[tlb]

RTM, PG and I used BSDI (a commercial distribution of 4.4BSD) at Viaweb (starting 1995) and migrated to FreeBSD when that became stable. RTM and I had hacked on BSD networking code in grad school, and it was far ahead of Linux at the time for handling heavy network activity and RAID disks. PG kept using FreeBSD for some early web experiments, and then YC's website, and then for HN.

FreeBSD is still an excellent choice for servers. You may prefer Linux for servers if you're more familiar with it from using it on your laptop. But you use Mac laptops, FreeBSD sysadmin will seem at least as comfortable as Linux.

[caslon]

Do you think this influenced early YC companies more generally? For example, reddit's choice in picking FreeBSD over Linux?

It's interesting that they might still be on Lisp if they hadn't picked FreeBSD (a chiefly cited concern was that spez's local dev environment couldn't actually run reddit, which seems like it wouldn't have been a problem with Linux, since Linux & OS X both had OpenMCL (now known as CCL) as a choice for threaded Lisp implementations at the time).

[tlb]

Lisp was indeed a hassle on FreeBSD. Viaweb used CLisp, which did clever things with the VM system and garbage collection that weren't quite portable (and CLisp's C code was all written in German for extra debugging fahrvergnügen.)

I don't know how Reddit came to use FreeBSD, but if you asked which OS to use around university CS departments in 2005 you'd get that answer pretty often.

[caslon]

Yeah, absolutely; wasn't criticizing the choice of FreeBSD more generally (short of elegant maybe, but the only real UNIX systems available these days are illumos and xv6, and they're short of elegant, too), just thought it odd for that specific use case.

Thanks for answering! That's really interesting about clisp; I've always found it a more comfortable interactive environment than any other Common Lisp, but it definitely sacrifices portability for comfort in more ways than one (lots of symbols out of the box that aren't in the HyperSpec or any other implementation, too, for example). I'm now really thankful I've never been tempted to look to its source!

[skissane]

> the only real UNIX systems available these days are illumos and xv6

I do wonder how you are defining "real UNIX system" in that statement.

[caslon]

How do you define UNIX? Don't use "a system licensed to use the trademark," as that's boring and includes many things that are definitely far from it. It's hard to pin down! I'd say it's easiest to define what isn't: massive systems.

Massive systems miss the design intent and, to a great extent, nearly every benefit of using UNIX over VAX.

This excludes many of the operating systems licensed to use the trademark "UNIX." In this regard, even though Plan 9 is obviously not UNIX, it's a lot closer to it than (any) Linux and FreeBSD.

[skissane]

> Massive systems miss the design intent and, to a great extent, nearly every benefit of using UNIX over VAX

I take it you meant to say "VMS" here, not VAX.

I don't think the size of a system is essential to whether it counts as "UNIX" or not. The normal trajectory of any system which starts small is to progressively grow bigger, as demands and use cases and person-years invested all accumulate. UNIX has followed exactly that trajectory. I don't see why if a small system gradually grows bigger it at some point stops being itself.

I think there are three main senses of UNIX – "trademark UNIX" (passing the conformance test suite and licensing the trademark from the Open Group), "heritage/genealogical UNIX" (being descended from the original Bell Labs Unix code base), "Unix-like" (systems like Linux which don't descend from Bell Labs code and, with rare exception, don't formally pass the test suite and license the trademark, but which still aim at a very high degree of Unix compatibility). I think all three senses are valid, and I don't think size or scale is an essential component of any of them.

UNIX began life on small machines (PDP-7 then PDP-11), but was before long ported to some very large ones (for their day) – such as IBM mainframes – and the operating system tends to grow to match the scale of the environment it is running in. AT&T's early 1980s IBM mainframe port [0] was noticeably complicated, being written as a layer on top of the pre-existing (and obscure) IBM mainframe operating system TSS/370. If being small is essential to being UNIX, UNIX was only a little more than 10 years old before it was already starting to grow out of being itself.

[0] https://www.bell-labs.com/usr/dmr/www/otherports/ibm.pdf