Ultrix-11

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

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

> done by using an additional disk? That would seem likely, but not

> 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

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...

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. 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