From mboxrd@z Thu Jan 1 00:00:00 1970 From: spedraja@gmail.com (SPC) Date: Thu, 15 May 2014 08:51:15 +0200 Subject: [TUHS] Unix on an 11/23 (Was: Work I've done with a PDP-11 simulator) In-Reply-To: <20140515004132.88ADF18C101@mercury.lcs.mit.edu> References: <20140515004132.88ADF18C101@mercury.lcs.mit.edu> Message-ID: Great work, Noel. A lot of thanks (to you but for the rest of helpers too). I'll keep a reference of this message and try it as soon as possible... the disruptive fact (in terms of time) here is to put up-to-date both the PDP-11/23-PLUS and RL02. Once I do that will embark on your hack. Gracias | Regards - Saludos | Greetings | Freundliche Grüße | Salutations ​ -- *Sergio Pedraja* -- mobile: +34-699-996568 twitter: @sergio_pedraja | skype: Sergio Pedraja -- http://plus.google.com/u/0/101292256663392735405 http://www.linkedin.com/in/sergiopedraja http://www.quora.com/Sergio-Pedraja http://spedraja.wordpress.com https://www.xing.com/profile/Sergio_Pedraja ----- No crea todo lo que ve, ni crea que está viéndolo todo 2014-05-15 2:41 GMT+02:00 Noel Chiappa : > >> I got one PDP-11/23-PLUS without any kind of disk (by now, I got one > >> RL12 board plus one RL02 drive pending of cleaning and > arrangement)... > >> I guess if could be possible to run V6 in this machine. There's any > >> kind of adaptation of this Unix version (or whatever) to run under ? > > > IIRC the README page for that set of disk images indicates that in > fact > > they originally came off an 11/23, so they should run fine on yours. > > So I was idly looking through main.c for the Shoppa Unix (because it > printed > some unusual messages when it started, and I wanted to see that code), and > I > noticed it had some fancy code for dealing with the clock, and that > tickled a > very dim memory that LSI-11's had some unusual clock thing. So I decided I > had better check up on that... > > I got out an LSI-11 manual, and it looked like the 23 should work, even for > the 'vanilla' V6 from the Bell distro. But I decided I had better check it > to > be sure, so I fired up the simulator, mounted a Bell disk, set the cpu type > to '23', and booted 'rkunix'. Which promptly halted! > > After a bit of digging, it turned out that the problem is that the 11/23 > doesn't have a switch register! It hit a kernel NXM trying to touch it - > and then another trying to read it in the putchar() routine trying to do a > panic(), at which point it died a horrible death. > > So I added a SR (you can create all sorts of bizarre hybrids like that with > Ersatz-11, like 11/40's with 11/45 type floating point :-), and then it > booted fine. The clock even worked! > > > So you will have to use the Shoppa disk to boot (but see below), or we'll > have to spin you a special vanilla V6 Unix that doesn't try to touch the > SR - > that shouldn't be much work, I only found two place in the code that touch > it. > > I did try the Shoppa 'unix', and it booted fine on an 11/23. > > Two things to check for, though: first, your 11/23 _has_ to have the MMU > chip > (that's the large DIP package with one chip on it nearest the edge of the > card), so if yours looks like this: > > http://www.psych.usyd.edu.au/pdp-11/Images/23.jpeg > > you're OK. Without the MMU chip, most variants of Unix will not run on the > 23 > (although there's something called MiniUnix, IIRC, which runs on an LSI-11, > which would probably run on a /23 without an MMU). > > > Here's the part that might be a problem: To run any of the Unixes on the > Shoppa disk, you also have to have the FPP chip too (that's the second > large > DIP package with two chips on it - the image above does not include that > chip, so if yours looks like that, you have a minor problem, and I will > have > to build you a Unix or something). > > All of the Unixes on the Shoppa disk have to have the FPP, except one - and > that one wants an RX floppy as the root/swap device! The others will all > crash (I tried one, to make sure) if you try and boot them on an 11/23 > without the FPP. > > I could try patching the binary on the one that doesn't expect to use the > FPP > to use the RL as the root, or either i) build you a vanilla V6 for a 23 > (above), or ii) figure out how to build systems on the Shoppa disk, and > build > you a Unix there which i) uses the RL as the root/swap, and ii) does not > expect to have the FPP. > > But let's first find out exactly what you have... > > Noel > -------------- next part -------------- An HTML attachment was scrubbed... URL: