16 Apr
2025
16 Apr
'25
6:53 p.m.
Hello all,
I have transferred some simh .tap files to my PDP-11/23+ running RSX11M+.
There I have tried to use VCP to attach them to a virtual device but I keep
getting an invalid record format error. I then realized the simh .tap files
most likely aren't organized correctly. If I attach them to TS0 in simh I
can work with them. So now I am trying duplicate a tape into a new .tap
file created using VCP. I can't for the life of me get it to work though.
BRU doesn't support tape-to-tape and FLX doesn't complain but also never
completes. Is there a process for tape duplication under RSX?
The images were first transferred to my PiDP-11 using ftp in binary mode
over TCP/IP. From there I used NFT in image mode and I tried both record
and block modes.
I have also seen the simh tape tools but there doesn't seem to be a tool to
convert a simh file back to what would be on a real tape.
Anyone have any information or pointers to get this to work?
Thanks!
-Peter
16 Apr
16 Apr
7:12 p.m.
On 4/16/25 11:53, Peter Ekstrom via cctalk wrote:
Hello all,
I have transferred some simh .tap files to my PDP-11/23+ running RSX11M+.
There I have tried to use VCP to attach them to a virtual device but I keep
getting an invalid record format error. I then realized the simh .tap files
most likely aren't organized correctly. If I attach them to TS0 in simh I
can work with them. So now I am trying duplicate a tape into a new .tap
file created using VCP. I can't for the life of me get it to work though.
BRU doesn't support tape-to-tape and FLX doesn't complain but also never
completes. Is there a process for tape duplication under RSX?
I wrote some stand-alone programs that did mag tape copies,
and directory listings in Fortran on RSX-11M and VMS.
I could send you these if you have Fortran on your system.
Jon
7:40 p.m.
On Wed, Apr 16, 2025 at 1:21 PM Jon Elson via cctalk <cctalk(a)classiccmp.org>
wrote:
On 4/16/25 11:53, Peter Ekstrom via cctalk wrote:
That is part of my dilemma, I am trying to install Fortran among others.
But being a physical machine, the SIMH images aren't working.
I'd still be interested in the programs though if you don't mind sharing.
-Peter
Hello all,
I have transferred some simh .tap files to my PDP-11/23+ running RSX11M+.
There I have tried to use VCP to attach them to a virtual device but I
keep
getting an invalid record format error. I then
realized the simh .tap
files
most likely aren't organized correctly. If I
attach them to TS0 in simh I
can work with them. So now I am trying duplicate a tape into a new .tap
file created using VCP. I can't for the life of me get it to work though.
BRU doesn't support tape-to-tape and FLX doesn't complain but also never
completes. Is there a process for tape duplication under RSX?
I wrote some stand-alone programs that did mag tape copies,
and directory listings in Fortran on RSX-11M and VMS.
I could send you these if you have Fortran on your system.
Jon
Hi Jon,
10:46 p.m.
On 4/16/25 12:40, Peter Ekstrom via cctalk wrote:
On Wed, Apr 16, 2025 at 1:21 PM Jon Elson via cctalk
<cctalk(a)classiccmp.org>
wrote:
Well, actually, I have an RSX-11M executable of the
program. I don't know if that would run on an RSX-11M+ OS,
but it seems like maybe it would. It might require
byte-hacking the tape drive unit addresses.
Let me know if you want to try this. I have placed a zip
file named magtape.zip on my server at:
http://pico-systems.com/codes/magtape.zip
Let me know if you have any problems with this.
Jon
Jon
On 4/16/25 11:53, Peter Ekstrom via cctalk
wrote:
That is part of my dilemma, I am trying to install Fortran among others.
But being a physical machine, the SIMH images aren't working.
I'd still be interested in the programs though if you don't mind sharing.
Hello all,
I have transferred some simh .tap files to my PDP-11/23+ running RSX11M+.
There I have tried to use VCP to attach them to a virtual device but I
keep
getting an invalid record format error. I then
realized the simh .tap
files
most likely aren't organized correctly. If I
attach them to TS0 in simh I
can work with them. So now I am trying duplicate a tape into a new .tap
file created using VCP. I can't for the life of me get it to work though.
BRU doesn't support tape-to-tape and FLX doesn't complain but also never
completes. Is there a process for tape duplication under RSX?
I wrote some
stand-alone programs that did mag tape copies,
and directory listings in Fortran on RSX-11M and VMS.
I could send you these if you have Fortran on your system.
Jon
Hi Jon,
22 Apr
22 Apr
7:31 p.m.
Hi Jon,
I have downloaded your zip-file and will take a look at it.
I have managed to create tape images using RSX11M+ running in simh and
using VCP to create a TS11 image.
