25 May
2007
25 May
'07
3:31 p.m.
On 25 May 2007 at 7:37, mbbrutman-cctalk at brutman.com wrote:
Normally I see these machines with two internal
floppies, and nothing
else. On the 5160 I have here in the office I am about to add an
external floppy using the external connector on the floppy controller;
the machine has a single drive installed internally now. How does the
BIOS handle this situation? If I tell it that there are 2 drives will
it try to figure out that one is internal and one is external? Do I
need device driver help, or is this something the BIOS tries to
handle? Is there something on the controller card I am supposed to do
to tell it how the drives are connected/organized?
No, the 5150 is somewhat simple-minded when it comes to floppies.
There's nothing in the BIOS RAM area that identifies the exact
position of drives installed. If you have only a single internal
drive installed and one external drive, the BIOS will expect that
you've specified 3 drives and you will receive a non-fatal error 601
(IIRC) when it comes to look for drive B:.
If you're running a version of DOS later than about 3.2, you can get
around this problem by setting the mobo switches to the number of
internal drives you have, then use DRIVER.SYS to specify the external
drives.
A similar situation obtains for hard disks on the XT--the controller
expects that you will have a drive 0 installed if you have a drive 1
installed--even though electrically, there's no requirement for it--
only that there should be proper termination on whatever the last
drive on the cable is.
Cheers,
Chuck