Sector reading in ASM with C

[Jonny K]

Hi,

I'm using inline ASM in C, and I'm wondering how I can get the variable 'test' to contain a whole sector from a floppy disk.

Any ideas?


Jonny

[Da_Maestro]

1. Make 'test' an array of 512 bytes.
2. Load the sector into the address of 'test'
3. Voila


If you want the memory address to be mapped to the sector on the disk and updated with reads/writes...that's way too complicated for your every day homebrew os :-p

[Jonny K]

Thanks, but umm, I need to know how to actually read a sector


Jonny

[Da_Maestro]

Ok well that's a different question alltogether.

It depends on whether you are running in real-mode or protected-mode.

In real mode this is as easy as using the BIOS. However when you do this you loose the ability to switch to a different task while the disk is being read.

For this and for protected-mode it is recommended that you access the disk hardware directly. There is plenty of sample code available, and intels documentation on their floppy disk controller is pretty good.

I can't refer you to any links...I'm posting from work

Anyone else know anywhere you can find manuals/references/code?

Adam

[deadmutex]

try http://www.osdever.net/cottontail/
it has almost everything one would need.