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From: poffen@sj.ate.slb.com (Russ Poffenberger)
Newsgroups: comp.sys.ibm.pc.hardware,comp.periphs
Subject: Re: Problem getting floppy drive to work with DTC 3280A SCSI card
Message-ID: <1990Oct18.152711.18904@sj.ate.slb.com>
Date: 18 Oct 90 15:27:11 GMT
References: <1990Oct17.165757.4274@polyof.poly.edu>
Reply-To: poffen@sj.ate.slb.com (Russ Poffenberger)
Organization: Schlumberger Technologies, San Jose, CA.
Lines: 51

In article <1990Oct17.165757.4274@polyof.poly.edu> ted@polyof.poly.edu (Theodore S. Kapela, staff) writes:
>I have a Data Technology Corporation 3280A SCSI host adapter w/floppy
>controller.  I have been trying to use it with my 5 1/4" and 3 1/2"
>drives (both high density).  When I first boot the machine and try to
>read a floppy, everything seems OK.  BUT, when I change the floppy and
>try to do a dir or chkdsk,  The drive does not really read the floppy.
>I turns the drive and access light on, but does not appear to read
>anything.  I get the same info (eg: directory listing) that I just had
>for the floppy that was in the drive last.  ALSO, I can not swith to
>another density media after first reading a disk.  If I read a high 
>density disk, that is all I can use the drive for.  If I read a 
>standard (double) density disk, that is all I can read afterwards.

The AT class machines introduced a tehcnique using a signal line on the floppy
drive to indicate that the drive door was opened. This line is supposed to be
a clue to DOS to re-read the disk since it may have been changed. Simple
commands like "dir" cahce the information in memory, and don't re-read the disk
for another "dir" operation if the drive door hasn't been opened.

It is possible that either the drive itself or the controller do not support
this feature.

>  
>If I try to format a disk, though, I can format either density just
>fine at any time.  I can then only read that density afterwards.
>   
>I tried using DOS's driver.sys to make another "virtual" drive.
>I used a: for the high density 5 1/4" drive and e: for the double
>density 5 1/4" drive.  They are both physically the same drive, 
>but I told DOS that their parameters are different.  Format recognizes
>the parameters and formats the disk appropriate for the drive, but the
>rest of DOS doesn't care.  I can read either density in either drive, 
>but then I have the same problem as above, only for both drives (if I
>read a 1.2M disk in a:, that is all I can read in i: also.)
>    
>The problem does not pertain strictly to DOS.  It happens in applications
>also (possibly because they use DOS calls for disk access).
>     
>The drives worked fine with another controller.  I had no problems 
>then.
>      
>If anybody else has had this problem or has any clue how to remedy the
>situation, I would greatly appreciate a reply.

Either it is a bad controller, or it simply doesn't support the door opened
feature. My suggestion is to get an Adaptec AHA1542 controller instead. :-|

Russ Poffenberger               DOMAIN: poffen@sj.ate.slb.com
Schlumberger Technologies       UUCP:   {uunet,decwrl,amdahl}!sjsca4!poffen
1601 Technology Drive		CIS:	72401,276
San Jose, Ca. 95110             (408)437-5254