dmr@alice.att.com (Dennis Ritchie) (02/14/91)
Roy Smith wondered about how to look at v6, which exist on tape as RK05 disk images. Here's how we do it. It's instructive of something--I'm not sure quite what, but it makes an interesting demo, and it is a useful way to keep these archives. We transferred the disk images to big single files. Norman Wilson wrote a file server that understands the v6 disk format (512-byte disk blocks, 32-byte inodes, 16-bit disk addresses). Thus we can mount this disk image as a file system and poke around in it. Incidentally, we still have a few vax 11/750s, with the pdp-11 compatibility feature. So, from such a machine I can do cd /n/bowell/usr/src/history/v6/bin/bin # move to v6 /bin compat sh # start v6 shell and get a `%' prompt. These commands change to a directory on another machine, which contains an interpreted Sixth Edition file system, and run the Sixth Edition shell. Many of the commands there work. E.g. % ./size sh 4992+880+1408=7280 (16160) % ./date Thu Feb 14 00:46:32 EST 1991 % ./dc 10k2vp 1.4142135623 Doing this induces a somewhat creepy feeling. Dennis Ritchie dmr@research.att.com att!research!dmr
dik@cwi.nl (Dik T. Winter) (02/15/91)
We did not (yet) receive the parent article, so I do not know what the exact question was, but ... In article <11872@alice.att.com> dmr@alice.att.com (Dennis Ritchie) writes: > Roy Smith wondered about how to look at v6, which exist on tape as > RK05 disk images. Here's how we do it. It's instructive of > something--I'm not sure quite what, but it makes an interesting demo, > and it is a useful way to keep these archives. What I did do a long time ago was to write a program that would look at the disk image on file and convert it to a complete directory structure. The trick is to find inode #2 and start from there. I do not know, but perhaps, if I look long enough in my archives, the program might even be sitting somewhere. > > We transferred the disk images to big single files. Norman Wilson > wrote a file server that understands the v6 disk format (512-byte disk > blocks, 32-byte inodes, 16-bit disk addresses). Thus we can mount > this disk image as a file system and poke around in it. This is of course far superior. -- dik t. winter, cwi, amsterdam, nederland dik@cwi.nl
jfh@rpp386.cactus.org (John F Haugh II) (02/19/91)
In article <2945@charon.cwi.nl> dik@cwi.nl (Dik T. Winter) writes: >What I did do a long time ago was to write a program that would look at the >disk image on file and convert it to a complete directory structure. The >trick is to find inode #2 and start from there. I do not know, but perhaps, >if I look long enough in my archives, the program might even be sitting >somewhere. The v7 and v6 filesystems are very different. While the v7 filesystem has been described at great length in literature, I've never seen anything describing the v6 filesystem in any published document that can be repeated without violating licensing agreements. For example, the root inode in a v6 filesystem is inode 1 ... -- John F. Haugh II UUCP: ...!cs.utexas.edu!rpp386!jfh Ma Bell: (512) 832-8832 Domain: jfh@rpp386.cactus.org "I've never written a device driver, but I have written a device driver manual" -- Robert Hartman, IDE Corp.