On Sat, May 2, 2020 at 4:16 PM Paul Ruizendaal <
pnr@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.
Clem