Re: Yet another 286 build.

Posted on 2022-06-20, 19:23

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

About the oscillators and other side convos here: Forum conversations were K6/P4 dominated recently so we use your thread for a change. :) Like the setup quite a bit. What you do with the modem ? Do you have a land line, or some adapter through mobile device gets you online ? Get these SIMM slots …

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Re: 3 (+3 more) retro battle stations

Posted on 2022-06-20, 19:15

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

Updated the above post with additional FPU information - check it out. I am sure you will find it interesting. --- About L2 cache chips: Long ago i stopped worrying about how real or fake these higher rated chips are. The better rating hints to me that they were either manufactured to a higher …

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Re: Yet another 286 build.

Posted on 2022-06-20, 04:34

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

The last time i compared two very fast machines 8086 and 286 at same clock speed - 8086 just didn't stand a chance.

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Re: 3 (+3 more) retro battle stations

Posted on 2022-06-20, 00:45

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

Probably the final chapter, for now at least, of my fastest 386 PC adventure - the IBM Blue Lighting 3 storyline. It started on page 1 of this thread with PC-Chips M321 rev 2.3 motherboard and Am386DX-40 CPU. Went through a lot of 386 mobos, including PCBs like Alaris Leopard and Cougar to finally …

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Re: Yet another 286 build.

Posted on 2022-06-19, 18:42

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

thanks for the confirmation.

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Re: Yet another 286 build.

Posted on 2022-06-19, 17:43

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

@Jo22 LOL. Community certification will be enough i guess. Did both of you confirmed that when the FPU is ticking at different rate using the auxiliary oscillator the performance varies ? Asking this because on the motherboard in question here (and at least 2 other boards) i can supply alternative …

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Re: Yet another 286 build.

Posted on 2022-06-19, 00:43

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

I am not sure it is possible to run 287 fpu completelly async to the cpu/base frequency. At least i was not able to achieve that so far. There are few boards that offer 1:1 or 2:3 multiplier controls by effectively pulling up or down voltage on one of the fpu legs. I am not completelly sure if each …

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Re: Yet another 286 build.

Posted on 2022-06-18, 07:21

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

J1 - In position 1-2 FPU uses the main oscillator. In position 2-3 FPU uses the oscillator next to it. If position 2-3 is selected and that oscillator is not present - no FPU. Oscillator's frequency cannot be higher than the main (first) oscillator. J2 - No visible change in perf or other parameters …

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Re: Yet another 286 build.

Posted on 2022-06-18, 03:28

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

i explained the 3 oscillators in previous post.

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Re: Yet another 286 build.

Posted on 2022-06-16, 05:55

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

@appiah4 Hope my words didn't offend the poor mobo. They were mostly a joke. 286 PCBs with integrated IDE/FDD are not that rare but always cool indeed. The serious side of my message was that all 286/386 Headland chipsets are not great in general. --- Having hard time following the conversation …

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Re: Yet another 286 build.

Posted on 2022-06-14, 15:23

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

@simon_e_hall The one here works fine with 4x4Mb RAM. Not picky at all. This thread is turning well with now appiah4 stepping down on 286 path with very mediocre board that should at least partially satisfy Anonymous Coward's lust for this kind of stuff. Which makes me wonder if the different HL …

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Re: Yet another 286 build.

Posted on 2022-06-14, 04:18

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

Saw the listing the other day but passed on it because of the SCAT chipset. Clunky stuff. I have seen 386 motherboards with 72-pin SIMM slots too but such memory slot on 286 is unusual for sure. Too bad SCAT is incapable to utilize the possibilities this kind of RAM brings for overclocking.

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Re: Yet another 286 build.

Posted on 2022-06-13, 22:30

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

For the sake of the broader conversation - i don't find anything charming in early clumsy 286 (and 386 in that count) PCBs. A bit of nostalgia factor that gets quickly erased when the whole system starts acting up and you cannot get it an inch above its 12MHz specification. But at the same time - …

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Re: Yet another 286 build.

Posted on 2022-06-13, 22:23

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

Yes. Up to 16Mb on this board. Looked at my notes. J1 - in position 1-2 FPU uses the base frequency. in position 2-3 FPU uses the crystal oscillator next to it. if the oscillator is not present - no FPU. J2 - no visible change in perf or other parameters of the system J9 - looks like it switches …

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Re: Yet another 286 build.

Posted on 2022-06-13, 18:09

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

Wonder what is the purpose of the second crystal oscillator since is it not present on the mobo here. The more interesting thing is the placeholder for the full can oscillator next to the FPU. Wanted to see if it can provide alternative frequency to the already very fast FPU circuitry on this PCB. …

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Re: 3 (+3 more) retro battle stations

Posted on 2022-06-13, 03:29

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

Just checked on another UUD mobo. You are correct. Interesting i didnt cross this before.

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Re: Yet another 286 build.

Posted on 2022-06-13, 03:16

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

Good to see this coming online. Will follow your progress. The set of components is random indeed, but that adds flavor. Keep in mind that the Promise EIDE Pro ISA does not do well even with modest overclocks. 286 is fun, not sure where you felt negativity towards it. Point us to the sorce of evil …

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Re: 3 (+3 more) retro battle stations

Posted on 2022-06-12, 20:05

by

by pshipkov

in Marvin \ System Specs

in Marvin \ System Specs

@feipoa If you turn-on the parity check on your 1Mb L2 cache modified Biostar UUD motherboard - do you get a warning during POST ? Don't remember checking this back then when applied the mod to one of the mobos here, but fired it up yesterday and saw that.

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Re: Tandy 1000 SL dual monitors possible ?

Posted on 2022-06-07, 05:47

by

by pshipkov

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Utility program called VSWITCH.COM can switch between the built-in Tandy Video and installed ISA video card. Not quite dual monitor setup, but useful in some situations.

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Tandy 1000 SL dual monitors possible ?

Posted on 2022-06-06, 23:22

by

by pshipkov

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Online search reveals nothing, unless i missed some important clues. Looks like the BIOS scans for the presence of a ISA graphics card and picks it in favor of the built-in Tandy adapter. The mode.com mono/co80 and MDA + CGA/EGA/VGA trick does not work obviously. Any hints ?

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