[comp.sys.ibm.pc.hardware] DRIVER.SYS vs. DRIVPARM

wales@valeria.cs.ucla.edu (Rich Wales) (09/03/90)

In article <4243@trantor.harris-atd.com>
sonny@trantor.harris-atd.com (Bob Davis) writes:

	While I am at this, I'll ask about confusion I have about
	this bringing up 3.5 inch floppies on a DOS 3.3 system:

	WHAT IS THE DIFFERENCE BETWEEN THE drivparm COMMAND AND
	THE device=driver.sys ..... APPROACH TO LETTING THE SYSTEM
	KNOW ABOUT 3.5 INCH FLOPPIES?

Using DRIVPARM=... takes a little less RAM than DEVICE=DRIVER.SYS does.
DRIVPARM= sticks the parameters you specify into a table which is used
by DOS's builtin generic driver.  DEVICE=DRIVER.SYS loads a separate
copy of the generic driver (with the specified parameters).

If you use DEVICE=DRIVER.SYS, there will also be a difference in the
drive ID letter assigned to the floppy drive in question.  My recollec-
tion from using this approach was that I had to call my second floppy
drive (a 3.5"/1.44Mb unit) drive "D" instead of "B".  Actually, I think
the same unit responded to both "B" and "D" -- though the parameters
were different for the two designations.

Given a choice, I would recommend using DRIVPARM= instead of DRIVER.SYS.

One problem with DRIVPARM= is that the original release of MS-DOS 3.3
had a bug in the CONFIG.SYS command parsing code.  Although DRIVPARM=
was documented, and the code to handle it was there, it didn't work.

There are two solutions to this DRIVPARM= parsing problem:

(1) Get MS-DOS 3.30A.  If your MS-DOS 3.3 is the "generic" version from
    Microsoft (i.e., not modified by the vendor for your clone), you can
    call Microsoft technical support and get the replacement disks for
    free.  Otherwise, you'll have to bring the issue up with the people
    who made your clone -- and hope they (a) know about 3.30A and (b)
    have bothered to get it.

(2) Include one or more "control-A" characters immediately after the
    equals sign in your "DRIVPARM=" line.  This will reportedly sidestep
    the parsing bug.

Some vendors may have fixed the DRIVPARM= bug on their own -- and/or
used 3.30A while still calling it 3.3.  So, before you do anything else,
try DRIVPARM= without the "control-A" hack and see if it works for you.

--
-- Rich Wales <wales@CS.UCLA.EDU> // UCLA Computer Science Department
   3531 Boelter Hall // Los Angeles, CA 90024-1596 // +1 (213) 825-5683
   "You must not drink the tea.  It is deadly to humans."