VT103 (was Re: Reviving DEC RX01 power supply)

Jerome Fine replies: Since I had never even heard of a DEC power strip, using insulated wire wrap seemed to be the best solution. The solder points stick out a bit. So stripping the wire about 1/8" was about right. Perhaps it was also prudent to pull the insulation back another 1/4" before soldering and then pushing the insulation forward again after making the connection and cooling off. I realize, but most everyone else reading this might not have a SCSI host adapter for the Qbus. I also have a SCSI host adapter for the Qbus and for a time it was the most costly Qbus board that I ever owned. over priced. On the other hand, for the VT103, the PDP-11/93 actually makes a lot of sense when you are looking at only 4 quad backplane slots and have an important project that needs 5 quad slots with a normal CPU and separate memory. But a BA23 box is not that much bigger and heavier if more than 4 quad slots are essential. As for the speed of the PDP-11/93, when I did buy one to sell to a customer over 10 years ago, I did a few benchmarks. For pure CPU speed, the PDP-11/93 is about 10% faster than the PDP-11/83 which agrees with the crystal of 20 MHz vs 10 MHz, respectively. However, the PDP-11/83 is only about 35% faster than the quad PDP-11/73 (M8190) which has a 15 MHz crystal and uses normal memory. Add PMI memory to the PDP-11/73 (almost all quad PDP-11/73 CPUs are able to handle this) and the speed difference is only about 15% - which means that the PMI memory speeds up a PDP-11/73 by about 20%. At one point, PMI memory demand was so low that it sold for less than normal Qbus memory. Shows what people really know. I have one which I would gladly trade if someone was truly interested in RT-11 software. Eventually I will need to abandon my collection, so ... Since E11 can also run on Linux, I should consider moving. For some of my work, speed is important - sieving for prime numbers. E11 is MUCH, MUCH faster than Simh. But maybe someone would be interested in a faster drive interface for Simh. The HD: drive under E11 would probably be ideal for emulation by Simh and that would mean the the RT-11 device driver would work under Simh as well. The interface is almost trivial. Does anyone want the details? Just add a hard drive and a DLV11-J with the M8186. With a quad M8189, you already have 2 serial ports. Probably best in that case to use the BA23 cabinet kit (if you have one) for the serial ports. Using the paddle board with an M8189 might be a problem since I seem to remember that the ports used with the paddle board did not use the baud rate selection on the DLV11-J but rather the baud rate was selected by the VT103. How many 4 MB Qbus memory cards do you have? Do you have any PMI Qbus memory cards? Christlen made a 4 MB PMI board, but by the time I became interested, it was not possible to justify the expense. Sincerely yours, Jerome Fine -- If you attempted to send a reply and the original e-mail address has been discontinued due a high volume of junk e-mail, then the semi-permanent e-mail address can be obtained by replacing the four characters preceding the 'at' with the four digits of the current year.