TUHS January 2019

tuhs@tuhs.org

67 participants
52 discussions

Re: [TUHS] Upgrading from 11/40 to 11/45 in Unix v6

by jnc＠mercury.lcs.mit.edu

> From: Will Senn > We are seriously considering upgrading our PDP 11/40 clone (SIMH), to a > PDP 11/45 (preferably another SIMH) Heh! When I saw the subject line, I thought you wanted to upgrade a _physical_ -11/40 to an -11/45. ('Step 1. Sell the -11/40. Step 2. Buy an -11/45.' :-) > for our Unix v6 installation. Why on earth would an organization have such a thing? :-) > Our CEO was traveling and met a techie in first class (seriously, > first class?) who told him that we needed one. Heh. If said techie knows about the two, he's probably pretty senior (i.e. eligible for Social Security :-), and thus elegible for first class... :-) > It has fairly low utilization - a developer logs in and writes code > every few days Who the *&%^&*(%& is still writing code under V6?! And how do you all get the bits in and out? (I run mine under Ersatz-11, which has this nice device which allows it to read files off the host file system; transfering stuff back and forth is a snap, I do all my editing with Epsilon on my Windoze box, 'cause I'm too lazy to bring up the V6 Emacs I have.) > 1. Are there any v6 specific concerns about upgrading? Not that I know of. > 2. Why should we consider taking the leap to the 11/45? Everything > seems to work fine now. You're asking _us_? Some larger applications will only run on an split-I-D machine, is about the only reason I can think of. Oh, also, the floating point instructions on the /45 are the only kind understood by V6; the C compiler doesn't emit the ones the /40 provides. Any floating point code run on the /40, the instructions are simulated by a trap handler (by way of the OS, which has to handle it and reflect it to the user process). I.e. very slow. > 3. If we jump in and do the upgrade, how can we immediately recognize > what has changed in the environment? I.e what are some things that we > can now do that we couldn't do before? See above. > 4. If we just insert our current diskpacks into the new system, will it > just boot and work? Or what do we need to before/after booting to > prepare/respond to the new system? Any V6 disk pack can be read/mounted on any V6 machine. Any binaries (the OS, or user commands) for the -11/40 will run on the -/45. (Which is why the V6 dist includes binaries for /40 versions of the OS only.) To make use of the /45, you need a different copy of the OS binary, built from a slightly different set of modules. (Replace m40.s with m45.s; and you will need to re-asssemble l.s, prepending it with data.s.) Both variants can live on the same pack, under different filenames; select the right one at boot time. > 5. Is 256K enough memory or what configuration do y'all recommend? 256KB is all you can have. Neither SIMH nor Ersatz-11 support the Able ENABLE: http://gunkies.org/wiki/Able_ENABLE which is what you need to have more than 256KB on a UNIBUS -11. > From: Clem Cole > You'll probably want to configure a kernel for the 45 class machine. > Look at the differences in the *.s files in the kernel. More importantly, look at the 'run' file in /usr/sys, which has commented out lines to build the OS image for /45-/70 class machines. > But either way you should configure the system to use the largest drive > v6 has. This is actually of limited utility, since a V6 file system is restricted to 65K blocks _max_. So a disk with 350K blocks (like an RP06), you'll have to split it into like 5 partitions to use it all. > From: Will Senn > Do you know of some commonly used at the time v6 programs that needed > that much space? Heh. Spun up my v6, and did "file * | grep separate" in /bin and /usr/bin, and then recalled that V6 was distributed in a form suitable for a /40. So, null set. Did the same thing on /bin from the MIT V6+ system, and got: a68: separate I&D executable not stripped a86: separate I&D executable not stripped bteco: separate I&D executable not stripped c86: separate I&D executable not stripped e: separate I&D executable not stripped emacs: separate I&D executable not stripped lisp: separate I&D executable not stripped mail: separate I&D executable not stripped ndd: separate I&D executable not stripped s: separate I&D executable not stripped send: separate I&D executable not stripped teco: separate I&D executable not stripped No idea what the difference is between 'teco' and 'bteco', what 's/send' do, etc. > Is there any material difference between doing it at install time vs > having run on 11/40 for a while and moving the disk over to the 11/45 > later? No; like I said, you can have two different OS binaries on the disk, and select which one you boot. > On a related note, how difficult is it to copy the system from rk to > hp? I know I can rebuild, but I'm sure there's a quicker/easier method... Build a system with both, and then copy the files? I'd use 'tar' (I have a V6 tar, but it uses a modified OS with the smdate() call added back in) to do the moving (which would retain the last-write dates); 'tp' or 'stp' would also work. The hack _I_ used on simulated systems was to expand the file that held the 'disk pack', mount it as a different kind of pack (RL or RP), and then go in and hand-patch the disk size in the root block with 'db', then 'icheck -s' to re-build the free list. Note: this won't give you more inodes, so you may run out, but the usual inode allocation is pretty generous. Noel PS: Speaking of the last write dates, I have versions of mv/mvall, cp/cpall, ln, chmod etc which retain them (using smdate()). If there's an actual community of people using V6, I should upload all the stuff I have. Although it might be good to establish some central location for exchange of V6 code. However, I don't and won't (don't even ask) use GitHub or any similar modern thing.

5 years, 12 months

building world using sh run in /usr/source in v6

by Will Senn

The setting up document hints at how to build world so to speak in v6. However, when I log in as bin (most files are owned by bin) and: chdir /usr/source sh run I get a number of failed items along these lines: cp a.out /etc/cron Can't create new file. cp a.out /etc/init Can't create new file. A little digging around points to the problem - some files are owned by daemon, others by root: -rwsrwsr-- 1 daemon 3246 Oct 10 12:54 cron -rwxrwxr-- 1 root 2054 May 13 23:50 init My question is this, is the system recompiled en-masse using the run script in /usr/source or not? It certainly appears to be the method, as it contains a bunch of chdir somedir; time sh run lines including the /usr/sys/run file... If it's not, what was the method? I gather I can force it by logging in as root and running those sections of the run script pertaining to files owned by root, and the same for daemon, but that seems inefficient and begs the question why didn't they have run scripts for root and daemon that were separate from the ones for bin. Thanks, Will -- GPG Fingerprint: 68F4 B3BD 1730 555A 4462 7D45 3EAA 5B6D A982 BAAF

5 years, 12 months

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TUHS January 2019