When it comes to Eight Edition, please don't forget Tom Cargill's
'pi'. There was also a version I believe that was used as the
debugger for programs on the Blit/Jerq; it seems to be known as
'4pi' in the source.
On Sat, May 2, 2020 at 6:49 AM Paul Ruizendaal <pnr(a)planet.nl> wrote:
Reading some more stuff about the road from 7th
Edition to 8th Edition,
this time about debuggers.
My current understanding is as follows:
- On 6th edition the debugger was ‘cdb’
- On 7th edition it was ‘adb’, a rewrite / evolution from ‘cdb’
- In 32V a new debugger appears, ‘sdb’. Its code seems a derivative from
‘adb’, but the command language is substantially reworked and it uses a
modified variant of the a.out linker format - in essence the beginnings of
‘stabs’. Of course the compiler, assembler, linker and related tools all
emit/recognize these new symbol table elements.
- The July 78 file note by London/Reiser does not mention a reworked
debugger at all; the 32V tape that is on TUHS has ’sdb' files that are
dated Feb/Mar 1979. This stuff must have been developed between July 78 and
March 79.
- In the SysIII and 3BSD code on TUHS (from early 80 and late 79
respectively) the stabs format is more developed. For SysIII it is ‘VAX
only’. With these roots, it is not surprising that it is also in 8th
Edition.
Two questions:
(1) According to Wikipedia the original author of the stabs format is
unknown. It also says that the original author of ‘sdb’ is unknown. Is that
correct, is the author really unknown?
(2) As far as I can tell, the ’sdb’ debugger was never back ported to 16
bit Unix, not in the SysIII line and not in the 2.xBSD line. It would seem
to me that the simple stabs format of 32V would have lent itself to being
back ported. Is it correct that no PDP11 Unix used (a simple) stabs tool
chain and debugger?