PURPOSE
 
This document is a description of the hook-ups and modifications that
I found necessary in adding a 3.5 inch double sided drive to my Atari
520. It is intended solely as a guide to anyone who is interested in
saving a few dollars by using an "industry standard" drive in place of
the Atari SF314.
 
WARNING
 
This installation seems to function properly for my system, but I
cannot guarantee anything. Also, the only way that a saving will result
is if a suitable power supply is already available, or can be obtained
at a very low price.
 
REQUIREMENTS
 
1        3.5" Double Sided Drive w/ Installation kit @ $130
         (The Unit I used was a Toshiba(tm) ND-352 which came with a
         multi-purpose mounting kit. BE SURE that the unit is XT
         compatible!!(720K))
 
1        34 pin Card Edge Connector                  @ $  3
 
1        Standard Atari(tm) 3.5 in Disk Drive Cable  @ $  8
 
<additional info given on cases and power supplies>
 
PRODECURE
 
There are two ways to proceed with this project depending on whether
you want the new drive to be A or B. The Drive B method is the simpler,
so I will start with it.
 
_____ 1.  Cut the Standard Drive Cable in half 
_____ 2.  Strip back about 2" of the outer insulation from the cable.
          Do Not cut off the shield wire (a layer of wire woven around
          the multiple conductors in the cable). Carefully unweave the
          shield, and twist it to form a wire of its own.
_____ 3.  Since the 34 pin connector that I used was designed for
          ribbon cable, some ingenuity is required here. 
 
The Connections Follow:
 
(NOTE: the colors mentioned are for an Atari Cable. You should check
if you are using an After Market Cable.)
 
             34 pin conn.   Atari conn.   Signal     Color
                 2              *         media chng
                 4             N/A        in use
                 6             N/A        d4 sel
                 8              4         index      yellow
                10              5         d0 sel     green
                12              6         d1 sel     violet
                14             N/A        d2 sel
                16              8         motor on   brown
                18              9         direction  orange
                20             10         step       grey
                22             11         wrt data   pink
                24             12         wrt gate   lt. blue
                26             13         track 0    lt. brown
                28             14         wrt prot   lt. green
                30              1         read dacrosoft (Presentation Manager), Carnegie-Mellon University, and oddly,
even Sun Microsystems' Open Look interface.  Afterwards, it will consider
whether it should base its standard on an upcoming release of AIX, IBM's
version of Unix, or some other Unix dialect, like Berkeley Unix.


      The OSF estimates that it will have its alternate Unix standard
complete by early 1990, while AT&T is saying that Unix Version 5.4 will be
shipping by Fall 1989.  This gives AT&T (if they deliver on time) at
least eight months in which to retake the Unix market.  AT&T has already
begun to do this by rallying support for Open Look, as toolkits for this
graphical interface will be available in the First Quarter of 1989.  Then,
the question becomes if AT&T and Sun alone should be able to dominate the
course of Unix, as IBM/Microsoft have the course of MS-DOS, without the
help of other Unix licensees, or if a group of Unix vendors will be able
to muster great support for their Unix without AT&T.


      With the advent of OS/2, the computer industry finally began to take
a look at multitasking operating systems, and noticed Unix, with its
powerful capabilities.  As such, Unix has become very important, having
the potential of eventually guiding the microcomputer industry into the
21st Century.  Now the issue is if Unix not only can overcome the MS-DOS,
Macintosh, and OS/2 alternatives, but can withstand the dissention within
its internal ranks to establish a standard worthy of such a feat....


But ponder, if you will, on these two questions:

1)  What exactly are the capabilities of the Atari ST and Amiga's bus
architectures?

2)  What steps do users take to replace or supplement their systems
when they become obsolete, orphaned, or don't have enough software?

                               ---=====***=====---
