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The Unix Time-Sharing System (1974) [pdf] (berkeley.edu)
92 points by alexis-d on Mar 22, 2016 | hide | past | web | favorite | 17 comments

Gotta love this gem: "Perhaps the most important achievement of UNIX is to demonstrate that a powerful operating system for interactive use need not be expensive either in equipment or in human effort: UNIX can run on hardware costing as little as $40,000..."

Still rings true for Mac.

And IBM's AIX. :)

You meant OS X? ;-)

Note that according to BLS's CPI, that's $192,000 in 2016 dollars.

Still, it was an amazing achievement for nonetheless relatively affordable PDP-11/45, on which it was eminently usable, and in many ways better than anything else out there aside from it's Multics forefather.

(Originally ran on a first generation PDP-11, later the 11/20, with an extra memory unit so it could run split Instruction and Data (I&D) and have decent budgets for both; on the 11/45, that would be up to 64KiB code, 56KiB data, and 8KiB stack.)

It's kind of a bloated memory hog. It takes up 42kB.

It's kind of funny to consider that modern desktop and server CPUs can have more Level-1 cache than that.

And they ran that system on a machine with 144kB of RAM, where desktop CPUs have had more Level-2 cache than that for years now.

And by now, as somebody else kindly points out, high end server CPUs approach Level 3 caches as big as the hard drive their system ran on... (I think zSeries CPUs have level 3 or level 4 caches in the 128MB range, so their caches actually are bigger than that.)

> We will not attempt any interpretation of these figures nor any comparison with other systems, but merely note that we are generally satisfied with the overall performance of the system.

Will write that in one of my upcoming research papers and see how it turns out.

See also this earlier document (1971) posted on HN a few months ago: https://news.ycombinator.com/item?id=10660727

Filenames were limited to 14 characters!

A lot better than MS-DOS's 8.3!

14 bytes for filename, and as I recall 2 for the inode in that particular filesystem, so a total of 16 bytes per directory entry. I'm not sure what the typical minimal disk space budget was, but assume as little as 5 MiB, e.g. 2 RK05s, so you had to make every byte count. On a student run computer center I started with the Logo Lab's surplus PDP-11/45, we considered ourselves very lucky to have scored the prototype CONS Lisp Machine's CDC SMD 80 MiB (unformatted) drive to run the system on. Note that the latest Haswell Xeon CPUs are getting up to a max of 45 MiB L3 cache....

What was much worse was that many programs just opened directories as files (which of course they are) and assumed that format, which caused more than a little pain when we moved to bigger machines and more sophisticated filesystems.

Usernames are still limited to 8 characters in HP-UX as far as I know.

Until about ten years ago there was also an 8 character limit on Solaris, but for passwords.

That was probably the one thing I hated the most in Solaris. We would have various platforms linked up together via NIS, which was synced against our Windows 2000 domain controller (I know, sounds horrible. But it did work surprisingly well in its day). For all the jokes about Windows security, even that supported longer passwords. And users did occasionally notice when logging into Solaris eg when they accidentally typoed as they hit enter. All I could say was "yes, I know it seems dumb. It's Solaris and we can't do much about that."

Mmh look at that max uptime: two weeks -a whole 98% - A crash every other day ! Fortunately things evolved to winME stability since then (I know no multiuser)


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