Re: Disk ][ vs Unidisk vs Duodisk vs //c external disk

[Bill Shuff <bill2060@cris.com>]

Tim Shoppa wrote:
> 
> Starting 1979 or so the only Apple II disk drives I had ever used
> were Disk ]['s on ]['s, ][+'s, and //e's.  I've recently begun
> running across quite a few drives with 19-pin D connectors:
> Unidisks, Duodisks, and //c external disks.  I've also begun
> entertaining the thought of buying a IIgs.  A few questions:
> 
> 1.  Am I correct in assuming that I can just daisy-chain these
> drives onto each other?
> 
> 2.  I understand a IIgs can control up to four drives in a
> daisy-chain.  Is this also true for the "Duodisk" controllers
> I've been seeing in //e's?  Or are these limited to a total
> of two drives (a single Duodisk?)
> 
> 3.  What is the wiring of the 19-pin connector?  How is
> drive select handled?  I understand the 20-pin Disk ][ cabling
> quite well, but don't see how it is easily extended to include
> 4 drive selects.
> 
> Thanks!
> Tim. (shoppa@triumf.ca)

By the way, it is possible to daisy chain one or two Disk II's any place
a DB-19 5.25 drive will work.  I have been making adaptors and
replacement cables that considerably extend the utility of the Disk II
by allowing it to become part of a daisy chain.

Bill Shuff