Someone did this years ago along with using a transputer module for a 5x86 cpu upgrade on the inboard.

They never made a care package of files that were needed to be slipstreamed in to allow the extended memory and XT keyboard controller to work under 3.1 (or 95)

I always had trouble getting dos 7 to be bootable on an mfm hard drive , are you using IDE?

I had 95a running on mfm controller with 2 50mb drives.

Had to use drvspace to compress it before installation, and it barely fit.

It was as painful as you'd imagine. I was a kid, poor, and using discarded parts.

I don’t believe anyone before has got Windows 95 working on an Inboard because there was a lot of challenges in doing so. Certainly getting interposers working and Windows 3.11 but 95 has been a long held challenge which I feel I was the first to overcome.

rmay635703 wrote on 2026-08-05, 13:07:

Someone did this years ago along with using a transputer module for a 5x86 cpu upgrade on the inboard.

They never made a care package of files that were needed to be slipstreamed in to allow the extended memory and XT keyboard controller to work under 3.1 (or 95)

I always had trouble getting dos 7 to be bootable on an mfm hard drive , are you using IDE?

I’m booting from a CF card via an Xtide, many people have upgraded and run faster CPU’s via interposers myself included on the Inboard for sure but before yesterday the latest achievable was Windows 3.11 using files from intel to handle the Keyboard nuances.

Mike1978 wrote on 2026-08-05, 12:40:

https://www.vogons.org/download/file.php?id=246895 […]
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If it's a 386 I wonder, why is it reported as a 486?

I wonder what my SIV32L.exe would report, please will you try it, post the initial screen and ideally the Menu->File->Save Local file.

I know it ran OK on 4MB i386 a while ago so 5MB should be OK, that said more should make things faster. I took 158.183 seconds to start-up on an i386 SX @ 16 MHz with 8MB on 09-Apr-2025 so suspect it will take a while to start.

red-ray wrote on 2026-08-06, 10:57:

If it's a 386 I wonder, why is it reported as a 486? […]
Show full quote

Mike1978 wrote on 2026-08-05, 12:40:

https://www.vogons.org/download/file.php?id=246895 […]
Show full quote

If it's a 386 I wonder, why is it reported as a 486?

I wonder what my SIV32L.exe would report, please will you try it, post the initial screen and ideally the Menu->File->Save Local file.

I know it ran OK on 4MB i386 a while ago so 5MB should be OK, that said more should make things faster. I took 158.183 seconds to start-up on an i386 SX @ 16 MHz with 8MB on 09-Apr-2025 so suspect it will take a while to start.

Yes it will heavily make usage of the swapfile.
If you cannot install more RAM try to move the swapfile to a second HDD if possible. But perhaps your CF card is fast enough to switch from small reads to small writes.
And I have seen that everything is in compatiblity mode. That's really awful on a 386sx. Please have a lot of patience on that run.

red-ray wrote on 2026-08-06, 10:57:

If it's a 386 I wonder, why is it reported as a 486? […]
Show full quote

Mike1978 wrote on 2026-08-05, 12:40:

https://www.vogons.org/download/file.php?id=246895 […]
Show full quote

If it's a 386 I wonder, why is it reported as a 486?

I wonder what my SIV32L.exe would report, please will you try it, post the initial screen and ideally the Menu->File->Save Local file.

I know it ran OK on 4MB i386 a while ago so 5MB should be OK, that said more should make things faster. I took 158.183 seconds to start-up on an i386 SX @ 16 MHz with 8MB on 09-Apr-2025 so suspect it will take a while to start.

I can explain it the base card is an Intel Inboard 386/pc but I have running in the card a CPU interposer I-O Data PK-A486BL 386/486 Blue Lightning Processor Upgrade CPU BL3 60MHz 486DLC including FPU
Crystal oscillator changed to 40Mhz from 32Mhz

The CPU has 486 instruction set.

At the minute it’s running at 40Mhz if I get the revto486.sys loaded like I could under DOS / Windows 3.11 then I may get it back to the dizzy heights of 83.5mhz that I got it to before.

Disruptor wrote on 2026-08-06, 12:52:

Yes it will heavily make usage of the swapfile. If you cannot install more RAM try to move the swapfile to a second HDD if possi […]
Show full quote

red-ray wrote on 2026-08-06, 10:57:

If it's a 386 I wonder, why is it reported as a 486? […]
Show full quote

Mike1978 wrote on 2026-08-05, 12:40:

https://www.vogons.org/download/file.php?id=246895 […]
Show full quote

If it's a 386 I wonder, why is it reported as a 486?

I wonder what my SIV32L.exe would report, please will you try it, post the initial screen and ideally the Menu->File->Save Local file.

