[Simh] DG Nova booting from another file or "device"?
Microtech Dart
microtechdart at gmail.com
Wed Nov 18 04:21:52 EST 2015
Bruce! This is very exciting...you actually RAN the file! I'm so excited
to know that this is possible.
I received the screen shots in my MightyFrame email, thank you for those.
Most of what you are talking about is still Greek to me, but I'll catch up.
"The tape file itself needs to be created in the SimH tape if it is to be
used with the default SimH tape driver. The QIC format may exist as a
single large data record of 16,384 bytes, or of multiple 512-byte records
followed by a file mark. (I can not tell its original format given only the
.bin file to work with.)"
OK, so I know exactly how the data format was written to this tape. (For
detail on the format itself, I outline it in exhaustive detail on this
page: http://bit.ly/1RhcdK2 ) The format is neither QIC-11 nor QIC-24,
but some very weird format that I've traced back to a specific model of
Kennedy QIC tape drive.
The Minicom Disk Utility file that you ran was in one single block of data,
which was 8192 bytes long. It was, as you indicate, the very first block
of data on the tape. This block was followed by a filemark.
The next block after the filemark was also 8192 bytes (with nearly, but not
exactly the same content as this Minicom utility file), but thereafter,
every other block on the tape was only 4096 bytes long, as was all of the
other blocks on the entire tape. (Notice that this is either 8 or 16 times
the length of a "normal" QIC-11 or QIC-24 512-byte data block).
This tape was marked "LU0, position 1; LU1, position 2; LU2, position 3",
so I expect this tape to have those 3 logical units on it.
It seems that there are 3 more filemarks on this tape (if I counted
correctly), so then this tape has 4 files, one file for the Minicom Disk
Utility, and one file for each of the Logical Units.
I can tell you right now that the LU0 file (if that is really what it is),
is 1,331,200 bytes, or exactly 1,300 Mb (if I did the math right). The
other 2 files I need to study more deeply to tell for sure, as they span
the tape tracks, and are more complicated for me to assemble.
Would it be best to just work with those as files, or do they need to be
kept in their original "Kennedy" block formation, or another block
formation or format?
Bruce, it is my goal to restore these tapes, and get a machine to run again
as close as possible to the way it would have when these backups were
made. With your ability to run the Minicom file, it gives me great hope
that this is possible.
What would be my next steps to get myself working on a system that has the
capability of doing this? I'm open to whether that is SimH, reNOVAte, or
other.
Thank you again, Bruce, this is very exciting news!
-AJ
On Wed, Nov 18, 2015 at 1:42 AM, Bruce Ray <Bruce at wild-hare.com> wrote:
> G'day AJ -
>
> Briefly...
>
> The tape contains a disk/tape backup/restore utility that is somewhat
> representative of those used with Point 4, and other 3rd-party DG lookalike
> systems. It is a stand-alone utility that is bootable if it exists as the
> first record of the first file of a mag tape or cartridge.
>
> The usual procedure is to bootstrap the tape using the Nova APL function
> (or just toggling in simple 2-instruction 'fat-finger' program). Once the
> program is read into memory, it starts execution and displays its
> introductory message. At this point another tape/cartridge may be loaded
> onto the tape drive for backup or restore purposes.
>
> I used our reNOVAte software for doing my investigations rather than SimH
> due to convenience, and was able to run the program and exercise its
> various functions. (Screen shots are attached.)
>
> This particular utility is very specific regarding the type of disk drive
> and IRIS logical units it supports.
>
> The utility assumes two devices exist: a tape controller using device code
> <022> and a disk controller using device code <027>. The tape controller
> may or may not perform QIC to DG-style file handling emulation since the
> original tape is not available to me.
> The disk controller appears to use the standard DG "Zebra" controller
> (Model 6060/6061/6067) programming model. However, it assumes a
> non-standard disk geometry of 16 cylinders, 5 heads, and 32 sectors.
>
> The tape file itself needs to be created in the SimH tape if it is to be
> used with the default SimH tape driver. The QIC format may exist as a
> single large data record of 16,384 bytes, or of multiple 512-byte records
> followed by a file mark. (I can not tell its original format given only the
> .bin file to work with.)
>
> The utility also makes assumptions about tape read timing and CPU
> instruction execution speed. Horrible programming technique, but
> unfortunately not uncommon practice. Any such timing dependencies must be
> found and compensated for in the device driver or instruction emulation.
>
> Since there is no disk backup tape to load onto the disk, I used dummy
> disk data for testing the disk-to-tape and tape-to-disk functions. Real
> backup tape(s) would obviously be needed to restore the original system.
>
>
> Bruce
>
>
>
> On 11/14/2015 3:35 PM, Microtech Dart wrote:
>
>> Thank you, Dell, and Sandy Strain, both of your responses were EXTREMELY
>> helpful to me, and these all worked!
>>
>> Do either of you have any additional thoughts about how I could make
>> what I believe to be a bootable file (extracted from a Microtech/Point4
>> QIC tape) into a bootable device for the Nova?
