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Juko D16-X, can the bios be upgraded?
- Thread starter VERAULT
- Start date
Has anybody tried this JUKO card with the 2M floppy XT BIOS TSR? Even without the ROM chip installed it causes 2M to completely break the floppy drives subsystem right after loading of 2M-XBIOS. I guess some ports of JUKO IDE card overlap the 1.44M HD FDC ports? When JUKO card is physically removed the 2M-XBIOS loads and works fine.
https://theretroweb.com/expansionca...-d16x-users-manual-66f3270adedc4380539776.pdf
You shouldn't need to physically remove the interface card or any attached media, since the card includes a jumper to disable the card.
It seems more likely to me that the "2M floppy XT BIOS TSR" overlaps with memory space typically assigned to these early IDE drives/controllers, rather than the other way round.
Another possibility is that the code in the drive controller's BIOS happens to mangle some memory location that the TSR also wants to use, given that the drive controller apparently does 'PIO mode' (Parallel I/I, no DMA) only.
P.S.
Some of the card's jumper settings affect the ALE and AEN bus signals, etc. Maybe that is part of your problem?
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Consider yourself ignored for being an arsehole.
I'm guessing the problem is with the 2M XT BIOS TSR. The Juko D16-X has the control block I/O address at 3F0h and that probably confuses the 2M TSR for some reason.
That's exactly what bothers me because 3F0-3F7 is the I/O port space for the floppy drive controller?!! How can this work regardless of 2M software?
Well, I can't imagine that the people behind the Juko controller would be so oblivious to the conflict that they would design, manufacture and sell these cards and only *then* discover that they basically have to tell customers "oh btw, you won't be able to use your floppy drives anymore". It has to work in *some* machines at least.
Have you tried it in any other computers (with the FDC support in the actual BIOS, for example)?
Have you tried it in any other computers (with the FDC support in the actual BIOS, for example)?
Even the first IBM PC has FDC support in its "actual" BIOS. The fact JUKO controller seems to work on some machines is not a real understanding of how things works, neither it is an explanation for the problem. Where did you get the information of this JUKO controller I/O address space?
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I was specifically referring to the 1.44 MB support. As you probably know, the FDC has evolved quite a bit over the years and I'm sure that's the reason for this problem. So it will work in some machines but apparently not with the 2M XT BIOS TSR.
Yes, I tried, and the result with AMI BIOS (the same that was used within 2M TSR) is that only the HD transfer is broken. If the media is DD (720K) then it boots. When trying to boot DOS 6.22 from HD media (1.44M) the process with AMI BIOS is stalled right after "Starting MD-DOS..." is shown and the floppy drive remains activated "forever". With AWARD BIOS regardless of media the result is "DISK BOOT FAILURE, INSERT SYSTEM DISK AND PRESS ENTER", though during POST the FDC+floppy drive test passes. All of these problems disappear when the JUKO card (even without its BIOS chip) is removed.
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Is this disk bootable in any other machine? I'm asking because there could be many reasons for this happening. I'm no expert on FDCs and floppy drives, but I'm surprised that it would even get so far as to start booting DOS if there's no support for HD media?
Can I have a look at the source of information about the I/O ports that JUKO IDE card uses and which was used to adjust the XUB to work with it?
Thanks. Was the option ROM's addressing fixed, or was it designed to be with a different base? There are no jumpers on the controller to switch the I/O space, though...It must be moved away from 3Fx.
Yes, the I/O addresses are fixed. That's why I said that they are only displayed for informational purposes in XTIDECFG in this post.
Your best bet is to try to find the exact reason for the conflict. Perhaps it's something specific to how the 2M TSR does things? Maybe you can find some BIOS (or other software) where using HD media works? The fact that there are differences in how AMI BIOS and AWARD BIOS handles things is interesting. But ultimately, it may be impossible to fix this.
Your best bet is to try to find the exact reason for the conflict. Perhaps it's something specific to how the 2M TSR does things? Maybe you can find some BIOS (or other software) where using HD media works? The fact that there are differences in how AMI BIOS and AWARD BIOS handles things is interesting. But ultimately, it may be impossible to fix this.
I don't know why they chose this port space and how it can work, but this is the default configuration of the primary IDE interface of any AT machine. The AT bios is aware of this overlap and designed to work with it. An XT bios / motherboard bus interface may consider 3F0-3F7 of exclusive use of the floppy controller, causing the conflict. Can you set the JUKO card to use a different I/O address? That may work.