The TS11 device was able to read the tape images I have for simh. So that
way I was able to look at the contents
of the tape, and then use BRU to restore everything. After that I wrote a
very basic CMD-file that put everything I
had restored onto a tape image connected via VCP in the same order as the
original.
After that, I NFTed the images I had created to my PDP-11/23+ in blocked
image mode. Once that was done, I
used VCP to connect the images and I could restore the auto-installer and
run @autoin to install both PDP-11 C
and Fortran 77. So now I have C and F77 on my PDP-11/23+!
I don't know if those VCP images are like actual raw images that could have
come off of a physical tape, but at
least I can access them using VCP on my hardware so I'm happy.
Next I am going to attempt to compile your tapedup utility and see how that
goes. I have never written or compiled
anything in Fortran77 before so it will be interesting.
-Peter
On Wed, Apr 16, 2025 at 4:56 PM Jon Elson via cctalk <cctalk(a)classiccmp.org>
wrote:
On 4/16/25 12:40, Peter Ekstrom via cctalk wrote:
That is part of my dilemma, I am trying to install Fortran among others.
But being a physical machine, the SIMH images aren't working.
I'd still be interested in the programs though if you don't mind sharing.
Well, actually, I have an RSX-11M executable of the
program. I don't know if that would run on an RSX-11M+ OS,
but it seems like maybe it would. It might require
byte-hacking the tape drive unit addresses.
Let me know if you want to try this. I have placed a zip
file named magtape.zip on my server at:
http://pico-systems.com/codes/magtape.zip
Let me know if you have any problems with this.
Jon
Jon
On Wed, Apr 16, 2025 at 1:21 PM Jon Elson via
cctalk <
cctalk(a)classiccmp.org>
wrote:
> On 4/16/25 11:53, Peter Ekstrom via cctalk wrote:
>> Hello all,
>>
>> I have transferred some simh .tap files to my PDP-11/23+ running
RSX11M+.
>> There I have tried to use VCP to attach
them to a virtual device but I
> keep
>> getting an invalid record format error. I then realized the simh .tap
> files
>> most likely aren't organized correctly. If I attach them to TS0 in
simh I
>> can work with them. So now I am trying
duplicate a tape into a new .tap
>> file created using VCP. I can't for the life of me get it to work
though.
>> BRU doesn't support tape-to-tape and
FLX doesn't complain but also
never
completes. Is there a process for tape duplication
under RSX?
I wrote some stand-alone programs that did mag tape copies,
and directory listings in Fortran on RSX-11M and VMS.
I could send you these if you have Fortran on your system.
Jon
Hi Jon,
23 Apr
23 Apr
12:10 a.m.
On 4/22/25 12:31, Peter Ekstrom via cctalk wrote:
Hi Jon,
Next I am going to attempt to compile your tapedup utility and see how that
goes. I have never written or compiled
anything in Fortran77 before so it will be interesting.
Unfortunately, I didn't see a compile and link command file
to link the tapedup program with mtape, and my memories of
RSX-11M have been overwritten with VMS stuff. Hopefully,
you can find some docs online for running the link step.
Jon
17 Apr
17 Apr
4:26 p.m.
On Wed, Apr 16, 2025 at 8:01 PM Peter Ekstrom via cctalk <
cctalk(a)classiccmp.org> wrote:
I have also seen the simh tape tools but there
doesn't seem to be a tool to
convert a simh file back to what would be on a real tape.
Anyone have any information or pointers to get this to work?
SIMH tape format inserts 4 bytes before and after each tape record. The 4
bytes
hold a 32-bit record length, and that length is placed both before and
after the
record to allow a tape to be read backwards. If the record is an odd
number of
bytes it is padded to be an even number by adding a zero byte. The length
should
indicate the 'true' (odd) record length in such cases. File marks on the
tape are
indicated with a single 4-byte marker of all zero bytes. The practice of
indicating end of tape with 2 consecutive file marks would be represented
by having 8 zero bytes.
Because a tape can contain arbitrary-sized records, there is no simple way
to convert a SIMH tape file to a 'real' tape image short of writing it to a
real
tape. That is, a 'tape image' would need to have some way to encode the
record lengths and presence of file marks.
But if you happen to know that your tape contains all the same-size records
or that the program reading the tape won't care what the record size is, and
you don't need to preserve file marks, you can strip out all those markers.
There are tools out there to 'enblock' and 'deblock' tape images, for
example
the TUHS archive has one but it's buried here:
https://www.tuhs.org/Archive/Distributions/Research/Bug_Fixes/V6enb/
That folder contains mostly stuff for working with Unix 6th Edition; you can
safely ignore everything besides the enblock/deblock utilities.
-ken
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Kenneth Gober -
Peter Ekstrom