Yes; here's what ndisasm has to say about nofloppy.com:

100000000  B0F7              mov al,0xf7
200000002  E665              out 0x65,al
300000004  CD20              int 0x20

If you can just add b0/f7/e6/65 somewhere in the ROM where it will be executed during POST it will probably do what you want. If you want to be anal about it, you should save/restore the previous value of ax by a "push ax" before and a "pop ax" after the above sequence.

1push ax
2mov al,0xf7
3out 0x65,al
4pop ax

...which run through the assembler give 50/b0/f7/e6/65/58

Excellent. I assumed there would be a disassembler out there for things like this, but seeing as how it was only a few bytes I figured I might learn something if I did it by hand.

I'm going to stick that into my XT-IDE bios somewhere and see what happens...

Nasm/Ndisasm are your friends
http://www.nasm.us/

Please post back your results, it will be instructive.

I'll test out disabling the floppy tonight, but I"m still waiting on my high-density floppy controller to arrive.

I'm pretty confident that it will work just peachy though...

Since you're bent towards sticking things in the XT-IDE ROM, did you know that you don't need a high-density floppy controller but rather just the BIOS from one, in conjunction with a regular ISA multi-IO card? Yes, a regular 16-bit ISA IO card will work in a 8-bit slot if you provide it with the appropriate firmware. See my post on VCF (I am jh1523 there) http://www.vcfed.org/forum/showthread.php?484 … 6253#post376253 and the remainder of the thread too.

I have come across that thread before. I'm planning on putting together one of Sergey's combination FDC/USB 8-bit cards and loading both xt-ide and fdc bios into the XT-IDE's 32kb rom.

I'm also going to explore modifying a Tandy 1000SL I have laying around for high-density floppy support.

According to the FAQ, the 1000SL/TL has a controller capable of using 1.44mb drives but:

"In the SL and TL, the data separator is capable of running at 500k bps, but the data rate pin is hard-wired to 250k and the drive speed pin on the floppy cable is not connected."

Maybe it's as easy as jumpering a few places on the motherboard and using Sergey's floppy bios...

I have some positive results to report.

I was able to compile xt-ide firmware with the added instructions to disable the tandy fdc.

It boots, and the floppy controller is MOST CERTAINLY disabled.

Unfortunately I can't test it out until I get my high density controller in the mail Monday.

I'm still highly optimistic this will let me boot from that new controller though...

Everything worked perfectly. I can boot from a high-density floppy drive on my 1000TL (and presumably 1000SL/TX) using the high-density floppy bios, custom XT-IDE bios, and Sergey's FDC.

Good job.

Is it possible to insert an High Density Floppy BIOS code into an XT Philips NMS9100 machine? The machine it self is an 8086@8MHz with an Single Density Floppy Controller.

Stojke wrote:

Is it possible to insert an High Density Floppy BIOS code into an XT Philips NMS9100 machine? The machine it self is an 8086@8MHz with an Single Density Floppy Controller.

If you can disable the existing floppy controller it might be possible to add an aftermarket floppy controller like Sergey's card.

keenerb wrote:

Everything worked perfectly. I can boot from a high-density floppy drive on my 1000TL (and presumably 1000SL/TX) using the high-density floppy bios, custom XT-IDE bios, and Sergey's FDC.

Very cool. Would like to do this for my TL/2 but unfortunately I don't have a free slot for the floppy controller.

bjt wrote:

keenerb wrote:

Everything worked perfectly. I can boot from a high-density floppy drive on my 1000TL (and presumably 1000SL/TX) using the high-density floppy bios, custom XT-IDE bios, and Sergey's FDC.

Very cool. Would like to do this for my TL/2 but unfortunately I don't have a free slot for the floppy controller.

TL/2 only has four ISA slots, doesn't it?

That is rather limiting.

keenerb wrote:

Stojke wrote:

Is it possible to insert an High Density Floppy BIOS code into an XT Philips NMS9100 machine? The machine it self is an 8086@8MHz with an Single Density Floppy Controller.

If you can disable the existing floppy controller it might be possible to add an aftermarket floppy controller like Sergey's card.

Dipswitches only define hard disk controllers, but I heard that an FDC bios can be updated for DD disks.

Yep it loses a slot for the (useless) built-in IDE controller.
My slots are used up by a XT-IDE, SB16, EGA card and 2MB EMS.

bjt wrote:

Yep it loses a slot for the (useless) built-in IDE controller.
My slots are used up by a XT-IDE, SB16, EGA card and 2MB EMS.

I picked up a passive isa backplane on ebay for pretty cheap. I am going to see if I can use it as a bus expander for me 1000to.

Bringing this thread back from the dead just to say i have successfully tested a different approach to this.

If you have a socketed floppy controller on your 1000SL or TL you just simply lift it up from its socket. From that moment on there's no longer anything hogging the resources at the standard floppy ports and you can just add a high density floppy controller without any issues. Make sure you disable the extra COM and parallel ports you won't need.

Of course this also requires that you add floppy BIOS extensions, just like with keenerb's approach.