Re: Where can I find "AMIBCP" (for DOS) ?

Posted on 2021-07-09, 02:10

by

by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

No that is not the original AMIBCP for Windows 1.0, was hoping to find it..... Again though, is there something specific you are trying to do with a 10/10/94 bios? Like the other thread I posted for non-WinBIOSes, it may be easier to analyze the bios and figure out how to do what you want, although …

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AMI Color BIOS (1993 and earlier) modification in hex editor

Posted on 2021-07-08, 01:40

by

by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I saw the AMIBCP search thread was active again. In talking with some of the members about the PS/2 mouse hardware modifications on their boards, there are at least a few modifications you can do with these BIOSes even without having AMIBCP, found by digging around in the hex dump, DOS DEBUG, and in …

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Re: Where can I find "AMIBCP" (for DOS) ?

Posted on 2021-07-06, 16:36

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by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

The oldest Windows version I have is 2.42. The oldest DOS version I have is 5.11E. It would be nice to get a hold of every version between 1.0 and 5.0, but I'm feeling pretty pessimistic about this. The odds are about as good as finding a MR BIOS image for the VLSI topcat. I would like a copy of …

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Re: Is there a dosbox version for 486?

Posted on 2021-07-06, 15:23

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by jakethompson1

in PC Emulation

in PC Emulation

It's an interesting idea but yeah I don't think full emulation would be the way to go. I wonder if you wanted to implement the features you mentioned, if you most likely would end up creating something along the lines of SoftICE.

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Re: Where can I buy? CMOS 4-PIN Battery Replacement

Posted on 2021-06-16, 22:28

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by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

maxtherabbit wrote on 2021-06-16, 22:09: It's a standard 0.100" pitch pin header. You can get them at digikey or ebay or anywhere Digi-Key also stocks the whole thing as BH3AA-211. Pricier, but maybe not if you factor in shipping on two orders.

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Re: IDE support for more than 8 GB HDD storage on Biostar MB-8433UUD

Posted on 2021-06-15, 23:55

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by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

On Wikipedia it looks like PIO mode 3 was only rated for 11 MB/s anyway, so there was no way it would match the UltraDMA card. Programmed I/O ties up the CPU running a REP INSD instruction to read from the bus only 32 bits at a time. I don't know whether the fault for the slow times (vs. what PIO3/ …

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Re: Can't get into CMOS setup on old 486.

Posted on 2021-06-13, 16:11

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by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

In effect I suppose the improperly configured cache made the first 64K work incorrectly. This was also mentioned earlier the discussion - BIOS was never able to proceed far enough. Interesting. I'm surprised it wouldn't give you the opportunity to enter CMOS setup before enabling the external cache …

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Re: Can't get into CMOS setup on old 486.

Posted on 2021-06-11, 15:11

by

by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

You've mentioned that the board has a 50 MHz crystal. I thought that for 386 CPUs, the crystal is double the clock speed, and for 486 CPUs, the crystal is equal to the clock speed, but with this being a DX2 CPU, it would actually be half the clock speed. So I think the crystal should be 25 MHz. …

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Re: Can't get into CMOS setup on old 486.

Posted on 2021-06-11, 01:25

by

by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I think one of those old BIOS chips have a failed/corrupted section in one of them. Have a P2B bios chip that has a bad spot and would lock during POST, found it with a TL866 when trying to read the contents to make sure it was same as what was supposed to be programmed in it when it failed a flash …

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Re: IDE support for more than 8 GB HDD storage on Biostar MB-8433UUD

Posted on 2021-06-10, 05:29

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by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

To reduce the latency with the onboard IDE in PIO4 mode, I was considering giving up my Promise IDE controller on my setup to add a second Voodoo2 card for SLI operation. Has anyone tried running a Samsung SSD SATA drive with a SATA to IDE adapter on the MB-8433UUD's internal IDE controller? Hey I …

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Re: Can't get into CMOS setup on old 486.

Posted on 2021-06-10, 05:02

by

by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Unfortunately I think you're going to need the POST card. If there's any way to figure out the last code before it resets at least you could dig through the BIOS ROM and try to figure out what it's doing... Another shot in the dark. Do you have a PC speaker connected? I notice one of the things it …

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Re: Can't get into CMOS setup on old 486.

Posted on 2021-06-10, 02:57

by

by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Do you have a card to display the POST codes generated by the bios?

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Re: Garage Sale PC won't let me install Windows 95 or 98

Posted on 2021-06-09, 17:31

by

by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Something I don't think has been mentioned yet is to make sure there is a voltage regulator present, if you are running the Vcore of that MMX (2.8v) too high (say, 3.3v like a regular Pentium uses) it will overheat and have strange activity like this. But why would it overheat during Win9x …

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Re: Can't get into CMOS setup on old 486.

Posted on 2021-06-09, 00:49

by

by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

Maybe. The NumLock comes on when it's supposed to. The CapsLock and ScrollLock lights do not light up. I cannot toggle any of the LEDs via the keyboard. The only keyboard activities I can do are: 1- to reset the system. 2- Abort the memory test via . 3- Generate a Keyboard Stuck error by holding a …

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Re: Garage Sale PC won't let me install Windows 95 or 98

Posted on 2021-06-09, 00:21

by

by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

65C02 wrote on 2021-06-07, 19:46: -During the File Copy stage of 95/98/ME setup, the computer will freeze. Sometimes the screen gets garbled when it freezes. I tried with a different video card and got the same result. Check the BIOS setup for any "virus protection" or "boot sector protection" …

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Re: Need help resurrecting a 486 dumpster find

Posted on 2021-05-30, 22:22

by

by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

I'm still trying to figure out what causes the screen corruption during reading from a floppy drive. To me it seems as if the IO controller is writing to the video RAM (if that's even possible..) Data from the floppy is transferred to main memory using DMA. The mainboard (the DMA controller) asks …

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Re: 3 (+3 more) retro battle stations

Posted on 2021-03-22, 17:55

by

by jakethompson1

in Marvin \ System Specs

in Marvin \ System Specs

What was your approach of determining dma/no-dma ? I didn't think IDE used DMA at all in the 486/VLB-era. I thought DMA was introduced with the Intel Triton Pentium chipset. Wasn't this why SCSI was a "power user" feature back then. Since Linux is up as a topic, looking through the source code for …

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Re: 3 (+3 more) retro battle stations

Posted on 2021-03-22, 04:08

by

by jakethompson1

in Marvin \ System Specs

in Marvin \ System Specs

lol. Ubuntu is not fit for human consumption. Pretty much doubled the I/O metrics to ~7-9Mb/s from ~3-4Mb/s before. That same speed increase was also observed in Win95 osr2? Seems odd that Win95 OSR2 wouldn't have the DMA drivers included with the OS. I had the impression that those UMC 8886 …

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Re: The Ultimate 486 Benchmark Comparison

Posted on 2020-12-27, 04:35

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by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

feipoa wrote on 2020-12-27, 03:57: From what I understand, normally the front-side bus clock rate is at or around 33.3333 MHz, so more like 99.9999 MHz. People tend to round out the decimal places. It always makes me think of an LP record.

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Re: DOS UDMA

Posted on 2020-12-13, 17:49

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by jakethompson1

in Marvin \ General Old Hardware

in Marvin \ General Old Hardware

There is a common API implemented by most memory managers called "VDS" (virtual-mode DMA specification), but it adds a lot of complexity to the quite simple IDE implementation in the BIOS and adds a dependency from the BIOS to the memory manager. It seems BIOS writers were reluctant to implement …

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