2 Apr
2016
2 Apr
'16
1:27 p.m.
I have been looking at my DECmate II recently. I got an Italian version of
WPS 1.0 for it and that works fine, except that I don't have an Italian
keyboard so finding some of the characters is a bit tricky. :)
The machine came with an RD51 hard disk. I can't many references to MFM
disks in DECmate IIs. The disk will sometimes spin up and sometimes remains
motionless. I checked all three of the Darlington transistors on the drive
board and they seemed fine (I checked them out of circuit). However, unless
I have any really persistent problems getting the disk to run, I am not
going to bother trying to make it start reliably.
My main question though is this. From what I can see the WPS software does
not access the hard disk, the manual I have does not mention hard disks. I
executed the function for listing files and it said it found nothing,
whether that attempted to access the hard disk or not I don't know. Should
WPS be able to access the hard disk? Might it have been a later version that
used the hard disk? If not, then would one of the other OSs for the DECmate
II be able to access the hard disk? I don't have any other OSs for it
though, does anyone know where I might find copies?
I also have a graphics option board for the machine, which software actually
uses this option?
Any recommendations for how best to image RX50 diskettes? I want to preserve
the diskettes I have.
Regards
Rob
2 Apr
2 Apr
1:49 p.m.
On Apr 2, 2016, at 1:27 PM, Robert Jarratt
<robert.jarratt at ntlworld.com> wrote:
I have been looking at my DECmate II recently. I got an Italian version of
WPS 1.0 for it and that works fine, except that I don't have an Italian
keyboard so finding some of the characters is a bit tricky. :)
...
Any recommendations for how best to image RX50 diskettes? I want to preserve
the diskettes I have.
Are they the same format (80 tracks, 10 sectors, 512 bytes) as the RX50 on PDP11s? If
yes, you can either use a PDP11, or you can configure Linux to 10 sector per track format
and use dd. If the sector ordering is as strange as on the PDP11, dd will get the data
very much out of order, but it should all be there. I can find the PDP11 interleave rules
if you need them.
paul
2:49 p.m.
-----Original Message-----
From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Paul
Koning
Sent: 02 April 2016 18:49
To: General Discussion: On-Topic and Off-Topic Posts
<cctalk at classiccmp.org>
Subject: Re: DECmate II Questions
10
On Apr 2, 2016, at 1:27 PM, Robert Jarratt
<robert.jarratt at ntlworld.com>
wrote:
I have been looking at my DECmate II recently. I got an Italian
version of WPS 1.0 for it and that works fine, except that I don't
have an Italian keyboard so finding some of the characters is a bit
tricky. :) ...
Any recommendations for how best to image RX50 diskettes? I want to
preserve the diskettes I have.
Are they the same format (80 tracks, 10 sectors, 512 bytes) as the RX50 on
PDP11s? If yes, you can either use a PDP11, or you can configure Linux to sector per track format and use dd. If the sector
ordering is as strange
as on
the PDP11, dd will get the data very much out of
order, but it should all
be
there. I can find the PDP11 interleave rules if you
need them.
I do have an 11/73 I might be able to press into service, although my first
thought was a MicroVAX II with VMS and using backup/image. Not sure if that
would work though? Ideally an image that I can then write back to "new"
diskettes, or possibly use in SIMH (if it ever gets DECmate emulation of
course).
Regards
Rob
3:03 p.m.
-----Original Message-----
From: Robert Jarratt [mailto:robert.jarratt at ntlworld.com]
Sent: 02 April 2016 19:50
To: 'General Discussion: On-Topic and Off-Topic Posts'
<cctalk at classiccmp.org>
Subject: RE: DECmate II Questions
> -----Original Message-----
> From: cctalk [mailto:cctalk-bounces at classiccmp.org] On Behalf Of Paul
> Koning
> Sent: 02 April 2016 18:49
> To: General Discussion: On-Topic and Off-Topic Posts
> <cctalk at classiccmp.org>
> Subject: Re: DECmate II Questions
>
>
> > On Apr 2, 2016, at 1:27 PM, Robert Jarratt
> > <robert.jarratt at ntlworld.com>
> wrote:
> >
> > I have been looking at my DECmate II recently. I got an Italian
> > version of WPS 1.0 for it and that works fine, except that I don't
> > have an Italian keyboard so finding some of the characters is a bit
> > tricky. :) ...
> > Any recommendations for how best to image RX50 diskettes? I want to
> > preserve the diskettes I have.
