Reply 600 of 611, by nathanieltolbert
pentiumspeed wrote on 2023-02-20, 17:35:Again that is non-sense. There is no new allocations or something. To make the compatibility to work the VLB i/o board had to be exactly same design as ISA in hardware, irq and addresses as ISA so DOS and windows to work otherwise would require a IDE VLB driver for the VLB IDE chip.
If the MPU-IPC-T worked while the hardMPU failed then something is not quite right with HardMPU. This needs to be debugged properly and revise the HardMPU's hardware or firmware. There was same issue on a clone soundcard and the person who designed this found the issue in firmware for the sound card clone and fixed it.Cheers,
All I can say is what I am observing. Hence the comment of 'I think'. It does appear to be something with the way the HardMPU gets the resources though. On one of the Socket 7 boards I have I couldn't get the HardMPU to work until I changed the IRQ to 3. Then it worked okay. Thinking this was strange I went into the BIOS and I saw that the first PCI IRQ allocation was IRQ9 and then incremented by one for each PCI slot through PCI Slot 4. On a curiosity I increased the IRQ for each PCI slot by one increment, so instead of starting at IRQ9, it started at IRQ10. After doing this the HardMPU worked at IRQ2/9. I don't know why this was. PCI slot 1 was not populated with a card, so why would the HardMPU would fail to use IRQ9? When I changed the PCI Slot IRQ it started working. I don't know enough about system resource allocation and resource conflict to know why it didn't work. Only that it didn't. I would have guessed that since there was nothing using the PCI slot that IRQ9 would be free to use for whatever. At least that was how I thought resource allocation worked on PCs outside of hard fixed addresses. But for the HardMPU card this didn't work. If you know what could be causing this I would be really interested in knowing. It seems very strange to me.