Ultrix-11

[Peter Allan]

Thanks Warner and Ethan. That is very helpful.

I had not realised that the partition sizes were REALLY hard wired - as in
set in the code. That explains why there is no option to set the size at
installation time.

I will redo the installation with that in mind.

Cheers

Peter

On Fri, 20 Aug 2021 at 22:03, Warner Losh <imp at bsdimp.com> wrote:

>
>
> On Fri, Aug 20, 2021, 2:26 PM Peter Allan via cctalk <
> cctalk at classiccmp.org> wrote:
>
>> The idea of using an RA81 drive as it is bigger sounds like a simple
>> solution, but does it actually give a larger /usr partition? Even though
>> an
>> RD54 drive is not huge, most of it is not taken up by the root partition
>> plus the /usr partition, but is available for use as (on the video at
>> least) /user1.
>>
>> I will give it a try after the weekend and see what happens.
>>
>
> I was going to try tonight. The dksizes.c table suggests that it is 10MB
> instead of 8.5MB on the RD54. Yet someone else said it was smaller, so I
> wanted to check....
>
> Warner
>
>
> Cheers
>>
>> Peter Allan
>>
>> On Fri, 20 Aug 2021 at 17:38, Ethan Dicks <ethan.dicks at gmail.com> wrote:
>>
>> > On Fri, Aug 20, 2021 at 11:50 AM Peter Allan via cctalk
>> > <cctalk at classiccmp.org> wrote:
>> > > I just installed Ultrix-11 3.1 using the ultrix31.tap file from
>> > > https://pdp-11.org.ru/files.pl?lang=en
>> > > which is the location from the comments in Stephen's Machine Room
>> video
>> > on
>> > > YouTube that I think started this thread.
>> > >
>> > > It installed just fine, but just like the video, I ran out of space on
>> > /usr.
>> >
>> > /usr was usually tight back in the day.
>> >
>> > > How can I make a larger /usr partition? Is it possible to do this at
>> > > installation time? There did not seem to be an option for this. Can
>> it be
>> > > done by using an additional disk? That would seem likely, but not
>> what a
>> > > system manager back in the 70's or 80's would expect to need to do,
>> > > especially as there is a relatively large amount of space left to
>> create
>> > > /user1.
>> >
>> > In the 70s and early 80s, it was not at all uncommon to have multiple
>> > disk drives mounted to add up to enough space, especially to put user
>> > files on their own device to keep them from competing with free space
>> > in the system areas.  Also, older, smaller disks were often cheaper
>> > than the newest/largest disk drives, or systems would be put together
>> > from repurposed hardware rather than purchasing new.  For a single
>> > data point, my employer bought a new RA81 in 1984.  For 424MB it was
>> > $24,000.  Most machines had a _lot_ less disk in those days.  Our main
>> > UNIX machine was an old 11/750 (2MB RAM) with 2x RK07 (28MB each).  It
>> > was quite a jump when I put Ultrix 1.1 on an 11/730 w/RB80.  The CPU
>> > was 30% slower, but it had 5MB of RAM and a 121MB disk, so as a
>> > machine that spent most of its time with a single user (me), it was
>> > fine.
>> >
>> > When disks were routinely 1-30MB (RK05... RK07 or RP03), it was
>> > totally common to have 2-3 disks on a machine.
>> >
>> > All that said, I looked over this install write-up and it seems to
>> > assume you have one disk and it slices and dices with default sizes...
>> >
>> >
>> >
>> http://ftp.fibranet.cat/UnixArchive/Distributions/DEC/Fred-Ultrix3/setup-3.1.txt
>> >
>> > I've installed older versions of UNIX where you had to explicitly set
>> > up disks and partitions (where you _could_ resize partitions).  Prior
>> > to restoring the contents from tape.  That didn't appear to be as easy
>> > with this installer script.
>> >
>> > > I noted the options for installing software using soft links to other
>> > > locations. Was that the preferred method when installing additional
>> > > software?
>> >
>> > That was done, as was mounting an entire second disk for /usr.  One of
>> > the challenges is making sure you have enough tools accessible on the
>> > boot device to bring the machine up far enough to mount the additional
>> > devices.  This is part of why there are system tools in /bin,
>> > /usr/bin, etc.  You could depend on the contents of /bin being there
>> > before /usr was mounted.  Also, traditionally, programs in /bin were
>> > statically linked so that you didn't have to have specific libraries
>> > available at the time.
>> >
>> > The simplest solution, of course, is just get a bigger disk, but where
>> > that wasn't possible (which was most of the time), people did use soft
>> > links or multiple spindles to aggregate enough space to get by.
>> >
>> > Back in the day, I struggled to get enough disk space to install
>> > 2.9BSD on an 11/24.  Two RK07s would have been a luxury.  I had an
>> > RL02 (10MB) and I think maybe an RL01.  I could get the initial
>> > restore to work but I didn't have enough space to rebuild my kernel.
>> >
>> > -ethan
>> >
>>
>