>
> Are they the same format (80 tracks, 10 sectors, 512 bytes) as the
> RX50 on PDP11s? If yes, you can either use a PDP11, or you can
> configure Linux to 10 sector per track format and use dd. If the
> sector ordering is as strange as on the PDP11, dd will get the data
> very much out of order, but it should all be there. I can find the
PDP11
interleave rules if you need them.
I do have an 11/73 I might be able to press into service, although my
first
thought was a MicroVAX II with VMS and using
backup/image. Not sure if
that would work though? Ideally an image that I can then write back to
"new"
diskettes, or possibly use in SIMH (if it ever gets
DECmate emulation of
course).
Sorry Paul, I just realised I didn't answer your question. Unfortunately I
don't know, and the docs I got from Manx/BitSavers don't cover the RX50.
Regards
Rob
3 Apr
3 Apr
1:35 p.m.
On Sat, Apr 2, 2016 at 11:49 AM, Paul Koning <paulkoning at comcast.net> wrote:
They are similar to the PDP-11 layout, with special rules for tracks 0, 1
and 79 IIRC. So long as
you are using a compatible floppy drive, you'll be able to read / write
them. I've connected my
RX-50 from my DEC Rainbow 100B to a PC controller in the past with some
luck in reading
writing the disks (raw mode only). I've also had good luck with the TEAC
55F. Other models, like
ones in IBM PC AT and newer that do 1.2 MB have 'issues' creating readable
RX-50 disks.
DD certainly would be one way to image them. However, there's a caveat with
that. DD
will read the sectors labeled 1, 2, 3, ... 10 in that order. However, if
you read the entire track
off the disk you'll find they are stored in 1 6 2 7 3 8 4 9 5 10 order
(again, IIRC, the order is
different, but might not be this exactly). Back in the day, people (not me)
reported success of
duplicating via dd, only to find that the performance really sucked. My
brain can't recall if
this was on the PDP-11 / Professional formatted disks, or on the DECmate II
disks.
Wish I could be more helpful. Here's a link that has all the details that
my brain is likely
recalling wrong:
http://www.ibiblio.org/pub/academic/computer-science/history/pdp-8/docs/rx5…
Warner
On Apr 2, 2016, at 1:27 PM, Robert Jarratt
<robert.jarratt at ntlworld.com>
wrote:
I have been looking at my DECmate II recently. I got an Italian version
of
WPS 1.0 for it and that works fine, except that I
don't have an Italian
keyboard so finding some of the characters is a bit tricky. :)
...
Any recommendations for how best to image RX50 diskettes? I want to
preserve
the diskettes I have.
Are they the same format (80 tracks, 10 sectors, 512 bytes) as the RX50 on
PDP11s? If yes, you can either use a PDP11, or you can configure Linux to
10 sector per track format and use dd. If the sector ordering is as
strange as on the PDP11, dd will get the data very much out of order, but
it should all be there. I can find the PDP11 interleave rules if you need
them.
2:43 p.m.
On Apr 3, 2016, at 1:35 PM, Warner Losh <imp at
bsdimp.com> wrote:
...
DD certainly would be one way to image them. However, there's a caveat with
that. DD
will read the sectors labeled 1, 2, 3, ... 10 in that order. However, if
you read the entire track
off the disk you'll find they are stored in 1 6 2 7 3 8 4 9 5 10 order
(again, IIRC, the order is
different, but might not be this exactly). Back in the day, people (not me)
reported success of
duplicating via dd, only to find that the performance really sucked. My
brain can't recall if
this was on the PDP-11 / Professional formatted disks, or on the DECmate II
disks.
I was assuming that you'd use dd both to save and to restore the disks, or to create
disk images to be read by something that expects sectors in physical order. That way, it
doesn't matter what the interleave rule is.
On the PDP11, there is both 2:1 interleaving and track skew. Also, for some bizarre
reason, logical track 0 is physical track 1, while physical track 0 holds logical track
79.
The equations are:
phys track = ((lba + 10) / 10) mod 80
phys sec = ((sec mod 5) * 2 + ((sec / 5) mod 2) + (sec / 10) * 3
if I translated from the original Macro-11 correctly.... :-)
On the Pro, the driver handles that translation; on other PDP11s where the RX50 is
connected to an MSCP controller, the controller does the job, but the address mapping is
the same in both cases.
paul
3037
days inactive
3038
days old
5 comments
3 participants
participants (3)
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imp＠bsdimp.com -
paulkoning＠comcast.net -
robert.jarratt＠ntlworld.com