[vcf-midatlantic] using catweasel to format an RX01

william degnan billdegnan at gmail.com
Thu Aug 10 10:15:45 EDT 2017

On Thu, Aug 10, 2017 at 7:29 AM, corey cohen via vcf-midatlantic <
vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:

> > On Aug 10, 2017, at 6:50 AM, Ian Primus via vcf-midatlantic <
> vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> >
> > Yes - it has to be single density. Just about any CP/M system with 8"
> > disks should be able to format single density ones. The IBM 3740
> > format was kind of the standard interchange format - a lowest common
> > denominator that most systems could handle. There is an XXDP utility
> > that can be used to update such disks to RX02 format - requires an
> > RX02, of course. I do not believe there is anything to go the other
> > way. The DEC RX02 format is special and weird. It uses the same base
> > single density formatting, using single density sector headers with
> > double density data areas. As such, really nothing else can create it.
> > My method for creating RX02 media has been to format blank disks as
> > single density on something else, then use the XXDP util to update
> > them to RX02.
> >
> > I'm sure you can format RX01 disks with a Catweasel, I just have no
> > idea how this is done. I don't have a Catweasel and have never seen
> > one. You can, however, use ImageDisk and a compatible PC controller to
> > format single density disks - which is a method I've used to get RX01
> > blanks as well.
> >
> > -Ian
> >
> > On Wed, Aug 9, 2017 at 11:59 PM, william degnan via vcf-midatlantic
> > <vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> >> As long as it's single density though. Right?  Not sure if I have a cp/m
> >> system w/ single density 8" drives.  I'll have to check.  Thanks for the
> >> tip.  Of anyone going to then workshop has any I will trade rx01 for
> rx02.
> >> i have a lot of tx02's
> >>
> >> On Aug 9, 2017 10:04 PM, "Ian Primus via vcf-midatlantic" <
> >> vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> >>>
> >>> If you have any CP/M machine that uses 8" disks, you can use that to
> >>> format blank RX01 media. It's just IBM 3740 SSSD - at least, in the
> >>> low level. Then you can do the high level formatting on the DEC
> >>> machine.
> >>>
> >>> -Ian
> >>>
> >>> On Wed, Aug 9, 2017 at 8:43 PM, william degnan via vcf-midatlantic
> >>> <vcf-midatlantic at lists.vintagecomputerfederation.org> wrote:
> >>>> Anyone ever formated an 8" disk to be used in an RX01 using a
> catweasel
> >>>> controller?  Curious if it's worth trying this route.  I have a Tandon
> >> 848
> >>>> drive.
> >>>> Bill
> Not sure I'm following here, but are you saying he just needs a cp/m
> formatted disk and can convert it to RX02 on the RX02?
> Is the RX01, hard or soft sectors?  If Hard then I can make a bunch of
> C/PM formatted 8" disks for him, I have CP/M for my Helios.

My question was essentially, "has anyone formatted an 8" disk to IBM 3740
format using a catweasel?  I don't think it's necessary though.

Assuming your Helios drive is a Percsi 277 yes it can produce IBM 3740
format disks, but you may have to specify this as part of the format
process.  IBM 3740 format may be called "FM" SSSD (?) or they may ask you
to specify 77 tracks 26 sector per 128 byte --> 256k bytes).

If it's easy for you to make these disks because you're already set up,
that'd save me the trouble of setting up a system here but it's not
necessary.  If you do let me know so I can bring you new SSSD disks in
exchange for the ones you make for me, please advise.  I have an XOR S-4
S-100 sysytemthat I can format the disks with, I believe it'll do IBM 3740
format, or worst case I can set up a Shugart 801 onto something.  I just
wanted to see if the catweasel could do it too because I already have that
set up, I was just getting started playing around with it.

NOTE:   I have RX02 disks if anyone wants a couple, I don't have an rx02
drive.  I can bring to the workshop.

I got a request to bring my Lear Siegler ADM3a terminal box to the workshop
(I offered to give it away) but it's too big for my car and passengers to
fit.  Joe O has first dibs, but it's first come first served but you have
to come here to get it.  If I don't get any takers soon I will use the box
for something else.


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