-60% boost might get you to the other side of the usability line while retaining all the other hardware in the machine.

    (Unfortunately these machines also use custom chips that, outside of some exceptions, make simple "PC Sprint"-style clock gooses hard to pull off.)

    Outside of edge cases like that it probably does make more sense to just move up to the next category of machine. (IE, park a real AT next to your XT.) That is unless playing with oddball hardware like accelerator cards specifically floats your boat, in which case go hawg wild. A modern recreation of the Intel Inboard 386 with an Atom CPU would be a hoot.(*)

    (*Edit: Seriously, now I want to see someone put a small SBC equipped with CPU that has modern VT/IOMMU extensions into an ISA slot/8088 CPU socket. Then use hypervisor mechanisms to allow a DOS session running on the card to directly access the hardware in the parent machine. Just think of all the wait states...)
    Last edited by Eudimorphodon; October 10th, 2019 at 01:27 PM.

  10. #20

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    Quote Originally Posted by Exceter View Post
    That part wouldn't be as bad as you might think because people have already implemented many of the old microprocessors in an fpga. It's not something that you'd have to do yourself. I was reading a blog post just yesterday about a guy who implemented an 8088 in an fpga and used it to boot into dos.
    Am I that guy?

    PS: Im going to open source the MCL86 and a number of my projects onto Github very soon...

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