paul@crash.cts.com (Paul Palacios) (11/29/87)
I am looking for any information about the internals of DOS in general
(version 3.xx). I am writing some software that effectively runs
background and need to perform DOS function calls for file i/o. I must
use the DOS calls instead of the BIOS so that the same code will also run
on several LANs.
The actual idea is to suspend new calls to DOS by the foreground proc and issue
my own and then resume the foreground proc. This all might sound simple, but
some DOS calls use other DOS functions via int 21h rather than using the
address of the functions it needs. Because of this, to simply trap the
entrance to a DOS function request will not suffice, since it may be a function
called by DOS itself.
There is a flag set in DOS that is reset when it is not safe to use DOS calls,
and even an undocumented DOS function to get a pointer to it, but that still
doesn't work well to suspend it.
If I am incorrect in any of this, this may be part of my problem; so let me
know. I, however, have believed this to be true from past experience.
Please post, or send mail to me directly if you have any information
what-so-ever that may help. If there is another method other than trying to
suspend DOS that might work better, please let me know.
Any information regarding this will be greatly appreciated.
- paul