[TUHS] SDB debugger

Noel Hunt noel.hunt at gmail.com
Sat May 2 10:49:19 AEST 2020

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 at 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?
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