Re: [9fans] So What is P9 good for.....

[Geoff Collyer <geoff@collyer.net>]

Yes, one can cite individual complaints about 6th edition, but my
point was that in 1975 or 1976, compared to the other systems of the
day, Unix *seemed* *to me*, as a user, virtually free of arbitrary
limits.

I could create directories beneath my home directory to a depth
greater than 6 (unlike, say, TOPS-10 and perhaps, later, VMS), indeed
to arbitrary depth (yes, I'd run the file system out of blocks or
i-nodes eventually, but at least the system didn't pick a
pseudo-random constant like `6').  I could create files with names
that weren't 6+3 upper-case alphanumerics, unlike most, if not all,
DEC operating systems and others influenced by them.  14 (ASCII)
characters per component seemed most generous and I can't recall
needing more.  The exec argument limit was an implementation artifact
of a small machine, and has been increased repeatedly over the years,
unlike the limits mentioned above, which couldn't be changed without
harming binary compatibility with existing programs.  8-bit userids
were a result of parsimonious choice of the `char' data type on a
small machine, not somebody saying `Let's limit the number of users to
169 just to be arbitrary and a pain', and the size of userids has been
increased over the years.

Reading through section II of the 6th edition manual (the system call
interface), about the only arbitrary limits (perhaps I should say
capricious; those that are not just a consequence of the size of some
data type) that I can see are the maximum number of open files per
process and, arguably, various output delays in STTY(II).  This was
not true of the system call interfaces of most other systems of the
day (not to mention programming language implementations), where it
was normal to find a general mechanism described, followed by a
limitation to some capricious number, usually small enough to
seriously limit the utility of the mechanism, and often further
reducible by the system administrator during system configuration, so
you couldn't even count on the miserly nominal limit in the
documentation.  Quoting Armando Stettner of DEC (from memory), ``Unix
isn't a police-state operating system.''.

And (returning to the question of why I use Plan 9) the feeling I got
reading the CACM Unix paper appeared again when reading about Plan 9
circa 1991.