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Boot physical 3.5" floppies via emulated floppy image on CD

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buckchow

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Sep 2, 2016
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Hi all. I'm interested in finding a way around the increasingly limited floppy booting support in new computers. Alternatives to real floppy controllers seem to depend on there at least being BIOS support for floppy drives and/or ARMD (LS-120), but this support seems to be increasingly unreliable, broken, or absent in new motherboards. My understanding is that existing specialty devices such as KryoFlux and Catweasel can't be used to boot floppy disks, so another option is needed.

Making use of the El Torito specification for bootable CDs from 1994 sounds like the best option. El Torito includes support for 1.2MB, 1.44MB, and 2.88MB floppy disks via disk images on bootable CDs, and new motherboards continue to support floppy emulation for such bootable CDs. I'm interested in having a hardware interface that allows a floppy drive to be seen by the computer as a bootable CD-ROM. When sectors of the CD are read that contain the floppy image, reads from the physical floppy would occur.

I wouldn't be surprised if one or more clever people have already created interfaces like the one I'm thinking of, but so far I haven't found anything. Does anyone know of an existing or in-development interface like the one I described?

For anyone wondering, I'm only interested in solutions that include the use of physical floppy disks. Yes, I could just make bootable CDs using images of the floppy disks. I plan to do that also, but I very much prefer the full slow, noisy experience of floppy booting when running old software on new computers. :)

Thanks in advance for your help.
 
The problem is that CD boot images assume a uniform sector/density layout. While this may work for vanilla floppies, floppies with copy protection incorporated will fail, as there's no way to represent the information.
 
Chuck(G) said:
The problem is that CD boot images assume a uniform sector/density layout. While this may work for vanilla floppies, floppies with copy protection incorporated will fail, as there's no way to represent the information.
Click to expand...
As far as I know, none of my disks are copy protected. I definitely appreciate that there would be limits that would cause problems like what you described. I'm guessing that the lack of support for emulated 720KB floppy disks could be overcome in most cases by mapping the data into one of the larger support disk sizes. Some trickery would probably be needed to detect disk changes once the system has booted. Just getting a single "vanilla" 1.44MB floppy to boot and be accessible for normal use after booting would be great by itself though. Any added functionality beyond that would be a bonus.
 
Basically, it's a lame solution in that it doesn't truly emulate a floppy drive. How, for example, would you run IMD on the emulated floppy?

One might as well boot from a USB flash drive.
 
If all you are planning to use are 1.44MB and 720kB floppy disks, check to see if the system permits booting from USB floppy. Skip all the hoops.
 
krebizfan said:
If all you are planning to use are 1.44MB and 720kB floppy disks, check to see if the system permits booting from USB floppy. Skip all the hoops.
Click to expand...

Agreed, that's the way I've had to go with my modern PCs. Set the BIOS to boot from USB floppy or Removable Device before CD.

If your board doesn't even support USB floppies, try burning Plop Boot Manager to a CD, that program recognizes just about all attached media and will allow you to invoke it as bootable regardless of motherboard support.
 
The whole point though was to boot on real hardware.

Although, honestly, I am surprised the cheap Chinese bastards have not yet removed all traces of BIOS yet. Once that is gone, no more DOS, floppies, older Windows or anything that does not support EUFI.

They just need to make a new damn motherboard with A REAL FDC, support for 2 drives of any drive type with FM and 128-byte support, 2 built in serial, 1 parallel, PS/2 mouse, PS/2 keyboard, IDE, and throw in an ISA slot. :p
 
Chuck(G) said:
Basically, it's a lame solution in that it doesn't truly emulate a floppy drive. How, for example, would you run IMD on the emulated floppy?
Click to expand...
I really wasn't imagining needing to do that. At this time, my interest is in being able to boot from "vanilla" floppy disks, run programs, access files. Just basic stuff.

Fire-Flare said:
Set the BIOS to boot from USB floppy or Removable Device before CD.

