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hi everybody,

I want to know, what's the best way to determinate which IDE Devices are present and which aren't. I want to do it the hard way by using ports. I'm not new to this, because I've already read sectors & device id information via ports, but now it would be nice if my os could find the existing ide devices.

I hope you can help me!
Thanks!

(I'm sorry for my bad English, but I hope you can understand what I would like to know)

First you would do this.
mov byte [command],0ECh
lable1:
mov word [Port],1F0h
mov byte  [Drive],0
call IdentifyDrive                   ; this is your proc for 12byte command's
mov byte  [Drive],10h
call IdentifyDrive
mov word [Port],170h
mov byte [Drive],0
call IdentifyDrive
mov byte [Drive],10h
cmp byte[command],0A1h
je endofprogram
mov byte [command],0A1h
jmp lable1

endofprogram:

At the end of the "IdentifyDrive" proc you test the comnand number if its "0ECh" its a harddrive,if its 0A1h it's a cd/dvd drive,if there is nothing on the port etc it should have a time out error and return.

This code has not been tested so may need moding.

ASHLEY4.

I recently did this for my thesis project.  Depending on how in depth you want it to be, you can scan the pci bus looking for ide controllers.  Once you have a list of these you may probe them with a degree of confidence.  If you just probe the standard ide ports 0x1f0h and 0x170 you only have access to the 4 drives that connect to it, not possible additional ata addon cards eg a promise expansion card.  

Working with the standard interface will work however it doesn't allow you to enable advanced features like UDMA33/66/100/XXX. For these you must code a specific driver however their function are basically the same, with a few hardware differences.

I have found that it is easier to talk to the disk using PIO than DMA however, if you os is multi-tasking then DMA is really the only way to go, thats just my opinion though.


cheers

orb

hi everybody,

Thank you for your great help!
But I've another problem right now: My os boots up and detect all connected ide devices correctly. But after that the status port (0x1F7) contains the value 0x00 (without emulator) and some usefull value (ready&seek complete) with VMware. I think I've to initialize my harddisk & controller first, but I don't know how.

I hope you can help me again