Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 4.3bsd-beta 6/6/85; site well.UUCP Path: utzoo!watmath!clyde!burl!ulysses!bellcore!decvax!decwrl!amdcad!lll-crg!lll-lcc!well!asgard From: asgard@well.UUCP (J. R. Stoner) Newsgroups: net.arch Subject: Re: PDP-8 Message-ID: <749@well.UUCP> Date: Tue, 11-Mar-86 01:29:36 EST Article-I.D.: well.749 Posted: Tue Mar 11 01:29:36 1986 Date-Received: Thu, 13-Mar-86 07:38:44 EST References: <187@anwar.UUCP> <1441@gitpyr.UUCP> <890@umn-cs.UUCP> <1468@gitpyr.UUCP> <307@ethz.UUCP> <2007@peora.UUCP> Reply-To: asgard@well.UUCP (J. R. Stoner) Organization: Whole Earth Lectronic Link, Sausalito CA Lines: 40 > [much heartfelt nostalgia about the PDP-8 instruction set] Ah yes, the PDP-8. At the tender age of 15 I was given the administrative duties over the PDP-8/E running in a math club lab at my high school. I really liked working with this machine as the instructions were simple to understand, although I never quite reconciled (sp?) myself with the addressing scheme of the machine. For instance, if I did not have PAL8 to do the hard stuff I would be *more* brain-damaged than I am now :-) All memory references outside a 128 word range were memory indirect, which took up one word out of the 128 and (you get the drift). This actually led to one of the nicest features of the PDP-8. You could specify an indirect bit for any of the memory operate instructions. My favorite game was to use a random number generator to specify an address for an ISZ I instruction to see how many memory cycles would run until the machine crashed (a high school game and I was the only user, so I got to have a lot of fun). My other fun is something I *never* figured out. Maybe somebody in netland would educate me as to the finer points. None of my programs ever exceeded the basic 4K core size. This was fine when running EDU-20. However, in later years we also got OS/8, which ran in an 8K system. I have not ever got the hang of how those funny IOT instructions for extra memory worked (I saw a lot of "CIF CDF 10" instructions in the disassembly of the CCL). As we had to switch from EDU-20 to OS/8 quite often and we did not have the autoload ROM I had the task of bit-flipping the OS/8 loader by hand every time for a switch (EDU was loaded by OS/8). I did that so many times that I can still recite the loader after 13 years. (Lets see... 7126 1060 6751 1061 4053 4053 7024 6755 ...) I mean that was *easy* and quite fun if you wanted to impress the frosh. -- From the mania of: J. R. (May the farce be with you) Stoner, Esq.