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 <[email protected]> wrote: > > > On Fri, Aug 20, 2021, 2:26 PM Peter Allan via cctalk < > [email protected]> 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 <[email protected]> wrote: >> >> > On Fri, Aug 20, 2021 at 11:50 AM Peter Allan via cctalk >> > <[email protected]> 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 >> > >> >
