PDP-11/05 returns to life

Jerome Fine replies: First, you can use an RX02 drive to produce bootable RX01 bootable floppy media, but there are some details which are unusual. Ask if that ability could be useful. Second, there are probably PC compatible RX01 drives which would allow SIMH to directly produce an RX01 bootable floppy media. Since I have no experience with 8" floppy drives on a PC, I can't help at all. An RX02 floppy drive on a PC is also possible as far as I have heard, but a Catweasal controller is needed, as far as I know. Again, I don't know any of the details and it is possible that only Ersatz-11 supports an RX02 floppy on a PC. As for which version of RT-11, RT11XM can't be run on a PDP-11/05 since there is no memory management hardware, aside from the requirement that there be at least 32 KWords or 64 KBytes of physical memory. V04.00 is a reasonable version of RT-11 to run on a PDP-11/05. I would suggest that you use RT11FB if you are doing anything extensive since RT11SJ performs a RESET after each command - which really slows things when a floppy is used. V05.03 with RT11FB is a very nice version of RT-11, but uses a bit more memory then V04.00 which may be a problem with only 16 KWords. However, the extra RT-11 features are probably worth the extra memory. You can run all of those versions of RT-11 under SIMH and check for yourself which seems most suitable. Since both the RT11SJ and RT11FB monitors use 56 KBytes under SIMH (rather than 64 KBytes since the top 8 KBytes are reserved for the IOPAGE registers), just subtract 24 KBytes of memory from what the background job has available and you will know what to expect on the PDP-11/05. Under V05.03 of RT-11, the command is: SHOW MEMORY (or just SH M) If you have any other RT-11 questions, just ask, especially to help with setting up a boot RX01 floppy media. A V05.03 distribution of RT-11 is available for download to be run under SIMH. at: http://www.classiccmp.org/PDP-11/RT-11/dists/ Sincerely yours, Jerome Fine