[TUHS] SDB debugger
clemc at ccc.com
Mon May 4 02:13:09 AEST 2020
On Sat, May 2, 2020 at 4:16 PM Paul Ruizendaal <pnr at planet.nl> wrote:
> The dbx debugger appears to stand on the shoulders of sdb, and gdb on the
> shoulders of dbx.
Mumble ... It's true rms started with dbx and peed on it in their
usually way - similar to the Gosling EMACS to GnuEMACS story.
But Mark wrote DBX from scratch, although I would be surprised if looked
at how adb and sdb handled the symbol table and could have lifted that code
from their. If I remember discussions with him about it, his interface
model was really more VMS debugger more than sdb. As I said, I really
don't remember anyone at UCB in those days using sdb.
At the time, there was a huge push (mostly from the Stanford crew) to make
VMS the Arpa standard system replacing the PDP-10, TOPS, Tenex, ITS, et
al. Besides the performance argument (hence the 4.1 FASTVAX work), one of
the arguments from the pro-VMS side was the language toolchain, including
comments that UNIX did not have a debugger in the same vein as VMS (and
also that the Fortran system was considered pretty weak).
When he was still at UCB, Mark had tried to make sure dbx worked with both
C and Fortran (i.e. at the beginning of the project I did some testing for
him because I was working on a large array processor in the CAD group, that
needed to compile EE CAD suite which at that point was heavily dominated by
Fortran codes). The whole BSD UNIX Fortran was not great and I know when
Masscomp built their debugger, they started with dbx and had to gut the
multiple language support (thus rewriting much of the Fortran & Pascal
support); but the person that did it, had been part of DEC's TLG team
previously and had a direct knowledge of how the DEC debugger actually
handled multiple languages. BTW the time, I personally did not really
care, as long as C support worked.
Paul W -- do you remember if DEC TLG did a version of dbx for Ultrix
(Leslie might remember)? FWIW: I know that DEC had a number of different
debugger projects so on the UNIX side over the years, and I really don't
remember what was done for the VAX, as I was not there at the time. By
MIPS/Alpha in the mid-late 90's there was a whole new debugger stream that
had been developed at part of GEM, but there was another one that came from
MIPs too which was based on dbx.
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