VOGONS


Reply 20 of 26, by Mike1978

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Mike1978 wrote on 2026-08-09, 20:00:
The blue lightning has 16kb l1 cache as I recall and up to 3x clock multiplier. […]
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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. […]
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red-ray wrote on 2026-08-09, 16:49:

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.

The attachment IMG_0766.jpeg is no longer available

I got the equivalent of running revto486.sys but using ctchip34.exe and set a number of registers at boot via autoexec.bat I’ve got the CPU speed back at 2x as wanted and the L1 cache enabled.

Reply 21 of 26, by red-ray

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Thank you for trying, given msvcrt is missing I suspect you need to install vcredist_60_x86.exe, see Re: SIV support for 386/486/586 class CPUs and 3Dfx + Matrox GPUs. It would also be a good idea to install the Tahoma Font+DLLs.

Mike1978 wrote on Yesterday, 17:03:

Gave this a go and got a missing msvcrt error is this a known requirement on Win 95 ? I’m recalling this from memory as it was very late when I tried it.

Reply 22 of 26, by Mike1978

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As for updates on what else is now working.

I had to patch the Creative Labs Soundblaster Pro driver and now my SB pro 2 ct1600 is now fully working.

Network is working 3c509b standard driver worked immediately and just needed to be hand configured

ATI Mach 8 Ultra driver from Windows 95 unmodified worked fully also though I had to configure it manually once done it took and worked so all good runs at 1024x768x256

I identified an issue with the FDD drives I have an extended bios and 1.44 support via a Sergey Kisalev floppy controller with serial. Initial thoughts are it’s trying to load via bios but not there and real mode of course. Adding the windows Floppy driver Adapter in device manager got it further actually attempts to show the content of the drive but fails part way through. The second 1.2mb 5.25 geometry also misidentifies as 1.44 3.5 so some work there patching the windows driver wasn’t being read so may need to do some work on the DMA similar to the SB Pro driver.

It does work in DOS and previously in Windows 3.11 so it should be possible to find a solution.

Likewise all drives currently loading in real mode so would be good to try and fix, adding in device manager defaults to IRQ14 on a standard IDE / ESDI controller so again likely need to patch the driver

Progress though with video, sound and network all working and getting the CPU cache working and Speed clocked appropriately.

Never will be speedy but it’s working

All details on my git, I’ve also been patching and fixing up the emulation in 86 box as well, it is now in the main 86 box branch.. There’s potentially still a few issues but it’s been invaluable for development and test.

Reply 23 of 26, by Mike1978

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red-ray wrote on Yesterday, 17:12:

Thank you for trying, given msvcrt is missing I suspect you need to install vcredist_60_x86.exe, see Re: SIV support for 386/486/586 class CPUs and 3Dfx + Matrox GPUs. It would also be a good idea to install the Tahoma Font+DLLs.

Mike1978 wrote on Yesterday, 17:03:

Gave this a go and got a missing msvcrt error is this a known requirement on Win 95 ? I’m recalling this from memory as it was very late when I tried it.

Thanks I think I actually have that on disk I think to deploy. Will try once more after I confirm.

Reply 24 of 26, by Mike1978

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red-ray wrote on Yesterday, 17:12:

Thank you for trying, given msvcrt is missing I suspect you need to install vcredist_60_x86.exe, see Re: SIV support for 386/486/586 class CPUs and 3Dfx + Matrox GPUs. It would also be a good idea to install the Tahoma Font+DLLs.

Mike1978 wrote on Yesterday, 17:03:

Gave this a go and got a missing msvcrt error is this a known requirement on Win 95 ? I’m recalling this from memory as it was very late when I tried it.

Hi Ray

Ok update for you, the distribution fixed the error but the fonts reported as not being valid and failed to load.

I’ve got it to load it took minutes. Currently saving the information.

Minor misreporting on ram but unsurprisingly saying 8mb I have 5mb but seems to be the same in a few apps I tried re the ram.

Saving to local as I speak and it’s going to take some time to complete. The disk is slow and real mode atm hopefully one I can address but the bus speed will always be tricky and likely so will disk.

I’ll share the file when complete

Mike

Reply 25 of 26, by Mike1978

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Mike1978 wrote on Yesterday, 17:03:
Hi again, […]
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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.

