On Thu, 1 May 2008, Brad Parker wrote: Ahh, that makes sense. So if we build with the 1ed "as" then those first few lines should be commented out since they will be occupied by the a.out header. Ahh! yess, it makes sense, e00-02 has a section at orig+400 "copy in transfer fectors" where those vectors are overwritten during startup. We really should try building with the 1ed assembler. I think a simple sed s/mount/xmount/ over the whole sources will probably fix the mount label issue. Tim Newsham http://www.thenewsh.com/~newsham/

added tools/assem which builds using the 1ed "as". Tim Newsham http://www.thenewsh.com/~newsham/

Brad Parker scripsit: Note that the whole point of the magic number being what it is, is that it's a PDP-11 unconditional branch instruction to skip the rest of the header. That way the a.out file could be loaded header and all and just started at its beginning by jumping into it. -- Samuel Johnson on playing the violin: John Cowan "Difficult do you call it, Sir? cowan(a)ccil.org I wish it were impossible." http://www.ccil.org/~cowan

On Thu, May 01, 2008 at 01:47:33PM -0400, Brad Parker wrote: I managed to scan in the 2nd Edition manuals, and they are available as a PDF here: http://minnie.tuhs.org/Z/2ndEdManuals/unix_2nd_edition_manual.pdf [ That URL is guaranteed to be ephemeral; Al, could you copy it to bitsavers? ] The skew on some of the pages comes from the photocopy that I have. Apologies. 1st Edition a.out headers were 0405, 12 bytes long. 2nd Edition a.out headers were 0407, 14 bytes long. In terms of the userland binaries we have from this era (on the s2 tape at http://www.tuhs.org/Archive/PDP-11/Distributions/research/1972_stuff/s2-bit…), some binaries are 0405 and others are 0407. Here are the 0405 ones: bin/: bin/mv bin/ar bin/od bin/bas bin/pr bin/cat bin/rew bin/chball bin/rmdir bin/check bin/roff bin/chown bin/sh bin/cmp bin/skip bin/cp bin/sort bin/date bin/stat bin/db bin/stty bin/dc bin/su bin/df bin/sum bin/du bin/tap bin/echo bin/tm bin/ed bin/tty bin/exit bin/wc bin/form bin/who bin/goto bin/write bin/if etc/getty bin/login etc/glob bin/ls etc/init bin/mail etc/msh bin/mesg etc/suftab bin/mkdir Here are the 0407 ones: bin/as usr/fort/fc1 bin/cc usr/fort/fc2 bin/ds usr/fort/fc3 bin/fc usr/fort/fc4 bin/find usr/jack/a.out bin/ld usr/jack/x.o bin/maki usr/lib/c0 bin/nm usr/lib/c1 bin/size usr/lib/crt0.o bin/strip usr/lib/fr0.o bin/un usr/sys/a.out etc/as2 As you can see, as and as2 are 0407, hence they are V2 binaries, and so would be likely to output the V2 header. I haven't read the the OCR'd kernel source fully yet; in the section for exec(), there must be code to parse an a.out header. Does it only know about 0405, or 0407, or both? Hope this helps, Warren

On Thu, May 01, 2008 at 08:34:10AM -1000, Tim Newsham wrote: Tim, I think the as we have from the s2 tape is a V2 assembler, as it has an 0407 header, not an 0405 header. Patching the V2 as binary to work like V1 is going to be hard. I even though about modifying the V7 as to output 0405 headers, but again hard. Given that we know the assembler has predefined symbols, which means renaming $mount, I think we might as well take the path where we modify the source code so that it can be built with the tools we have, which is your option 2) above. And of course, document the changes. Cheers, Warren

On Thu, 2008-05-01 at 14:18 -0700, Al Kossow wrote: Great! Many thanks for that. Hellwig