VOGONS


XTIDE Can't Boot Floppy

Topic actions

First post, by LChackr

User metadata
Rank Newbie
Rank
Newbie

I have a ROM card in my 486DLC PC with XTIDE on it. I have a working bootable floppy in Drive A. The system boots to that floppy if XTIDE is not enabled. If I enable XTIDE and try to get it to boot from the floppy it tries to read the disk (drive motor/heads engage) but it says Non-System Disk.

Has anyone run into this before? Why would the system be unable to boot from a floppy only when XTIDE is active?

Thanks!

Reply 1 of 3, by LChackr

User metadata
Rank Newbie
Rank
Newbie

UPDATE: It boots if I disable the internal 486DLC cache. 🤦‍♂️

I guess I need to report a bug?

Reply 2 of 3, by Jo22

User metadata
Rank l33t++
Rank
l33t++
LChackr wrote on 2023-09-05, 21:13:

UPDATE: It boots if I disable the internal 486DLC cache. 🤦‍♂️

I guess I need to report a bug?

Maybe. 🤷‍♂️

I assume it somehow has to do with DMA and the caching of certain memory regions.
Floppy i/o uses DMA controller.

Thing is, there are several ways of controlling (flushing) the 486DLC cache on a 386 motherboard.
Some motherboards are 486DLC aware, even have support in chipset and BIOS.
They don't need a DOS utility to activate the 486DLC cache.

On the other hand, those are likely 486 era chipsets and support a real 486, as well,
so there's not much of a reason to use them with a 486DLC amd not a full 486.

By contrast, vintage 386 motherboards can be given new life by installing a 386DX40 or a 486DLC.
And those usually require certain hacks to make the 486DLC cache work.

Anyway, I'm just a layman here.
Maybe there are certain settings to try or alternate 486DLC DOS utilities that will fix the issue? 🤷‍♂️

Edit: As a workaround, you could try to not enable 486DLC cache in BIOS and instead use a DOS utility.
It's no real solution to the issue, of course, but the right DOS utility may support the same method of cache control as BIOS.
If the chipset/socket has the appropriate control lines, I mean. The official Cyrix utilities are maybe a good start.

"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel

//My video channel//

Reply 3 of 3, by LChackr

User metadata
Rank Newbie
Rank
Newbie
Jo22 wrote on 2023-09-05, 21:28:

As a workaround, you could try to not enable 486DLC cache in BIOS and instead use a DOS utility.
It's no real solution to the issue, of course, but the right DOS utility may support the same method of cache control as BIOS.
If the chipset/socket has the appropriate control lines, I mean. The official Cyrix utilities are maybe a good start.

Yeah, this is a Cyrix-aware motherboard and even directly mentions Cyrix cache by name in BIOS. This is also a late-model 386 board with a combination 386/486 chipset. I suppose I can disable the cache in BIOS and enable with a utility. Thanks!