[HECnet] BRU tapes, extract on UNIX?

[Johnny Billquist]

On 2015-03-16 18:32, Clement T. Cole wrote:
Yes. It should be by easy to do,   although I thought Tom put the BRU support code in there because I remember one the folks we worked (Mital in Canada IIRC) used RSX somewhere and he had the deal with it when then sent us tapes.   But may be it was not BRU.   I don't remember as that worked started as I was leaving UCB and Tom had become the new mr. 9-track and Thus I did not write that code (I did write the original RT11 support with which he started).

I obviously don't know what Tom might have done. It's definitely possible he did. But depending on when this was, it might have been another format called DSC (Disk Save and Compress), which is what RSX used up until V3.something. Which is, I think, almost mid-80s.
BRU has been documented enough that it's not hard to write a program to extract the files from it, but it's is not totally trivial, as the files are somewhat scrambled in the saveset. I wrote a program to analyze and manipulate BRU tapes under Unix, to be able to repair tapes that had become corrupted (tape blocks scrambled).

When Tom took over   he wrote a whole new program because the CAD group had had to start to deal with VMS so much and my original ANSI reader for RT11 tapes was pretty lame.       When he was done, I'm pretty sure he could handle VMS save sets in his version because that what the CAD group @ DEC would use.   I remember that HP used some funky format from the HP3000 which I ended up decoding using dd and some shell scripts and when never used again as we got them to switch to tar.   IBM was always a different format (usually in EBCDIC).   I remember once getting an ANSI labeled tape from them but in EBCDIC and broke all our tools.   AT&T could also be funny.   Different groups there used different tools even within UNIX so I got pretty good handling strange formats since they often sent tapes in binary and had endianness mixed in to add to the confusion. At the time, I   became the go to person in Cory Hall (and often Evans folks would come to see me too) because I had spent time in a mainfra
m
e shop long before UCB and learned a lot of tricks and had a tool kit for same.

VMS backup savesets are totally incompatible with BRU savesets, though (sad). But I know I've seen Unix tools to read VMS tapes and savesets.

But both VMS and RSX use normal ANSI format tapes, so the first level of just getting to the savesets as such, is easy on Unix. Plenty of tools already exist to deal with ANSI labelled tapes.

	Johnny

Somewhere I have a script called mtaapita   - mag tapes are a pain in the ass - which I wrote to help pull the first few records apart and try to figure out how the tape was formatted.   As I said, I used to have a pretty good collection of mag tape tools but they are not online anymore ( undoubtedly on a 9-track Unix dump tape in my basement).

Sent from my iPad

On Mar 16, 2015, at 12:25 PM, Johnny Billquist <bqt at softjar.se> wrote:

On 2015-03-16 14:08, Clem Cole wrote:
The format is defined in:
http://www.ibiblio.org/pub/academic/computer-science/history/pdp-11/rsx/decus/rsx86a/301050/bruformat.txt
and yes UNIX has tools that grok it.

Worst case it any ANSI tape reader will get the raw data off as files
with strange names and you may need a shell script to put some of the
files back together after decoding the directory.

My old housemate (and SPICE2/3 author) Tom Quarles wrote an really good
ANSI tape reader for Unix years ago. It did VMS format by default but
seem to remember he added RT11 and RSX support to it also.   Since we had
to write tapes to export to those systems also.

Sadly, I used to have a directory of "magtape utilities" but I no longer
have it online.     I'll try to poke around to see if I can find it next
weekend if no one else shouts out sooner.

BRU tapes are proper ANSI format tapes, so as far as that goes, the whole saveset as such can certainly be accessed with any tool that deals with ANSI tapes.

However, BRU savesets is another level, below this. To extract files from those savesets will require other software. I don't think any exists for Unix, but you can certainly write it.

      Johnny


Clem



On Mon, Mar 16, 2015 at 1:05 AM, Cory Smelosky <b4 at gewt.net
<mailto:b4 at gewt.net>> wrote:

      All,

      Is it possible to extract files from a BRU RSX tape on UNIX, or is
      the best path BRUREAD to VMS, and then zip/tar?

      --
      Cory Smelosky
      http://gewt.net Personal stuff
      http://gimme-sympathy.org Projects



-- 
Johnny Billquist                                   || "I'm on a bus
                                                                  ||   on a psychedelic trip
email: bqt at softjar.se                         ||   Reading murder books
pdp is alive!                                         ||   tryin' to stay hip" - B. Idol