[Simh] Attach tar to tape device and access it from v7 in simh

[Johnny Billquist]

Repeat after me: tapes are not streams of bytes. See Clem's response for 
more detail. :-)

   Johnny

On 2017-11-07 20:58, Will Senn wrote:
> Hi,
> 
> I think I may have asked this a couple of years ago, but I am unable to 
> find the email conversation, so I'll ask it again from a position of 
> experience and greater but still lacking knowledge... here's the 
> background - I am running a v7 instance in simh that I am quite pleased 
> with. However, I saw somewhere where someone was running some additional 
> software on their instance and of course, I just had to have it for my 
> own. Unfortunately, it's not clear how they got the software, where it's 
> from, or how they got it running. There are hints that the stuff came 
> from early bsd. So... I thought I would try getting the bsd source on to 
> my v7 instance to see if I could compile it and play around with it. 
> There's a 1bsd.tar.gz in the tuhs archive. It being a tar file, I 
> figured I could:
> 
> gunzip 1bsd.tar.gz
> 
> in simh:
> 
> att mt0 1bsd.tar
> 
> in v7, which defaults to mt1 for some reason, (not a configured device 
> on my system and isn't created by make tm in /dev):
> 
> tar vxfb /dev/rmt0 1
> nboot.ini-13> boot rp0
> 
> Invalid magtape record length, PC: 002400 (MOV 177776,R0)
> 
> or
> 
> tar xv0
> 
> nboot.ini-13> boot rp0
> 
> Invalid magtape record length, PC: 002400 (MOV 177776,R0)
> 
> I don't know why the nboot.ini-13> boot rp0 artifact is appearing 
> (prolly some buffer flush when the sim aborts)... but of more concern is 
> why I can't access the tar. I'm sure it is a gap in my understanding, so 
> I'd appreciate some help.
> 
> Thanks,
> 
> Will
> 
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-- 
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