Accesing floppy drive in protected mode

davidv1992 · Post by **davidv1992** » Thu Jul 05, 2007 9:07 am

I wan't to learn how to access my floppy drive while running in protected mode, but i can't get any clue from the wiki article about this. Can somebody help me by pushing me in the right direction.

hailstorm · Post by **hailstorm** » Thu Jul 05, 2007 10:30 am

You could search this forum, I guess this subject has been discussed a lot.
You have three options:

Switch back to real mode to execute a bios call
Access the hardware directly.
I could say; use vm86 task, but hey, that requires a lot of programming to, and you still have to go to real mode to execute a bios call or access hardware directly, I believe.

davidv1992 · Post by **davidv1992** » Thu Jul 05, 2007 11:17 am

i've tried, and i couldn't found anything.

Alboin · Post by **Alboin** » Thu Jul 05, 2007 11:24 am

davidv1992 wrote:i've tried, and i couldn't found anything.

At the end of the wiki article there are links. Those are probably what you're looking for.

This one isn't bad...

Ninjarider · Post by **Ninjarider** » Thu Jul 05, 2007 3:00 pm

ralph brown should have a list of hardware in/outs. yours options are either return to real or direct access.

in the odd event that this is on a windows machine. theres a 21h interrupt.

earlz · Post by **earlz** » Thu Jul 05, 2007 5:54 pm

there really should be a better FDD tutorial...and one with working FDD code at the end, or at least some kinda psuedo code...

Alboin · Post by **Alboin** » Thu Jul 05, 2007 6:06 pm

hckr83 wrote:there really should be a better FDD tutorial...and one with working FDD code at the end, or at least some kinda psuedo code...

Write one.

earlz · Post by **earlz** » Thu Jul 05, 2007 6:48 pm

I'd have to learn how to do floppy code first!

jnc100 · Post by **jnc100** » Fri Jul 06, 2007 3:34 am

Try reading the datasheets at http://www.datasheetarchive.com/search. ... sType=part.

Basically, you write to various ports to select the command you want to execute, run it then wait for an interrupt. You can use pio or dma for data transfers (dma is probably better).

Regards,
John

Dex · Post by **Dex** » Fri Jul 06, 2007 3:37 am

Never fear, I is here:

Here is the pmode floppy driver from DexOS, it is well commented and follows the pedo code in the intel floppy controler PDF.

Floppy code:
http://www.dex4u.com/tuts/FloppyDriver.zip

Intel PDF:
http://bos.asmhackers.net/docs/floppy/d ... asheet.pdf

PS: I am doing a Dev Mag, anyone want to write a floppy tut is most welcome.
Sample:
http://www.dex4u.com/DexMag/DexMag1-0.htm