I know it ran OK on 4MB i386 a while ago so 5MB should be OK, that said more should make things faster. I took 158.183 seconds to start-up on an i386 SX @ 16 MHz with 8MB on 09-Apr-2025 so suspect it will take a while to start.

Yes it will heavily make usage of the swapfile.
If you cannot install more RAM try to move the swapfile to a second HDD if possible. But perhaps your CF card is fast enough to switch from small reads to small writes.
And I have seen that everything is in compatiblity mode. That's really awful on a 386sx. Please have a lot of patience on that run.

Performance so far hasn’t been much worse than with windows 3.11 but I expect the ram to be the bottleneck alongside the 4.77mhz bus. But it does run and I’ll be trying to squeeze a lot more out of it when I can.

I may explore a slave CF on xtide perhaps to act purely for a swap file. Though it likely wouldn’t do a lot if sharing the same channel. It may actually make it slower. There are other devices but again running in compatibility mode on the SCSI card. So perhaps marginal gains. The CF is likely faster than the spinning rust of its day even though on the 8bit card.

wierd_w wrote on 2026-08-05, 13:19:

I had 95a running on mfm controller with 2 50mb drives.

Had to use drvspace to compress it before installation, and it barely fit.

It was as painful as you'd imagine. I was a kid, poor, and using discarded parts.

Love this, I saw someone running win95 on MFM it was an old video but love when people do crazy things that was never meant to be done!

Mike1978 wrote on 2026-08-07, 17:33:

wierd_w wrote on 2026-08-05, 13:19:

I had 95a running on mfm controller with 2 50mb drives.

Had to use drvspace to compress it before installation, and it barely fit.

It was as painful as you'd imagine. I was a kid, poor, and using discarded parts.

Love this, I saw someone running win95 on MFM it was an old video but love when people do crazy things that was never meant to be done!

I had to 'get creative' to install it.

Drvspace *first*, used Fastlynx to copy the install files to the second hard drive.

Custom install with lots of stuff turned off. 90mb was the maximum you could squeeze off that way, and it completely filled the drive.

Hilariously, 95a has mfm controller drivers.

Not that it helped much; it was painfully slow to access and use.

Mike1978 wrote on 2026-08-07, 17:23:

I can explain it the base card is an Intel Inboard 386/pc but I have running in the card a CPU interposer I-O Data PK-A486BL 386 […]
Show full quote

red-ray wrote on 2026-08-06, 10:57:

If it's a 386 I wonder, why is it reported as a 486? […]
Show full quote

Mike1978 wrote on 2026-08-05, 12:40:

https://www.vogons.org/download/file.php?id=246895 […]
Show full quote

If it's a 386 I wonder, why is it reported as a 486?

I wonder what my SIV32L.exe would report, please will you try it, post the initial screen and ideally the Menu->File->Save Local file.

I know it ran OK on 4MB i386 a while ago so 5MB should be OK, that said more should make things faster. I took 158.183 seconds to start-up on an i386 SX @ 16 MHz with 8MB on 09-Apr-2025 so suspect it will take a while to start.

I can explain it the base card is an Intel Inboard 386/pc but I have running in the card a CPU interposer I-O Data PK-A486BL 386/486 Blue Lightning Processor Upgrade CPU BL3 60MHz 486DLC including FPU
Crystal oscillator changed to 40Mhz from 32Mhz

The CPU has 486 instruction set.

At the minute it’s running at 40Mhz if I get the revto486.sys loaded like I could under DOS / Windows 3.11 then I may get it back to the dizzy heights of 83.5mhz that I got it to before.

Is ram on the upgrade board with the BL3 ?

Mike1978 wrote on 2026-08-07, 17:23:

I can explain it the base card is an Intel Inboard 386/pc but I have running in the card a CPU interposer I-O Data PK-A486BL 386/486 Blue Lightning Processor Upgrade CPU BL3 60MHz 486DLC.

Thank you, I half guessed this could be the situation. Does the Intel Inboard 386/pc have a motherboard cache?

Some time ago I updated SIV to detect and report the 486DLC L1 cache size so I would be good if you tried SIV32L.exe and posted the screen shot and Menu->File->Save Local file so I can see how the new code does.

red-ray wrote on 2026-08-09, 16:49:

Mike1978 wrote on 2026-08-07, 17:23:

I can explain it the base card is an Intel Inboard 386/pc but I have running in the card a CPU interposer I-O Data PK-A486BL 386/486 Blue Lightning Processor Upgrade CPU BL3 60MHz 486DLC.

Thank you, I half guessed this could be the situation. Does the Intel Inboard 386/pc have a motherboard cache?

Unfortuneately the Intel Inboard 386/PC does not contain any cache where the the Intel Inboard 386/AT does have 64 kB of cache.
Perhaps it has something to do with the DMA problem. PC and PC/XT use an 8 bit MFM controller which uses DMA on every data transfer. In the AT access through PIO is faster.

Mike, do you face any DMA problems with the BL?
Perhaps the solution flushes the BL's cache on every DMA access to overcome this problem.

douglar wrote on 2026-08-09, 16:18:

Mike1978 wrote on 2026-08-07, 17:23:

I can explain it the base card is an Intel Inboard 386/pc but I have running in the card a CPU interposer I-O Data PK-A486BL 386 […]
Show full quote

red-ray wrote on 2026-08-06, 10:57:

If it's a 386 I wonder, why is it reported as a 486?

I wonder what my SIV32L.exe would report, please will you try it, post the initial screen and ideally the Menu->File->Save Local file.

I know it ran OK on 4MB i386 a while ago so 5MB should be OK, that said more should make things faster. I took 158.183 seconds to start-up on an i386 SX @ 16 MHz with 8MB on 09-Apr-2025 so suspect it will take a while to start.

I can explain it the base card is an Intel Inboard 386/pc but I have running in the card a CPU interposer I-O Data PK-A486BL 386/486 Blue Lightning Processor Upgrade CPU BL3 60MHz 486DLC including FPU
Crystal oscillator changed to 40Mhz from 32Mhz

The CPU has 486 instruction set.

At the minute it’s running at 40Mhz if I get the revto486.sys loaded like I could under DOS / Windows 3.11 then I may get it back to the dizzy heights of 83.5mhz that I got it to before.

Is ram on the upgrade board with the BL3 ?

No the CPU upgrade and ram upgrade are two separate entities. The daughterboard can be found below:

https://forum.vcfed.org/index.php?threads/inb … on-clone.78562/

red-ray wrote on 2026-08-09, 16:49:

Mike1978 wrote on 2026-08-07, 17:23:

I can explain it the base card is an Intel Inboard 386/pc but I have running in the card a CPU interposer I-O Data PK-A486BL 386/486 Blue Lightning Processor Upgrade CPU BL3 60MHz 486DLC.

Thank you, I half guessed this could be the situation. Does the Intel Inboard 386/pc have a motherboard cache?

Some time ago I updated SIV to detect and report the 486DLC L1 cache size so I would be good if you tried SIV32L.exe and posted the screen shot and Menu->File->Save Local file so I can see how the new code does.

Happy to do so when I get home to it. I’m on vacation so it will be a few weeks.

Disruptor wrote on 2026-08-09, 19:26:

Unfortuneately the Intel Inboard 386/PC does not contain any cache where the the Intel Inboard 386/AT does have 64 kB of cache. […]
Show full quote

red-ray wrote on 2026-08-09, 16:49:

Mike1978 wrote on 2026-08-07, 17:23:

I can explain it the base card is an Intel Inboard 386/pc but I have running in the card a CPU interposer I-O Data PK-A486BL 386/486 Blue Lightning Processor Upgrade CPU BL3 60MHz 486DLC.

Thank you, I half guessed this could be the situation. Does the Intel Inboard 386/pc have a motherboard cache?

Unfortuneately the Intel Inboard 386/PC does not contain any cache where the the Intel Inboard 386/AT does have 64 kB of cache.
Perhaps it has something to do with the DMA problem. PC and PC/XT use an 8 bit MFM controller which uses DMA on every data transfer. In the AT access through PIO is faster.

Mike, do you face any DMA problems with the BL?
Perhaps the solution flushes the BL's cache on every DMA access to overcome this problem.

The blue lightning has 16kb l1 cache as I recall and up to 3x clock multiplier.

The original 16mhz Intel 386 would have had none

I had been controlling some of the multiplier via software with revto486.sys to increase the multiplier to 2x and that did also do things with the CPU registers

I have a screenshot but not from the win95 boot this is dos / 3.11 where it works seemlessly

So far getting the revto486 to boot on 95 has proven difficult. One to revisit.

I forgot to mention the code I posted on my repo with the inboard emulated in 86 box, it will be merged to 86 box in the main repo soon I did submit it already but there maybe a 101 bug introduced. I’ll fix on my return from my vacation.

The 86 box code on my repo did come from unipcemu by SuperFury which I ported to 86 box but I did fix a few little nuances as I did so if I recall extended ram from 6mb to a truer 4mb on the daughterboard and 1mb in the inboard.

My repo has the version I built with.

wierd_w wrote on 2026-08-07, 18:55:

Hilariously, 95a has mfm controller drivers.

THat's pretty normal.
IDE is more or less register-compatible with MFM/RLL.
They just moved the controller inside the hard drive.
The "controller" in the slot is just a dumb buffer, switching on when the correct io addresses are contacted.