Bancho wrote on 2021-04-22, 20:13:

I've put together a 486 PC based around a Asus VL/EISA-486SV1. The issue I'm seeing is after installing DOS, floppy disks refuse to read. I 'think' the drive is being recognised as a 360k/1.2m Drive. I get "Sector cannot be found" when trying to run things from a floppy.

On typical 486 computers, drives don't get "recognized", but you need to enter the correct drive type in the CMOS setup. Make sure A: is not configured as 1.2MB drive.

mkarcher wrote on 2021-04-22, 20:54:

On typical 486 computers, drives don't get "recognized", but you need to enter the correct drive type in the CMOS setup. Make sure A: is not configured as 1.2MB drive.

Yeah, the drive is configured correctly in the bios, is recognised at post test, and will boot from floppy. As I said, I installed DOS 6.22 from 3 1.44mb floppy disks. After dos had installed, when booting from the HD, I can read the contents of the floppy using DIR, but when I try to access something from the floppy, I get the Sector cannot be found error.

After booting from the HD, can you format a floppy, and does it then work? Any differences in the config or autoexec between 6.22 on the floppy and HD? Did the floppy read smoothly when installing 6.22 on the HD or was the head having to do a lot of seeking back and forth? Does booting from the HD have problems reading both 1.44 and 720 disks? Can you try running both floppy and HD on the Winbond IO card (I think you've tried both on the Tekram)? Is there any difference in the IMD alignment test when booting from floppy or HD (check the read Data option)? When booting from the floppy can you access the HD with no problems?

To be honest this is all random thoughts as I can't think of any reason why booting from the HD would matter at all. I vaguely remembering we had a 486 with a Tekram for both floppy and HD, and don't remember having any problems with it.

Sounds weird. To eliminate a driver conflict (yes can happen in DOS) boot off the HD holding F5 when you see 'Starting MS-DOS' which should bypass the Config and Autoexec files. Then try to read a floppy.

Being an EISA board, don't you need to run some config utility to set up the peripherals?

What controller are you using for IDE and Floppy?
IS it ISA, VLB or EISA?

Hi All,

I've tried everything that has been suggested! Still no joy in reading disks when booting from the HD. I re-installed dos on a Compact Flash card (265mb) instead of the HD in-case there was some conflict, but exactly the same.

Floppy Drive is a Mitsumi D359T6

This is the EISA HDD Controller

This is the ISA Super I/O (HDD Disabled)

This is what happens if you boot from the hdd, and try to run something from the Floppy Disk.

If I boot from the floppy, Program runs

If i try to format a floppy when booted from the HD and using the format command this happens. Its like its reading the disks in the wrong format. But the BIOS is set correctly (3.5 1.44mb) This behaviour is the same when using either controllers.

Which Floppy port are you using? Did you try the other one?
You should also disable any Floppy ports that you are not using. If the one on the EISA IDE-controller cannot be disabled, use it and disable the one on the multi-IO.

If I use the Super I/O Card, I disable the floppy controller on the EISA card.

If I take the Super I/O out, I obviously enable the Floppy Controller on the EISA card.

But either way, both exhibit the same behaviour. What I'm struggling to fathom is why it works when booting from a the DOS install Disk and I can actually install DOS to the HD from the Floppy drive, but after installation, and booting from the HD, the FD starts to behave like this.

So if you boot from the HD then it defaults to trying to format to 360k? If you boot from the FD, does format default to 1.44? I think that the first thing format does is write track 0 with appropriate headers, then try to read it back, and it's failing. I also think that it gets the default size from the BIOS, not from trying to read the existing track 0 (if I format an already formatted DD disk, then it'll try to format it as HD unless I specify otherwise). So maybe the FDC isn't being set up correctly when booting from the HD. No idea what would cause that.

I'm sure you'll have this right, but is the drive plugged in after the twist in the floppy cable?

