12 Mar
2022
12 Mar
'22
3:20 p.m.
I have some disks that look like they're from a DECmate II computer,
standard RX50K drives. The disk images all look like they're a mix of
12-bit (OS/78 or OS/278?) and 8-bit all on the same media. I can't
convince PUTR to make sense of the images, so I'm wondering if there is
anything else out there that is likely to be able to examine the disk
contents? I'm really looking for PUTR-like functionality to list and copy
files.
Maybe SIMH could be configured to be a DECmate II and be fed the disks?
I have a couple of disk images available in case anyone wants to try them
out - they're purported to be "DECmate II CP/M 2.2 version 2.0" and
"System
Disk ver. 2.0 8/24/87":
https://drive.google.com/drive/folders/1PD0TlUPiT7MIPEX6abEn33e7s3kSXp_H?us…
- David
12 Mar
12 Mar
5:55 p.m.
I'm not sure what would be on the "System Disks? but it's probably OS/78 or
278. As far as the CP/M disks and the 8-bit component of the disks, those are for the Z-80
expansion card which Simh does not emulate.
Ray
Get Outlook for Android<https://aka.ms/AAb9ysg>
________________________________
From: cctech <cctech-bounces at classiccmp.org> on behalf of David Schmidt via
cctech <cctech at classiccmp.org>
Sent: Saturday, March 12, 2022 3:20:15 PM
To: General Discussion: On-Topic Posts <cctech at classiccmp.org>
Subject: DECmate II disk image tooling?
I have some disks that look like they're from a DECmate II computer,
standard RX50K drives. The disk images all look like they're a mix of
12-bit (OS/78 or OS/278?) and 8-bit all on the same media. I can't
convince PUTR to make sense of the images, so I'm wondering if there is
anything else out there that is likely to be able to examine the disk
contents? I'm really looking for PUTR-like functionality to list and copy
files.
Maybe SIMH could be configured to be a DECmate II and be fed the disks?
I have a couple of disk images available in case anyone wants to try them
out - they're purported to be "DECmate II CP/M 2.2 version 2.0" and
"System
Disk ver. 2.0 8/24/87":
https://drive.google.com/drive/folders/1PD0TlUPiT7MIPEX6abEn33e7s3kSXp_H?us…
- David
13 Mar
13 Mar
10:57 a.m.
Good point about the CP/M disk - actually it is read just fine with
cpmtools with this diskdef:
# PRO CP/M RX50 DZ format (Perhaps only 79 tracks should be used?)
diskdef dec_pro
seclen 512
tracks 80
sectrk 10
blocksize 2048
maxdir 128
skew 2
boottrk 2
os 2.2
end
So I'm left with figuring out how to pull files off of 12-bit OS/{2}78
disks.
- David
On Sat, Mar 12, 2022 at 5:55 PM Ray Jewhurst <raywjewhurst at gmail.com> wrote:
I'm not sure what would be on the "System
Disks? but it's probably OS/78
or 278. As far as the CP/M disks and the 8-bit component of the disks,
those are for the Z-80 expansion card which Simh does not emulate.
Ray
Get Outlook for Android <https://aka.ms/AAb9ysg>
------------------------------
*From:* cctech <cctech-bounces at classiccmp.org> on behalf of David Schmidt
via cctech <cctech at classiccmp.org>
*Sent:* Saturday, March 12, 2022 3:20:15 PM
*To:* General Discussion: On-Topic Posts <cctech at classiccmp.org>
*Subject:* DECmate II disk image tooling?
I have some disks that look like they're from a DECmate II computer,
standard RX50K drives. The disk images all look like they're a mix of
12-bit (OS/78 or OS/278?) and 8-bit all on the same media. I can't
convince PUTR to make sense of the images, so I'm wondering if there is
anything else out there that is likely to be able to examine the disk
contents? I'm really looking for PUTR-like functionality to list and copy
files.
Maybe SIMH could be configured to be a DECmate II and be fed the disks?
