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From: rick@NRC.COM (Rick Wagner)
Newsgroups: comp.sys.ibm.pc
Subject: Re: Disk Driver Formatting in
Message-ID: <364@nrcvax.NRC.COM>
Date: 2 Oct 89 18:52:46 GMT
References: <799@hemingway.WEITEK.COM>
Reply-To: rick@nrcvax.UUCP (Rick Wagner)
Organization: Network Research Corp., Oxnard CA
Lines: 30

In article <799@hemingway.WEITEK.COM> robert@hemingway.WEITEK.COM (Robert Plamondon) writes:
>>>    I have a 3.5 " disk drive that can read 720K and 1.44M diskettes. It
>>>is installed as the drive A: on my system. When I start the system, the 
>>>first diskette I read in this drive via aDIR command will have the 
>>>proper directory, but any other diskette read later will give me the 
>>>SAME directory as the first one, even if it's another. It seems that DOS
>>>cannot re-read the FAT and DIR sectors. The diskettes I tried are both 
>>>formatted in DOS 3.3 and DOS 4.01. . . . .
>
>DOS (or the BIOS) expects the diskette drives to have a "READY" signal
>that indicates whether the diskette has been replaced.  If it expects
>this signal from a drive that doesn't provide it, it thinks that it
>still has the original disk in its drive, and uses the copy of the
>directory and FAT in RAM, rather than reading it from the floppy
>again.

Most of the 3.5" drives do supply a "disk change" line.  What I have
found is alot of the drives are shipped with this option disabled.
The drives I have seen (Teacs, I think), have a jumper on the board
where the ribbon cable connects to the drive, which enables this
signal.  Check your drive documents, and see if this is the case with
your drive.

	-rick
-- 
===============================================================================
Rick Wagner						Network Research Corp.
rick@nrc.com	rick@nrcvax.UUCP			2380 North Rose Ave.
(805) 485-2700	FAX: (805) 485-8204			Oxnard, CA 93030
Don't hate yourself in the morning, sleep 'till noon.