What happenes when you remove the EISA controller and connect both IDE and Floppy to the multi-IO?
I would also check the jumpering of the multi-IO carefully.
Did you configure the EISA controller correctly with the eisa.cfg utility? If so, you need to make sure that the IO-and memory-ranges and IRQ that the utility has given the EISA controller are not conflicting with any ISA manually configured ISA cards.

Check your hard drive's CONFIG.SYS for a DRIVPARM statement. That directive is used to make DOS override the BIOS parameters for a specific floppy drive

Bancho wrote on 2021-04-24, 10:52:

If i try to format a floppy when booted from the HD and using the format command this happens. Its like its reading the disks in the wrong format. But the BIOS is set correctly (3.5 1.44mb) This behaviour is the same when using either controllers.

This looks very much like your BIOS "forgot" that the CMOS says 1.44MB. Maybe some expansion card is incompatible with the mainboard BIOS and overwrites the BIOS variable where the floppy parameters are stored. In your computer, the prime suspect is the DataCare/Tekram DC-620 controller. Obviously, your Controller is based on the first generation of the DataCare design, which I don't have any in-depth experience with. The second generation of DataCare (now called Tekram) controllers allow to choose between "mainboard IDE BIOS" or "enhanced controller IDE BIOS" in their setup. If your controller allows it, try disabling the enhanced IDE BIOS in the DataCare controller setup, or try whether the problems disappear when you use the IDE port of the ISA I/O card.

So i've done some more testing.

But first, this is the options in the BIOS for the EISA Controller.

So, I have another Winbond I/O card. This time I removed the EISA and just used this Winbond controller for HD and FD. Exact Same behaviour. I'm baffled. DOS is fresh install, no changes what so ever. I checked Config.sys but could not see DRIVPARM entry maxtherabbit mentioned.

Well in that case I suggest you add a line reading:

DRIVPARM=/D:0 /F:7

To your config.sys. This will force DOS to treat the drive as a 1.44MB regardless of what it thinks the BIOS equipment list says.

Have you done the initial EISA setup for this mainboard using the EISA utility, installed the .cfg / .ovl files for this mainboard? Maybe there is some old configuration still stored in the DALLAS NVRAM. Some mainbords demand even regular ISA cards to be configured with the EISA utility. After changing or reseating EISA cards, this utility needs to be run everytime.
Just to make sure, the mainboard setup is clean.

majestyk wrote on 2021-04-24, 15:36:

Have you done the initial EISA setup for this mainboard using the EISA utility, installed the .cfg / .ovl files for this mainboard? Maybe there is some old configuration still stored in the DALLAS NVRAM. Some mainbords demand even regular ISA cards to be configured with the EISA utility. After changing or reseating EISA cards, this utility needs to be run everytime.
Just to make sure, the mainboard setup is clean.

This is the only thing I haven't done yet. I did buy the motherboard and eisa card from the same seller. I have the config disk but its bad and I'm not sure where to retrieve the exact utility and files from. This is my first experience with EISA! The system actually works. So I can install DOS from the floppy disks, I've got the cd rom working off a SB16 card and its got a CL VL vga card which is detected correctly. the IDE Controller works fine and detects the HD and boots fine.

As I say, what I can't understand is, if I boot from a floppy, it acts normal. I was able to load the Turtle Beach Maui Utility from the floppy disk and play Descent on the system, by booting from the floppy disk and the accessing the C drive.

maxtherabbit wrote on 2021-04-24, 15:35:

Well in that case I suggest you add a line reading:

DRIVPARM=/D:0 /F:7

To your config.sys. This will force DOS to treat the drive as a 1.44MB regardless of what it thinks the BIOS equipment list says.

maxtherabbit.. your suggestion worked! I've never had to do this before on a system, floppy drives have normally worked without question! I'm now able to read from the disk!

What would cause this behaviour? If it can boot directly.. that would suggest the BIOS is correct? After installing DOS (from floppies on the same drive) it point blank refuses. As i say, this was a brand new DOS install. No changes to anything.

Thanks for all the help and advise given in this thread. Happy to report everything is working fine now. I've installed Win 3.11 and the sound cards now (Awe32 & Maui). All working nicely.