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* [TUHS] Upgrading from 11/40 to 11/45 in Unix v6
@ 2018-12-31  2:25 Will Senn
  2018-12-31  2:43 ` Clem cole
  2018-12-31  2:47 ` [TUHS] Upgrading from 11/40 to 11/45 in Unix v6 Clem cole
  0 siblings, 2 replies; 27+ messages in thread
From: Will Senn @ 2018-12-31  2:25 UTC (permalink / raw)
  To: tuhs

Dear Unix Enthusiasts,

We are seriously considering upgrading our PDP 11/40 clone (SIMH), to a PDP 11/45 (preferably another SIMH) for our Unix v6 installation. Our CEO was traveling and met a techie in first class (seriously, first class?) who told him that we needed one. I thought I had better ask some folks who have gone before about it before we jumped on the bandwagon. By way of background, Our install is pretty small with a few rk’s and 256K of ram along with a few standard peripherals, and some stuff our oldtimers refuse to part with (papertape, card punch, etc). It has fairly low utilization - a developer logs in and writes code every few days and the oldtimers hunt the wumpus and play this weird Brit game about cows. It could be considered a casual development and test environment and an occasional gaming console.

Here is what I would like to know that I think y’all might be particularly equipped to answer:

1. Are there any v6 specific concerns about upgrading?

2. Why should we consider taking the leap to the 11/45? Everything seems to work fine now.

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?

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?

5. Is 256K enough memory or what configuration do y’all recommend?

6. Is there anything else we need to know about?

Regards,

Will

Sent from my iPhone

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [TUHS] Upgrading from 11/40 to 11/45 in Unix v6
@ 2018-12-31  6:51 Noel Chiappa
  2018-12-31 15:06 ` Will Senn
                   ` (2 more replies)
  0 siblings, 3 replies; 27+ messages in thread
From: Noel Chiappa @ 2018-12-31  6:51 UTC (permalink / raw)
  To: tuhs; +Cc: jnc

    > 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.

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [TUHS] Upgrading from 11/40 to 11/45 in Unix v6
@ 2018-12-31 17:20 Noel Chiappa
  0 siblings, 0 replies; 27+ messages in thread
From: Noel Chiappa @ 2018-12-31 17:20 UTC (permalink / raw)
  To: tuhs; +Cc: jnc

    > From: Will Senn

    > Thanks for not dismissing the thread as frivolity.

Hey, anyone wanting to do things with V6 I take seriously! :-)

    > I'm sure y'all have seen Mills's winning Best in Show IOCCC entry:
    > https://www.ioccc.org/2018/mills/hint.html

Yes, that was pretty awesome.


    > Fantastic, I'm prolly gonna try it.

OK; if you want to know what it's doing (somehow I figured you probably didn't
just want to simply follow the instructions :-) that is different from the /40
(it's quite different, and somewhat complicated), I just wrote this:

  http://gunkies.org/wiki/Unix_V6_kernel_memory_layout

to explain it a bit. Currently, one has to read the source to 'sysfix', and
also m45.s, to understand how the /45 version works; that new page is a little
crude still, but it hopefully explains the big picture.


    > If the instructions in Setting up are as good for the 45 as they are for
    > the 40, I should be able to bring one up relatively painlessly.

I just took a look at "Setting up UNIX - Sixth Edition", and it doesn't really
say much about the /45; it basically just says 'the /45 is wiered inside' and
'look at sys/run'. It is certainly true that that does cover all one needs to
bring V6 up on the /45, but... The coverage of what to do if your '45' has
hardware floating point is pretty complete, though.

    > What it sounds like is that Unix was transitioning from non-I/D land to
    > I/D land and maintaining a measure of backward compatibility

That's pretty accurate. One main advantage of the /45 is that it could have a
lot more disk buffers, but I'm not sure that makes much difference for
emulation. If you have some application that won't fit well in 64KB, that's
big, but that's a user-land difference, not the OS.


    > Is there a bootable tape of the MIT system extant?

Not yet, sorry. I do have a complete dump, but it i) includes all the users'
personal files, and ii) is not well organized. It's on my to-do list.

	 Noel

^ permalink raw reply	[flat|nested] 27+ messages in thread
* Re: [TUHS] Upgrading from 11/40 to 11/45 in Unix v6
@ 2018-12-31 18:38 Noel Chiappa
  2018-12-31 20:06 ` Warner Losh
  0 siblings, 1 reply; 27+ messages in thread
From: Noel Chiappa @ 2018-12-31 18:38 UTC (permalink / raw)
  To: tuhs; +Cc: jnc

    > From: Paul Winalski

    > What is magic number 0411?  That one I've never heard of before.

It's a PDP-11-ism. Separate I+D.

     Noel

^ permalink raw reply	[flat|nested] 27+ messages in thread

end of thread, other threads:[~2019-01-01  8:18 UTC | newest]

Thread overview: 27+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-12-31  2:25 [TUHS] Upgrading from 11/40 to 11/45 in Unix v6 Will Senn
2018-12-31  2:43 ` Clem cole
2018-12-31  3:31   ` Will Senn
2018-12-31 14:55     ` Clem Cole
2018-12-31 15:05       ` ron
2018-12-31 15:53         ` Clem Cole
2018-12-31 17:30           ` ron
2018-12-31 18:20             ` Paul Winalski
2018-12-31 23:36       ` [TUHS] Useful Unix tools + Usenix tapes Warren Toomey
2019-01-01  1:30         ` Clem cole
2019-01-01  1:58         ` Clem cole
2019-01-01  2:00           ` Clem cole
2019-01-01  2:08           ` Nigel Williams
2019-01-01  2:17             ` Warren Toomey
2019-01-01  8:18               ` Warren Toomey
2018-12-31  2:47 ` [TUHS] Upgrading from 11/40 to 11/45 in Unix v6 Clem cole
2018-12-31  3:08   ` Will Senn
2018-12-31  3:15     ` Clem cole
2018-12-31  6:51 Noel Chiappa
2018-12-31 15:06 ` Will Senn
2018-12-31 15:50 ` Clem Cole
2018-12-31 15:53   ` Warner Losh
2018-12-31 15:59     ` Clem Cole
2019-01-01  1:56 ` Eric Allman
2018-12-31 17:20 Noel Chiappa
2018-12-31 18:38 Noel Chiappa
2018-12-31 20:06 ` Warner Losh

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