If your board doesn't even support USB floppies, try burning Plop Boot Manager to a CD, that program recognizes just about all attached media and will allow you to invoke it as bootable regardless of motherboard support.
Click to expand...
I haven't had good results booting from USB floppy drives in the past. I will very gladly try Plop Boot Manager since I hadn't come across it before. It sounds very handy if it really works as described.

Doug G said:
if you're a linux user, apparently qemu can boot a floppy image file. http://unix.stackexchange.com/questions/276480/booting-a-raw-disk-image-in-qemu
Click to expand...
Chuck(G) said:
So can VirtualBox.
Click to expand...
ldkraemer said:
If you install DOSBOX, you can also boot floppy images inside DOSBOX.
Click to expand...
I appreciate these suggestions, but they all relate to booting floppy disk image files, not booting physical floppy disks.


Thank you all for the responses. :)
 
SomeGuy said:
They just need to make a new damn motherboard with A REAL FDC, support for 2 drives of any drive type with FM and 128-byte support, 2 built in serial, 1 parallel, PS/2 mouse, PS/2 keyboard, IDE, and throw in an ISA slot. :p
Click to expand...

Ditch the ISA slot and I'll buy two. I'm not giving up room for PCI slots for anything. :)
 
Actually, due to the orientation, the last slot location can be shared between and ISA and PCI. So once installed in an ATX case either an ISA or PCI card may be installed in the bottom/left most slot location. The last few boards with ISA and PCI did just that.

http://motherboard.cz/mb/abit/kt7a.htm
 
SomeGuy said:
Actually, due to the orientation, the last slot location can be shared between and ISA and PCI. So once installed in an ATX case either an ISA or PCI card may be installed in the bottom/left most slot location. The last few boards with ISA and PCI did just that.]
Click to expand...
Ah yes, I remember that now. It has definitely been a while. Good deal.

Stone said:
I've got two K7S5A boards with all that... and more. But they both need to be recapped.
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Well sure, there are old boards with the same or similar features. Two here are running right now and chugging along merrily, although one has already been recapped and the other has had some bulging caps for years. SomeGuy mentioned a new board which would be all kinds of fun. I'll just assume the upcoming Zen boards will include several models matching his specs until I'm (devastatingly) proven completely wrong. :)
 
You have to be careful with ISA/PCI combo boards much later than 440BX chpsets--quite often, they're only partially functional. For example, they don't support ISA DMA, or resources have been excluded, such as IRQ6 or DMA 2 (floppy resources). When I need a board with an ISA slot, 440BX will be about as late as I'll go.
 
Chuck(G) said:
You have to be careful with ISA/PCI combo boards much later than 440BX chpsets--quite often, they're only partially functional. For example, they don't support ISA DMA, or resources have been excluded, such as IRQ6 or DMA 2 (floppy resources). When I need a board with an ISA slot, 440BX will be about as late as I'll go.
Click to expand...

The industrial P4 boards with ISA can work, but are really expensive.
www.ebay.com/itm/281465938102 for example.
Watch out for the Supermicro P4SCA board, though.
There is no way to disable the on-board floppy controller, making it useless if you want
to use an Adaptec ISA card for floppy.
The main reason I use these is being able to boot from a thumb drive, which is handy for
shuttling data w/o the hassle of setting up a net connection.
The last imaging station I built uses an Intel D845GECL, but those mb are pretty much
impossible to find now.
 
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A used socket 478 board sans CPU and memory (2 DIMM slots only) for $170 and $25 shipping?

Whatta deal!

Some boards that hail back to the P1 era don't entirely remove the floppy controller from the manifest. So while DOS may boot up just fine with your Adaptec controller, OSes with explicit chipset support, such as XP may try to revert to the integrated controller.

I've found that a few of the despised Intel 820 chipset boards (think RDRAM) have very good floppy support, passing all of the floppy tests with flying colors. A P3 at 1GHz/133 isn't too shabby for most "tweener" applications.
 
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