[Coco] Floppy drive/OS9 issue

[Gene Heskett]

On Saturday 22 July 2006 15:12, Andrew wrote:
>All,
>
>As some of you may or may not know, I am involved in a project to help
>convert some 400+ disks over to emulator formats. Normally this
> wouldn't be a problem, but in these early stages I have found
> something out that I didn't know before, and I am wondering if there
> is a solution of some sort.
>
>I am at a point in the project where I am verifying/checking-out a
> bunch of OS-9 floppies. My main problem is that some of these disks
> are two sided, and OS-9 L2 is complaining when I stick them in my
> drive, with an error #249 "Wrong Type", which according to the manual
> may mean they are double sided (one of the floppies was marked as
> double sided, so I am assuming for now this is the problem). Other
> OS-9 floppies read OK.
>
>Let me give you a little background on my drive situation, though.
> When I first had my Color Computer 2, I had a tape drive (this was
> about 1984 or so, and I was about 11 years old). About a year later I
> was given a floppy drive by my parents. It was an FD501 system, with
> the single half-height drive in a dual drive cabinet. A few years
> later I upgraded to a Color Computer 3, and a little after that got a
> 512K expansion (third party, but I can't remember who, just not the
> RS one).
>
>In high-school my drive controller died (still don't know why, and I
>still have it). I managed to get from a friend an FD502 controller
>cartridge. My drive worked at that point.
>
>About 10 years later I get all of my Color Computer stuff back from my
>parents house. I plan to do a conversion of my software to work on
>emulation. I try my drive, and it won't read anything. I purchase a
>drive off of a guy on ebay to replace the one I had. It works great,
> and I finish my conversion project.
>
>I was never an OS-9 fanatic, but I now want to get to know it better,
>since I didn't when I was younger, and I kinda need to for this floppy
>conversion project.
>
>So, here I am trying to go thru these floppies last night, and I am
>running into two issues - sometimes I need a command module which
> isn't loaded, so with a single sided system I am needing to swap
> floppies, and the other issue is that I have floppies that are double
> sided. I figure "hey, bright idea - I have another 5.25 drive in my
> shop (don't we all?), maybe it is double sided?" - thinking I will
> add the drive, and all will be well.
>
>I pull the drive out, and it is double sided - but it won't hook up to
>my system! Basically, it will plug in, but I can't use both drives
>because of the way the connector is configured and the cable
> connectors in the case - the one drive in the case has the connector
> on one side facing in one direction, and this other drive (by a
> different manufacturer) has it on the other side oriented differently
> - and the cable that goes in has the connectors space about an inch
> apart, can't twist them much, etc. Drats!
>
>Well - I figure I will just plug the new one in, and it will at least
>give me a double-sided drive, fixing one of my issues, hopefully. I
> try it out, and it doesn't quite work right - If I issue a DIR 0 (or
> just DIR) no action. But issuing a DIR 1 works OK. I take another
> look at the drive, and sure enough, there are a set of jumpers marked
> D0, D1, D2, and D3 - and the jumper is on D1 (interestingly, there is
> another set of jumpers labeled U0, U1, and U2 - the drive is a TEAC
> FD-55BR). I assume (though I have yet to try it), that if I pop it
> over to D0, it might work OK (?). But what about my other drive (the
> one I have been using for the past few years)? Does it have jumpers?
>
>I look at the drive closely, and I don't see any, but it has a cover
>obscuring the drive electronics. The cover looks like it is meant to
> be removeable, so I remove it carefully. What I see shocks me a
> little bit:
>
>...An upper drive head!
>
>All this time - the drive has been a double sided drive! But it
> doesn't seem to work as a double-sided drive! It only sees a single
> side. I also don't see any obvious jumpers. It is a CHINON FZ-502.
>
>So - after all this, my question to all of you guys is: what do I do?
>I have the folowing drives:
>
> CHINON FZ-502 (acts as a single sided drive, but is double)
>         TEAC FD-55BR (works as a single sided drive, but may jumper
> to double)
>
>Personally, I would like to have them both working, and have two
> double sided drives in my system (at some point in the future, when
> cloud-9 gets going again, I plan on getting a hard drive controller).
> It would make my OS-9 world much easier to work in, and would make
> this conversion much easier.
>
>Does anyone have any ideas on this - does anyone have any information
> on either of these drives or how I can/should set them up? Also, can
> I still buy the connectors that are on my cable to crimp my own
> custom cable so I can hook these drive up - what kind of connector is
> it (can I order it from DIGIKEY or someplace)?
>
>Any information posted will be appreciated! Thank you,
>
>-- Andrew L. Ayers
>    Glendale (Phoenix), Arizona

What you want is to pitch the missing teeth drive connectors in the 
trash, and replace them with connectors that have all the connections 
present.  One could at one time, purchase those connectors at the shack 
but they've been stripping the parts cabinet pretty badly of late so 
you may have to shop around or hit the catalogs.  You'll best use a 
small vise to install them properly, although I have used a hammer and 
or vise-grips.  The vise doesn't leave as many marks on the 
cosmetics. :)  You can re-space the connectors to make room for the 
twist required while you're working on the cable.

Once thats done, then put both drives in, one set as DS0 and one set as 
DS1.  Make sure the terminating resistors are only present in the drive 
thats last on the cable.  They'll probably be in a dip socket near the 
DSx jumpers.

Having established that, then the rest of it will be more or less self 
explanatory by looking up the docs on the dmode command.  And there are 
2 versions of that extant that I know about, with slightly different 
syntax requirements, but I don't have the edition numbers of the two of 
them commited to non-volatile wet ram.

There are also a lot of 80 track drives about, some rated at 720k, some 
at 1.2megs capacity.  Only the 720k can be used on the coco's without 
extensive mods to the controller, and it has to be the original, needs 
12 volts to run tandy version.  The 1.2 meg drives can be used at 720k 
IF you can find the motor speed jumper and slow it down from 360 rpm to 
300 rpm.

With the right floppy driver and the right descriptor settings via the 
dmode command, 40 track disks can be read, but not written to, in the 
80 track drives.  Writing to such a disk only writes a narrow piece of 
the 40 trackers wider track, and generally trashes the disk until its 
reformatted in the proper drive.

-- 
Cheers, Gene
People having trouble with vz bouncing email to me should add the word
'online' between the 'verizon', and the dot which bypasses vz's
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Copyright 2006 by Maurice Eugene Heskett, all rights reserved.