Kaypro 4/84 questions - test-drb@ccmp.vtda.org

7 Nov 2007

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Subject: Re: Kaypro 4/84 questions
   From: Brian Wheeler <bdwheele at indiana.edu>
   Date: Wed, 07 Nov 2007 11:26:54 -0500
     To: "General Discussion: On-Topic and Off-Topic Posts" <cctalk at
classiccmp.org>

On Mon, 2007-11-05 at 17:54 -0400, Roy J. Tellason wrote:
  On Monday 05 November 2007 13:13, Brian Wheeler
wrote:
  * I'd like to replace the 2nd drive with a
3.5" floppy.  I've found a
 Sony HD drive along with a power and plug converter.  Knowing that PCs
 use a twisted cable scheme, what things should I be aware of when
 cabling in this new drive?  
 The twist in the cable was to not have to worry about jumper settings which 
 you had to deal with prior to that point.  Those drive select jumpers are 
 marked,  depending on the brand,  either 0-3 or 1-4 on the drive electronics, 
 with the first two choices being the ones commonly used (0 and 1,  or 1 and 
 2).  The cable with the twist setup has both drives set to the second choice,  
 so you probably won't need to worry about messing with anything there,  
 selecting the drive should be apparent as Kaypros tend to leave the light on 
 all the time.

  Will it be supported in some manner by the
software?  
 Hm,  kinda doubtful,  though I couldn't say for sure as it's been a long time 
 since I dove into those particular interface specs.

  Its not a big deal if it turns out to be a 360K
3.5" floppy,  as long as its
 readable by my linux box.   
 That might just be what you end up with.  Do tell us when you find out,  I'd 
 be curious to know...

I've got the 3.5" drive installed and cabled and it seems to be working
rather well.  I ended up using vice grips to get the screws loose in the
drive cage since the heads kept wanting to strip.  As I suspected, it
really thinks its just a DSDD 5.25" drive.  I formatted a disk using
mfdisk as an IBM 9 sector DS disk and could read it (as 360K) without
problems on my linux box.  

The drive I ended up using was a chinon FZ-357 which has a jumper for
RDY as well as drive select jumpers.  It also had the interface pins on
the same side as the original disk so I could use the original cable.
All of my other 3.5" drives had it on the other side, but the cable
wasn't long enough to shift sideways enough.

Its weird when it does a format since it counts tracks from 0 to 79 but
its really counting cylinder 1 as tracks 0 and 1, etc.

However, trying to read a kaypro formatted disk isn't working.  It reads
4K and then fails.  Anybody used setfdprm on linux to set up reading
kaypro iv/10 disks?   They look like they're 10 sector (numbered 0x0a -
0x13), rate=2 disks.   
You may have to notify the software of what format is being used.

...
 I'll probably mount the 5.25" DSDD drive in my
linux box as well, but
it'd be nice to know how to read disks without hassle :)

Now for some more questions:

* is it possible to run CP/M 3.x on it, or am I limited to 2.2G? 
Yes, but without any banked memory.

...
 * what's the J9 header for?  It looks like it has 8
data bits and 8
address bits wired to it (at least according to the schematics I've
found).  Seems like it'd be possible to hang a home-made IDE interface
onto it (if I ever get time/inclination) 
Its host interface  for WD1001HDO HDC, Sorta like IDE save for the 
board was bigger than the drive, it wasn't integrated, it was 8bit
and the registers were slightly differnt.   To do IDE with that 
should be easy as its basiccally the process or bus for IO. There 
will not be software support (BIOS) unless you do it. 

Allison

...

Thanks to all of the suggestions and advice!

Brian