Using Int 25H with partitions > 32M 
Author Message
 Using Int 25H with partitions > 32M

Problem: New to assembly programming and I'm attempting to do an absolute
disk read for a hard drive >32M and I'm confused as to how to properly
load the registers before calling the interrupt. I should add that I'm
having no problem if the partition is <32M (like floppies).

Facts bearing on problem: I'm using "PC Interrupts" by Brown & Kyle, page
8-95, First Edition. In it, it states that:

                                al = Drive no
                                cx = 0ffffh
                             ds:bx -> disk read packet

The disk read packet contains (according to table 8-82):

                            offset   size   description
                             00h    dword   sector number
                             04h    word    number of sectors to read
                             06h    dword   transfer address

and that is all it says about it.

Now I'm confused because the offset addresses appear to be incorrect (if
the "sector number" starts at 00h, should not the "number of sectors read"
start at 09h?). Second, I can't quite figure out what to put into bx or if
I still need to load the logical sector number into dx. I'm even more
confused because preparing the registers when the partition<32M is so
straight forward.

If some one would be kind enough to respond with info as to what to load
the registers with, I would really appreciate it. Note my address below.



           Never appeal to a man's "better-nature". He may not have one.
                Invoking his self-interest gives you more leverage.
                                                  - L. Long


Mon, 14 Feb 2000 03:00:00 GMT  
 Using Int 25H with partitions > 32M

[snipped 80x86 asm problem]

You need to post your questions to comp.lang.asm.x86.

You might get your answer here, but this newsgroup is for IBM mainframe
assembler language. Entirely different machines.


Mon, 14 Feb 2000 03:00:00 GMT  
 [ 2 post ] 

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