1 Aug
2019
1 Aug
'19
11:43 p.m.
From: Dave Horsfall
it actually *unlinked* directories
Maybe the application was written by a LISP programmer? :-)
(Not really, of course; it was probably just someone who didn't know much
about Unix. They had a list of system calls, and 'unlink' probably said '
only
works on directories when the caller is root', so...)
Speaking of LISP and GC, it's impressive how GC is not really a big issue any
more. At one point people were even building special CPUs that had hardware
support for GC; now it seems to be a 'solved problem' on ordinary CPUs.
Noel
2 Aug
2 Aug
1:03 a.m.
New subject: Who's behind the UNIX filesystem permission
On 2 Aug 2019, at 09:43, Noel Chiappa <jnc(a)mercury.lcs.mit.edu> wrote:
Speaking of LISP and GC, it's impressive how GC
is not really a big issue any
more. At one point people were even building special CPUs that had hardware
support for GC; now it seems to be a 'solved problem' on ordinary CPUs.
I think it’s mostly a side effect of modern hardware speeds. For applications that care
about latency (and especially latency jitter) it’s still an issue.
For example, writing low latency trading software in Java requires some fairly silly
hoop-jumping to avoid triggering a collection pass.
These apps genuinely care about nanoseconds, but the tooling ecosystem and development
time advantages of Java seem to entice a decent number of people to embark on the
work-arounds.
In most areas though you’re absolutely right — it’s a non-issue now.
d
4:36 a.m.
New subject: Who's behind the UNIX filesystem permission
In Go we "just" dedicate a core to GC, problem solved. The arrival of
universal multi-CPU hardware made than option. Some tremendous technical
work required (for which I take zero credit; see
https://blog.golang.org/ismmkeynote) but yeah.
-rob
On Fri, Aug 2, 2019 at 11:11 AM David Arnold <davida(a)pobox.com> wrote:
On 2 Aug 2019, at 09:43, Noel Chiappa
<jnc(a)mercury.lcs.mit.edu> wrote:
Speaking of LISP and GC, it's impressive how
GC is not really a big
issue any
more. At one point people were even building
special CPUs that had
hardware
support for GC; now it seems to be a 'solved
problem' on ordinary CPUs.
I think it’s mostly a side effect of modern hardware speeds. For
applications that care about latency (and especially latency jitter) it’s
still an issue.
For example, writing low latency trading software in Java requires some
fairly silly hoop-jumping to avoid triggering a collection pass.
These apps genuinely care about nanoseconds, but the tooling ecosystem and
development time advantages of Java seem to entice a decent number of
people to embark on the work-arounds.
In most areas though you’re absolutely right — it’s a non-issue now.
d
7 Aug
7 Aug
2:35 a.m.
New subject: Who's behind the UNIX filesystem permission
On Thu, 1 Aug 2019, Noel Chiappa wrote:
Maybe the application was written by a LISP
programmer? :-)
(Not really, of course; it was probably just someone who didn't know much
about Unix. They had a list of system calls, and 'unlink' probably said '
only
works on directories when the caller is root', so...)
I dimly recall that there was a little-documented utility /etc/unlink
which did just that; it was probably not on all systems, but was on our
CCI Power 6/32.
I only discovered their incompetence at the next reboot, when I had to
clean up all the orphaned (but temporary) files that were left behind
because [idn]check went berserk (we didn't have fsck back then).
-- Dave
1816
days inactive
1822
days old
3 comments
4 participants
participants (4)
-
Dave Horsfall -
David Arnold -
jnc＠mercury.lcs.mit.edu -
Rob Pike