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From: mcs@fps.com (Mike Sanfratello)
Newsgroups: comp.unix.xenix.sco
Subject: Re: tape drive errors, is there a listing
Keywords: tape drive error exec ready rdy failed to go active qic-02 ct cmd tecmar 6157 mca xenix unix
Message-ID: <17587@celit.fps.com>
Date: 9 May 91 20:48:30 GMT
References: <892@wyn386.mi.org> <16615@scorn.sco.COM>
Sender: daemon@fps.com
Reply-To: mcs@fps.com (Mike Sanfratello)
Organization: FPS Computing
Lines: 28

In article <16615@scorn.sco.COM> paulz@sco.COM (W. Paul Zola) writes:
>
>PROBLEM:    The message "ct cmd error (%d,%b)", where %d is 0, 1 or 2 
>	    and %b is a a hexadecimal number, appears quite frequently 
>	    when the tape drive is in use.
>
>CAUSE:      The interrupt handler contains a loop which polls the tape, 
>	    waiting for the status to say Ready or Exception.  If neither 
>	    bit gets set in a reasonable amount of time, the loop runs out 
>	    and the status read may not be accurate.  As machines have become 
>	    faster, this time period may have become too short for some 
>	    configurations, and hence the error messages.
                                                                            
This is very poor driver construction; blind spin loops should be outlawed!
I've seen the ct driver source, and I'm sure you'll agree with me that this
is a very poor example of a tape driver and should be redone.