All,

In my exploration of v6, I followed the advice in "Setting up Unix - Seventh Edition" and copied v6tar from v7 to v6. Life is good. However, tar is using mt1 and it is hard coded into the source, tar.c:
char    magtape[]       = "/dev/mt1";

As the subject line suggested, I have two questions for those of you who might know:

1. Why is it hard coded?
2. Why is it the second device and not the first?

Interestingly, it took me a little while to figure out it was doing this because I didn't actually move files between v6 and v7 until today. Before this my tests had been limited to separate tests on v6 and v7 along the lines of:

cd /wherever
tar c .
followed by
tar t
list of files
cd /elsewhere
tar x
files extracted and matching

What it was doing was writing to the non-existant /dev/mt1, which it then created, tarring up stuff, and exiting. Then when I listed the contents of the tarfile, or extracted the contents, it was successful. But, when I went to move the tape between v6 and v7, the tape (mt0) was blank, of course. It was at this point that I followed  Noel's advice and "Used the source", and figured out that it was hard-coded as you see above.

Thanks,

Will
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