Re: Object-relational impedence

"David Cressey" <cressey73_at_verizon.net> writes:
> I don't think of 1971, when I wrote the garbage collector for MDL as "the
> early days of garbage collection." The "early days would have been in the
> 1950s when McCarthy wrote the garbage collector for LISP. The MDL garbage
> collector was more ambitious than the Lisp garbage collector. But I had the
> advantage of learning from the work that had already been done.

apl also did new storage allocation on every assignment ... and did garbage collection & compaction when space in workspace was exhausted.

the science center (4th flr of 545 tech sq) http://www.garlic.com/~lynn/subtopic.html#545tech

ported apl\360 to cp67/cms ... and had to rework the garbage collection. typical apl\360 workspace was 16kbyte-32kbyte real storage ... and whole workspace was always swapped as single unit.

cms allowed for multiple mbyte (virtual memory, paged) workspaces ... and the apl\360 garbage collection implementation resulted in severe page thrashing ... which had to be redone for virtual memory environment before release of cms\apl.
http://www.garlic.com/~lynn/subtopic.html#hone

part of work on apl virtual memory garbage collection used some application monitoring and modeling tools also done at the science center ... which was eventually released as vs/repack product in the mid-70s (included semi-automated program reorganization for virtual memory operation).

vs/repack technology was used by a number of internal product groups (including varioud dbms like IMS) as part of transition from real storage to virtual storage environment.

the followon to cp67, vm370 was used (originally on 370/145 in bldg. 28) for the original relational/sql implementation, system/r http://www.garlic.com/~lynn/subtopic.html#systemr Received on Tue Mar 11 2008 - 03:02:57 CET