I have a couple of disk images available in case anyone wants to try them
out - they're purported to be "DECmate II CP/M 2.2 version 2.0" and
"System
Disk ver. 2.0 8/24/87":
https://drive.google.com/drive/folders/1PD0TlUPiT7MIPEX6abEn33e7s3kSXp_H?us…
- David
11:32 a.m.
On 3/13/2022 7:57 AM, David Schmidt via cctech wrote:
Good point about the CP/M disk - actually it is read
just fine with
cpmtools with this diskdef:
# PRO CP/M RX50 DZ format (Perhaps only 79 tracks should be used?)
diskdef dec_pro
seclen 512
tracks 80
sectrk 10
blocksize 2048
maxdir 128
skew 2
boottrk 2
os 2.2
end
So I'm left with figuring out how to pull files off of 12-bit OS/{2}78
disks.
If you can extract the byte stream from the IMD/IMG files (and
de-interleave them if necessary into logical order), I have tools to
read the OS/8, COS, etc. file-systems.
The tools want essentially a 16 bit short for each 12 bit word, in
logical order. I think this is essentially what you get for the
"inefficient" 12 bit mode. I also have tools to unpack some of the
interlaced 8-bit formats for RX01/RX02, and those tools may be adaptable
to the RX50.
Vince
12 Mar
12 Mar
8:11 p.m.
On 3/12/2022 3:20 PM, David Schmidt via cctech wrote:
I have some disks that look like they're from a
DECmate II computer,
standard RX50K drives. The disk images all look like they're a mix of
12-bit (OS/78 or OS/278?) and 8-bit all on the same media. I can't
convince PUTR to make sense of the images, so I'm wondering if there is
anything else out there that is likely to be able to examine the disk
contents? I'm really looking for PUTR-like functionality to list and copy
files.
Since it's a DECMate II, these may be WPS disks.
At least for the RX01/RX02, Those are 8-bit mode except for the boot
sector (because the standard boot was for a 12-bit mode disk.)? I don't
know the layout for the RX50 - since it's not using the RX boot, there
shouldn't have been a need for a 12-bit boot sector.
It's also possible they're COS-310 disks, which also were 8-bit mode.?
Using byte mode allowed WPS and COS to use the full capacity of the
disks.? Apparently the RX50 controller retained this wasteful 12-bit mode.
Maybe SIMH could be configured to be a DECmate II and
be fed the disks?
SIMH doesn't have an emulation for the RX50 controller on the DM2.?
There's probably a different interleave being used here, so decoding the
layout would be a matter of trial-and-error.
The specs for the RX50 controller are available -
http://www.bitsavers.org/pdf/dec/pdp8/cmos8/DECmate/Decmate_II_Specificatio…
That means that an emulator is possible.
??? -Rick
9:08 p.m.
David,
I have a working DECmate III I could try your images on.
Tom
On Sun, 13 Mar 2022, 4:20 am David Schmidt via cctech, <
cctech at classiccmp.org> wrote:
I have some disks that look like they're from a
DECmate II computer,
standard RX50K drives. The disk images all look like they're a mix of
12-bit (OS/78 or OS/278?) and 8-bit all on the same media. I can't
convince PUTR to make sense of the images, so I'm wondering if there is
anything else out there that is likely to be able to examine the disk
contents? I'm really looking for PUTR-like functionality to list and copy
files.
Maybe SIMH could be configured to be a DECmate II and be fed the disks?
I have a couple of disk images available in case anyone wants to try them
out - they're purported to be "DECmate II CP/M 2.2 version 2.0" and
"System
Disk ver. 2.0 8/24/87":
https://drive.google.com/drive/folders/1PD0TlUPiT7MIPEX6abEn33e7s3kSXp_H?us…
- David
862
days inactive
863
days old
5 comments
5 participants
participants (5)
-
ccth6600＠gmail.com -
david4602＠gmail.com -
raywjewhurst＠gmail.com -
rick＠rickmurphy.net -
vincent.slyngstad＠gmail.com