[Coco] 3.5" drives

[Kevin Diggs]

H,

	I spent much of yesterday trying to get OS9 to
boot. To the casual observer I imagine this would have
resembled watching the 3 stooges try to get a cray running.
I had this thing scattered across the room. Turns out the
cable between the "HCA" and interface board was backwards.
Its a wonder I didn't blow it up!

	After more than 10 years it seems to run fine. The
old miniscribe ST-506 40 M drive seems fine. All the
floppies I tried to read seem fine.

	The HCA (Host Computer Adapter), the thing that
plugs into the slot is fairly simple. It contains a 65C52
serial chip, a 65xx (PIA) for parallel and ?, a RTC (DS1287),
and an "auto boot ROM".

	In the box containing the hard drive is the interface
card, a WD1002-05G. It has 4 40 pin WD chips:  WD1614AL-00,
WD1010AL-00, WD2797PL-02 (floppy chip), and a WD1015PL-00.
It can control three ST-506 hard drives and three floppies.

	The WDDisk driver manual mentions high capacity floppy
operation:  both 250/500 kbit bit rates and 300/360 rpm speeds
are mentioned. The little satellite board does more than control
motor speeds. It has only two chips:  a 74ls157 and a 7438.
Will this also work with 3.5" HD floppies?

	I did a dcheck on the hard drive and all the floppies.
I got no read or I/O errors. How good an indication is this
of the state of my media?

	80 columns on a composite TV is hard to read.

					kevin

P.S.:	Anybody play sub battle simulator. I spent hours
	playing this thing back then. Its a bloody good
	thing I was'nt a sub commander in WWII!

Willard Goosey wrote:
>>Date: Sat, 21 Aug 2004 08:55:55 -0700
>>From: Kevin Diggs <kevdig at hypersurf.com>
>>I believe the FHL eliminator that I have can also handle high
>>density drives. The manuals mention some simple circuit that
>>you have to build (I think it has something to do with motor
>>speeds).
> 
> 
> I've heard of the eliminator, but I don't know what it uses for a
> floppy controller.  My foggy memory says something about a WD1002, but
> that sounds like a hard-drive controller chip, to me.  
> 
> I'd be interested in more crunchy technical info about the
> eliminator.  
> 
> Willard