Mark, Rare - probably depends on where you can look! :-) RT-11 will run on any of the PDP-11's. The RSX-11 family of OS's has specific requirements about memory amounts and memory management thus the SPD should be reviewed. RSTS/E (and M+) require memory management hardware. If you can find one, the best is probably the 11/73, 11/83 or 11/93 in a BA23 (QBUS) enclosure. These come in either 4, or 8-slot backplanes. If you really want to experience pain in your electric bill then the BA123 (also QBUS) with it's 645 watt dual power supplies can double as a winter heater/loud white-noise generator. These come in a 12 slot backplane configuration. The Pro-Series of systems could also be looked at for RT-11 and RSX (P/OS). In this space the Pro-380 is probably preferred. The problem here is finding a network card (DECNA) that does not cost as much (or more) than the rest of the system. Disks on real hardware will be small and slow (an possibly expensive). On emulated systems they can be much bigger and many many times faster. The books you have detail the degree of expandability for each of these HW platforms (except maybe the Pro). You will be surprised at just how much can be done with these systems. The speed will be another story. All of these machines have some weight to them. An emulator will be much faster and in the end easier to deal with. When the PLUTO:: machine is running as an emulated machine it is running with NetBSD and SimH on a 700MHz Pentium-III, otherwise it is a real PDP-11/23+ (22-bit backplane). The emulated machine is faster than the real thing, but not my much. I was going for similar performance so that when I switch between the two it wasn't that noticeable/painful to return to the actual hardware. PLUTO:: configuration (from memory) BA23 backplane (8-slot version) PDP-11/23+ 4MB memory FPU chip set (somewhat rare these days) CIS chip set (extremely rare these days) 2 * RQDX3 controllers - 1 for RD54 and dual RX50 drives (internal) and 1 for RD5x drive (external) KLESI controller (TK50 tape drive (external) DELQA NIC 2 serial ports (on main CPU board) 4 serial ports (on DHQ11 board) RT-11 Languages (from memory): MACRO-11 APL-11 BASIC-11 MU/BASIC-11 BASIC-PLUS/RT-11 FORTRAN-IV (FORTRAN 66 STD) PDP-11/C DECUS-C RSX-11 Languages (also from memory): MACRO-11 APL-11 BASIC-PLUS-2 FORTRAN-IV (FORTRAN 66 STD) FORTRAN-77 PDP-11/C DECUS-C COBOL-81, COBOL-11 RSTS/E Languages (also from memory): The same as RSX-11 for the most part. If you want to have a look around RSTS/E, I can create an account on PLUTO:: for you to poke around. Just let me know off-list. -Steve -----Original Message----- From: owner-hecnet at Update.UU.SE [mailto:owner-hecnet at Update.UU.SE] On Behalf Of Mark Wickens Sent: Thursday, July 14, 2011 15:50 To: hecnet at Update.UU.SE Subject: Re: [HECnet] PDP Ignorance Are the MicroPDPs (desktop, deskside, rackmount) rare beasts? They seem to be of a fairly hobbyist-friendly size, although presumably they are less expandable (much like a VAXstation versus VAXserver I would imagine) Mark.