Atlas was represented at this meeting by L O Ford and I Buchanan.
Due to inadequate publication of this event by DECUS, the attendance was unfortunately low, being limited to representatives from Birkbeck, Imperial College and ourselves on the users' side and both members of the PDP15 software support team from DEC plus the DECUS secretary.
In spite of the low numbers the 2-hour meeting provided a forum for an interesting and often lively discussion of those aspects of the PDP15 of interest to the group.
Some time was spent discussing the problems of the Unichannel with special reference to the Birkbeck machine which we saw briefly after the meeting.
Of more interest to us was the news that the new XVM/DOS software, due for release in February 1976, will in the future be the only supported software on the PDP15. Some features of this software are listed below:
(1) central monitor completely rewritten, dispensing with all PDP9 compatible code
(2) batch jobs allowed from any device; this will alleviate the problem of 1 FORTRAN subroutine = 1 file and will enable us to use FASTEX, with the overlay description being read from the disc as in XCHAIN
(3) XVM/DOS software does not require XVM hardware
(4) XVM/DOS has sync on, which will protect the phosphor from the very bright ^ symbol on an otherwise clear screen
The use of other languages on the PDP15 was discussed, specifically ALGOL and CORAL. An ALGOL compiler, produced unfunded by DEC Europe, and not supporting floating point representation, is available from DEC and RRE have a CORAL compiler, written by a software firm. LOF asked for the approximate price.
The use of RSX as a multi-user system was a topic which was raised by Imperial and ourselves. We were informed that Alan Reid of UKAEA Preston had achieved this reasonably simply by making duplicates of system programs eg EDIT, FORTRAN which have specific assignments of logical unit numbers corresponding to the device from which they are run. This approach has obvious drawbacks but seems to be the only one possible. A true multi-user system may be written by DEC after XVM is released but this project could be set aside in favour of further software development for the use of the Unichannel.
The next meeting of the group is on Tuesday, 16 December, at Birkbeck College.