Hi again,

Gave this a go and got a missing msvcrt error is this a known requirement on Win 95 ? I’m recalling this from memory as it was very late when I tried it.

I’ll give it another spin after a few more installs as it maybe packaged up with the likes of MS Internet explorer 5.5 sp2 etc.. it is OSR1 and will in the future be giving osr2 another attempt.

Mike

I had to kill it it was making the box unresponsive but here's the partial file output

Edit - it got further than I thought. It looked dead so I pulled it, but the CPU sections did complete, so there is usable data in there after all.

On the 486DLC L1 cache detection you asked me to try, the new code reports:

L1 Unified Cache 4-way 16-byte 8KB
L2 Unified Cache Unknown

The Blue Lightning BL3 has 16KB, so it is reading half. My guess is it is falling back to the generic i486 default rather than probing, because CPUID is not available on this chip - [_]CPUID is clear in the [cpuid] section - but you will know far better than me whether the new detection path needs CPUID to run at all.

The clock is the part I would most like your view on:

CPU-0 Generic 486 DX2 STK 65.131MHz CPU 65.131MHz FSB 32.565MHz
CPU-0 65.1MHz x2 32.6MHz

The x2 is correct and genuinely useful to see confirmed - that is the clock multiplier I set with CTCHIP34, so it is holding. But the base reads 32.6MHz and I have a 40MHz crystal fitted, swapped up from the original 32MHz. CheckCPU and CheckIt both measure around 83.5MHz from DOS, which fits 40 x 2. SIV under Windows makes it 65, which fits the old 32MHz crystal.

So either the clock is not holding under Windows, which would be well worth me chasing as there is real performance in it, or the timing loop is struggling on this hardware. With no TSC on this chip I assume it is PIT calibrated, and this machine is awkward - the Inboard has its own local bus and speed register while the ISA side stays at 4.77MHz. How much would you trust that figure here?

Two other things you may want, since SIV is not going to meet this hardware often:

- RAM reads 8.00MB against 5MB actual, and it reports "Chips 1 SIMMs 4" plus two 4MB SPD entries. There are no SIMM sockets on this machine at all - it is 1MB on the Inboard plus a 4MB piggyback.
- Every section took 7 to 14 seconds, a couple over 20 ([features] was 21s), which is what made it look hung rather than slow. I assume that is SMBus/ACPI/PnP probing timing out against a 1983 machine.

The BIOS line came out exactly right, for what it is worth: "Unknown Motherboard BIOS C1.10 Copyright IBM Corp 1981 05/09/86" - that is the correct 09MAY86 5160 ROM.

Mike

Second edit - correcting myself on the cache, having gone through the file properly.

The 8KB is not a failed probe, it looks like it never probed at all. "486DLC" does not appear anywhere in the file, SIV classifies the chip as "Generic" throughout, and there is a line reading "CPU Tweak is Not Supported for the Generic 486 DX2 65MHz CPU". The 8KB 4-way 16-byte figure is just the stock Intel 486DX descriptor, so it would print the same whether the cache is enabled or not.

More usefully, and this is what I missed first time round - the very last line of the file is the latency section header with nothing under it. That is exactly where I killed it. So the cache latency test, the one thing that would have measured rather than classified, never ran.

What sits immediately before it explains why the machine looked dead. It was not hung at all, it was benchmarking:

benchmark-dd Integer 2, Float 2 - 106.44 seconds
benchmark-dw Integer 1, Float 2 - about 87 seconds
latency - killed here

So I pulled it roughly two minutes too early, right as the cache test was starting. That one is on me, not on SIV.

Happy to run it again and leave it completely alone this time if the latency numbers would be useful to you. Just say and I will let it run to completion however long it takes, and post the full file.

Reply 26 of 26, by Disruptor

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Mike1978 wrote on Yesterday, 22:34:

More usefully, and this is what I missed first time round - the very last line of the file is the latency section header with nothing under it. That is exactly where I killed it. So the cache latency test, the one thing that would have measured rather than classified, never ran.

That is what I have noted on some of my older machines too.
First I thought it was due to the low RAM, but my 16 or 32 MB should be fine for that checks.