Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!uwm.edu!linac!midway!gsbsun!valley From: valley@gsbsun.uchicago.edu (Doug Dougherty) Newsgroups: comp.binaries.ibm.pc.d Subject: Re: help for PC problems! Message-ID: <1991Jun29.145007.19607@midway.uchicago.edu> Date: 29 Jun 91 14:50:07 GMT References: <28693cdf.206b@polyslo.CalPoly.EDU> Sender: news@midway.uchicago.edu (NewsMistress) Distribution: usa Organization: University of Chicago Lines: 29 cwinemil@keys.lonestar.org (Chris Winemiller) writes: >gyao@polyslo.CalPoly.EDU (Ginlom Bob Yao) writes: >> When i insert a floppy in drive A and type dir, it always comes out >> the former contents (which is the first one after reboot. >> It doesn't matter how many times i change other floppys later.) I can use >Bob, > There is a mechanism in your floppy drive which detects "change of >media"; i.e., it signals when a floppy has been removed/inserted. DOS >uses this info; it stores your floppy's "directory" info in memory and >uses _that_ instead of reading your floppy each time. When the floppy >is changed out for another, DOS detects it and then reads the disk >itself and stores its info. Now, if the "change of media" signal from >the drive is broke, it may think that there's "always" a floppy >inserted and never changed out! This happened to me recently. You can Interestingly enough, this happens to me frequently (but not always), when I switch diskettes *if* I do the switch quickly. If I wait a few seconds between removing the first and inserting the next, it will be OK. There is a statement in one of the DOS programming manuals to the effect that "it is impossible to switch a disk in less than two seconds" and DOS uses this fact to determine whether the diskette has been changed. I wonder if I'm just fast, or if some drives/versions of DOS stretch this two seconds out a bit. -- (Another fine mess brought to you by valley@gsbsun.uchicago.edu)