[Coco] Regarding a cheap floppy emulator

[Christopher Smith]

Yes, I'm getting the idea that the cheaper emulators just don't do soft sectoring correctly at all. :)  It was a nice thought anyway.  The Lotharek emulator seems to be the way to go -- as I'd suspected before -- but of course it's 3x as much or more in cost, which is a bit high for me at the moment.  I suppose a real floppy drive will be the way to go for now.  That leaves me a few different options:

First, I guess I could slot an identical drive in, QD 5.25" all around, with maybe switches on them to select whether they actually operate as QD.  Next, I could probably throw in a 3.5" drive.  I don't have a 720k one for now, but I do have a 1.4M one that I'm not completely opposed to forcing into 720k mode permanently by obstructing the medium sense switch.  That might work, and this drive does have drive selection jumpers.  This could give me a set of two drives of identical capacity but with different disk types.  I guess I could also rig something up to swap drive 0 from one to the other, and I could leave the density selector switch on the 5.25" drive in order to read old disks. ... or I could slot in a real 360k drive.  Both drives would be 5.25" disks, but at different densities.  If I can pull something off to select which is drive 0 and which is drive 1, this will make a density selection switch for the QD drive unnecessary.  There's a certain elegance to that solution.

Am I missing any possibilities?  Anyone want to comment on the relative merits of the above options?

Chris

----- Original Message -----
> From: "Juan Castro" <jccyc1965 at gmail.com>
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Sent: Monday, September 9, 2013 3:24:09 PM
> Subject: Re: [Coco] Regarding a cheap floppy emulator
> 
> I tested the 720K one in a Dragon with a Lafumat controller. It
> kinda,
> sorta works, but you can only read and write the first 256 bytes of
> each sector of side 0 -- and there's only 9 of them in each track, so
> no go. So close and yet so far.
> 
> With the 1.44 emulator (which I expected would work in similar
> fashion, and it has 18 sectors per track) the Dragon can't even read
> anything.
> 
> After that, I decided it was futile to test on a CoCo. Bummer.
> 
> Juan
> 
> On Mon, Sep 9, 2013 at 3:17 PM, Robert Hermanek
> <rhermanek at centurytel.net> wrote:
> > I played around with a China (affordable) emulator and verified, as
> > expected, that although they work fine in a PC with 720 or 1440
> > images, they
> > do not work in the coco.  The cheaper emulators are not
> > configurable in any
> > way, and always expect 80 tracks, 9 or 18 sectors per track, 512
> > byte
> > sectors.  I was hoping against hope that with coco being 35 tracks,
> > 18
> > sectors, that the emulator would live with it, but I think the 256
> > vs 512
> > byte sectors was a deal breaker.
> >
> > -RobertH
> >
> >
> > On 9/9/2013 1:09 PM, Christopher Smith wrote:
> >>
> >> So, given that I may need to build my CoCo disk system from parts
> >> anyway,
> >> I've been looking at the possibility of emulating one out of two
> >> floppy
> >> drives in hardware.  There is at least one very impressive floppy
> >> emulator
> >> available which will do everything I want, but it's upward of $100
> >> and the
> >> budget isn't so great for now.  I'm looking at the possibility
> >> using a
> >> Chinese import emulator from ebay.  Supposedly it will emulate a
> >> 720k, 1.2M,
> >> and 1.44M floppies.  Now, of these formats, I'm reasonably sure
> >> the CoCo
> >> won't like any but the first.  That may be sufficient.  Here's
> >> what I'm
> >> considering:
> >>
> >> I have a Teac 5.25" drive on order.  It's high-density, but people
> >> say
> >> that these things have an RPM jumper on them which will slow the
> >> spindle
> >> down.  You can then either force them to double-density mode or
> >> have them
> >> function as quad-density.  People also say that the quad-density
> >> disks will
> >> work out ok under OS-9.  I'd like to fit a switch onto the density
> >> selector
> >> so that I can force the drive into either double or quad density
> >> mode at any
> >> given time.  So that should make one good drive.
> >>
> >> I'm also thinking about trying one of those floppy emulators.  It
> >> would
> >> need to be forced into 720k mode, and would basically work
> >> similarly to the
> >> 5.25" disk in quad-density mode, I suspect.  The downside is that
> >> the
> >> emulated disks would be smaller than usual under DECB, and unless
> >> I flipped
> >> sides there either by attaching another switch that mucks around
> >> with the
> >> side select signal on the cable or in software, I lose half of the
> >> space in
> >> a disk image that I might have still had.  Though, OS-9 should use
> >> them at
> >> full capacity, one would think.  My other problem here is that I
> >> strongly
> >> suspect that this emulator will not have drive select jumpers, so
> >> I may need
> >> to end up clipping pins, or -- who knows what, really -- to get
> >> the drives
> >> in the order I'd like.  Really I think the emulated floppy should
> >> be drive 0
> >> and the actual floppy 1.
> >>
> >> Any comments or suggestions on how to do this or why it's a bad
> >> idea and
> >> something else should be done instead? :)
> >>
> >> All that aside, I'll still have the problem of housing the drives.
> >>  I've
> >> recently salvaged an old case that had a CD-ROM in it, which
> >> should be
> >> sufficient for a single drive, but I don't really have anything
> >> appropriate
> >> for two drives.  A standard (and as small as possible) PC power
> >> supply of
> >> even 60W or so should do fine for power, I think.  As for the box,
> >> I'm not
> >> quite sure what to do there.  Perhaps wood I could do on my own.
> >>  Maybe I
> >> could have something fabricated out of metal.  Something else?
> >>  Any ideas
> >> here will be welcome as well.
> >>
> >>
> >> Chris
> >>
> >
> >
> > --
> > Coco mailing list
> > Coco at maltedmedia.com
> > http://five.pairlist.net/mailman/listinfo/coco
> 
> --
> Coco mailing list
> Coco at maltedmedia.com
> http://five.pairlist.net/mailman/listinfo/coco
> 

-- 
Christopher Smith
Systems Engineer, Wolfram Research