arasmith@mathcs.emory.edu (David Arasmith) (09/13/90)
I have a question for those out there more knowledgable than myself.
I am trying to determine the number of logical hard drives on any garden
variety IBM PC or PS/2 from within Turbo C(++ v1.0). I cannot assume
that functions such as setdisk() will give reliable information.
What I need is a way to check a particular drive without encountering
the infamous Abort, Retry, Fail. Does someone out there know an easy
way to poke a drive (and determine if it is fixed or floppy) without
forcing a user to insert a floppy? (I'm not worried about a: & b: - it's
the d:'s e:'s and f:'s hanging off the back that concern me!)
Thanks a lot! Email is more likely to get to me (actually me to it).
--
David M. Arasmith | arasmith@mathcs.emory.edu Internet
Emory University | {sun!sunatl,gatech}!emory!arasmith UUCP
Dept of Math and CS |
Atlanta, GA 30322 | I should be working! Gee....I wonder what's on TV?PA163514@tecmtyvm.mty.itesm.mx (09/16/90)
Sorry, but I wrote Good, Luck.
phys169@canterbury.ac.nz (09/20/90)
In article <90257.135612PA163514@tecmtyvm.mty.itesm.mx>, PA163514@tecmtyvm.mty.itesm.mx writes: > Arasmith, > > TOPIC: How many disk drives are in your PC? > > These are the steps: : > 4. Get value in Port 60h ..etc... That isn't always going to solve the original problem, of finding the number of hard drives without waiting for a floppy, but it does find the number of diskettes from the dip switches on a PC okay, although int 11h would be much better, as far as compatibility is concerned, or even peeking at location 410h, i.e. NumberOfDiskettes:=(memw[$40:$10] and 1)*(1+(mem[$40:$10]and 3) shr 6). The number of *physical* hard drives can be found in most PC/XT/AT compatibles at byte 475h (mem[$40:$75] in Turbo Pascal), but that doesn't allow for logical drives, nor does using int 13h with AH=15h, DL=80h+each drive number to test. The "proper" method is to ask DOS via int 21h, AX=4408, and BL varying from 1 to the highest likely drive number (say 26); the result is: carry flag on means an invalid drive, otherwise AX=1 means a fixed disk - which might be a network drive, so you could test if bit 12 of DX is 0 (DOS call 4409h), if that is a possibility you need to check. Unfortunately, this requires DOS 3 or above. If you must use DOS 2, use the number at location 475h, rememberring the first hard drive letter will be "C" in DOS if you are on a PC, or higher on a PC/XT if the number of diskettes is >2, or lower if running on a DG10 with only one diskette drive (but who uses them nowadays??). Hope this helps, Mark Aitchison, Physics, University of Canterbury, New Zealand.