>>
>> I'll start with the Minicom Disk To Tape Utility:
>>
>>
>> http://microtechm1.blogspot.com/2015/09/minicom-disk-to-tape-copy-utility.html
>>
>> I've attached a .zip of the binary file that I extracted from this tape
>> for reference. It's very small, so I zipped it up only so that the
>> emailing process didn't interfere with or reject it.
>>
>> Thanks, all!
>>
>> -AJ
>>
>> On Sat, Nov 14, 2015 at 7:23 AM, Dell Setzer <dsetzer at panix.com
>> <mailto:dsetzer at panix.com>> wrote:
>>
>> It's actually pretty easy. After booting RDOS, press ^E to return to
>> the sim> prompt. Then, attach a host file to the MTA0 unit. If you
>> give a host filename that doesn't yet exist, SIMH will create an
>> empty tape file and attach it to MTA0:
>>
>> sim> attach mta0 testtape.tap
>> MTA: creating new file
>> sim>
>>
>> Then, give the simh G command to return to RDOS and init/f the MT0
>> tape unit. Note that at the sim> prompt, the unit is called "MTA0"
>> (or MTA1, MTA2, etc), while in RDOS the unit is called "MT0" (or
>> MT1, MT2, etc):
>>
>> sim> g
>> <presss return to get the RDOS prompt again>
>> R
>> init/f mt0
>> CONFIRM? <press Y to confirm>
>> R
>>
>> Now you can dump or copy files to the MT0 device:
>> dump/v mt0:0 -.sr
>> LITMACS.SR <http://LITMACS.SR>
>> OSID.SR <http://OSID.SR>
>> NSID.SR <http://NSID.SR>
>> PARS.SR <http://PARS.SR>
>> ALMSPD.SR <http://ALMSPD.SR>
>> <etc.>
>> R
>> dump/v mt0:1 -.sv
>> BURST.SV <http://BURST.SV>
>> INITIALIZE.SV <http://INITIALIZE.SV>
>> SEDIT.SV <http://SEDIT.SV>
>> MACXR.SV <http://MACXR.SV>
>> EDIT.SV <http://EDIT.SV>
>> <etc.>
>> R
>> release mt0
>> R
>>
>> After releaseing the tape, press ^E again to get to the sim> prompt
>> and detach the tape file:
>> ^E
>> sim> detach mta0
>> sim>
>> Now you can inspect the testtape.tap tape image.
>>
>> Attaching an existing tape file is similar, except that at the RDOS
>> prompt you'd do INIT rather than INIT/F:
>>
>> sim> attach mta0 testtape.tap
>> sim> g
>> R
>> init mt0
>> R
>> load/n mt0:0
>> LITMACS.SR <http://LITMACS.SR> 10/20/83
>> OSID.SR <http://OSID.SR> 01/10/84
>> NSID.SR <http://NSID.SR> 10/20/83
>> PARS.SR <http://PARS.SR> 01/31/85
>> <etc>
>> R
>> load/n mt0:1
>> BURST.SV <http://BURST.SV> 05/09/85
>> INITIALIZE.SV <http://INITIALIZE.SV> 05/02/85
>> SEDIT.SV <http://SEDIT.SV> 05/02/85
>> <etc>
>> R
>> release mt0
>> R
>>
>> Hope this helps,
>> ...dell
>>
>> On Sat, 14 Nov 2015, Microtech Dart wrote:
>>
>> Hi, I am completely new here, although I recognize the names of
>> several who
>> post here.
>>
>> I am trying to resurrect an extinct Microtech machine from 1982,
>> which
>> likely used the Point 4 processor, and the SimH DG Nova
>> simulator *should*
>> be compatible with the Point 4.
>>
>> I'm running the NOVA simulator now, with:
>>
>> NOVA simulator V4.0-0 Beta git commit id: 3be5125d
>> sim> ATTACH DKP0 *rdos_d31.dsk*
>> sim> set tti dasher
>> sim> boot DKP0
>>
>> I'm teaching myself RDOS now with the
>> RDOS_Command_Line_Interpreter Manual.
>> <
>> http://www.mirrorservice.org/sites/www.bitsavers.org/pdf/dg/software/rdos/093-000109-01_RDOS_Command_Line_Interpreter.pdf
>> >
>>
>> Would anybody here be able to suggest some methods by which I
>> could
>> *create* a magnetic tape device on this SimH Nova simulator, and
>> how I
>> might write some files to that?
>>
>> I think that would be an excellent experiment for me to
>> attempt. Then I
>> can inspect the binary file in a hex editor, and see what it
>> looks like,
>> then compare to the binaries I've pulled off my Microtech/Point
>> 4 tapes.
>>
>> --
>>
>> Thanks,
>> -AJ
>> http://MicrotechM1.blogspot.com
>>
>>
>>
>>
>> --
>>
>> Thanks,
>> -AJ
>> http://MicrotechM1.blogspot.com
>>
>>
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--
Thanks,
-AJ
http://MicrotechM1.blogspot.com
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