PDP-8 VT8-E

For the PDP-11 Qbus environment, DEC produced a VT100 with a 4 x 4 Qbus backplane inside and named it the VT103. The 4 x 4 Qbus backplane was serpentine ABAB and able to hold 4 quad cards or 8 dual cards or any compatible mixture. Unfortunately, the 5 volts was limited to 16 amps - INCLUDING what the VT100 used as well, so there was really insufficient power to a full set of cards, in particular an RQDX1 or an RQDX2. However, at one point, I did test out with a quad M8190-AB, a 4 MB quad memory card, a dual DHQ11 and a dual CQD 220M/T host adapter. So there was still one quad slot empty. I presume that a PDP-11/93 CPU card could be used instead which would have added 7 DL ports and eliminated the quad 4 MB memory card leaving TWO quad slots empty. BUT I did not have the PDP-11/93 card at the time. Of course, all of the SCSI disk drives (including a Sony SMO S-501 for backup and recovery) were powered by an additional external power supply. At this point, if I were to repeat the test, I would use AT LEAST FIVE DEC 2 GB RZ28D-E SCSI hard drives (plus the magneto optical drive for disk storage) which would certainly be substantial enough disk storage and backup for almost any PDP-11 application. I was also tempted to at least add a DLV11-J to be able to activate one of those ports for a hard copy printer (DECwriter 3) that would have used the back of the VT100 portion DB25, but there really was no point. The point of the above information is that DEC seems to have used some of the popular (at the time) terminals to be integrated as combination terminal and popular PDP (Program Data Processor - after all, they were never :-) actual computers) systems. In the case of the PDP-11, the power of the system could at least equal anything that DEC ever produced, although the options might be a bit limited. Jerome Fine