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From: joels@tekred.UUCP (Joel Swank)
Newsgroups: net.micro.cbm
Subject: Re: 2 c64s sharing a 1541 drive: questio
Message-ID: <451@tekred.UUCP>
Date: Wed, 19-Feb-86 18:21:58 EST
Article-I.D.: tekred.451
Posted: Wed Feb 19 18:21:58 1986
Date-Received: Fri, 21-Feb-86 07:36:00 EST
References: <8900001@umn-cs.UUCP>
Organization: Tektronix, Beaverton OR
Lines: 28

> Can one 1541 disk drive be shared between two C64s ?
> 
> The big questions: 
> 1. Can the disk drive be shared? i.e. can I plug one C64
>    into one of the ports on the back of the 1541, and the other C64 into
>    the other port on the 1541? 
 NO
> 2. I suppose this is a funny form of daisy-chaining; will any of the 
>    devices involved get screwed up?
  Yes. The serial bus can have only one controller.
> 3. Can I define the drive to be device 8 to both C64s? Device 8 to on C64,
>    device 9 to the other?  
No, the disk can have only one device number at a time.
> 
> Thanks, Jay
> 
> davis%umn-cs.csnet@csnet-relay

What you really need is a switch. I built one for my VIC and C64. There
was an automatic switch available (called VIC-switch I think). It worked
well and handled up to 6 computers connected to a disk. Cost $150. I
don't know if it's still available.
  Get a 4 pole double throw switch. Wire it in a box and connect the
SRQ, ATN, CLK and DATA lines to it. Make GND common. Do Not connect
RESET (unless you want all three devices to always reset together).

Joel Swank
Tektronix, Redmond, Oregon