[Python-ideas] BetterWalk, a better and faster os.walk() for Python

[Andrew Barnert]

From: Steven D'Aprano <steve at pearwood.info>
Sent: Thu, November 22, 2012 8:52:56 PM


> 
> On 23/11/12 13:48, Andrew Barnert wrote:
> >> From: Robert Collins<robertc at robertcollins.net>
> >>  Sent: Thu, November 22, 2012 4:26:49 PM
> >>
> >> If you want to  test cold cache behaviour, see   /proc/sys/vm/drop_caches
> >>
> >> -Rob
> >
> >
> > On  a Mac? There's no /proc filesystem on OS X; that's linux-specific.
> 
> I  don't think that is correct. /proc is a UNIX feature, not just Linux. 

To make it more clear:

The existence of /proc is a non-standardized feature that some, but not, all 
UNIXes have—OS X is one of those that does not.

Almost all UNIX and UNIX-like systems that do have /proc have a directory per 
process, with read-only binary information about those processes, and nothing 
else.

The idea of writing to magic text files under /proc/sys to control the OS is 
entirely specific to linux.

See https://blogs.oracle.com/eschrock/entry/the_power_of_proc for the Solaris 
perspective, 
and http://lists.freebsd.org/pipermail/freebsd-fs/2011-February/010760.html for 
the FreeBSD perspective, to get an idea of how unique linux /proc is, and why 
it's likely to stay that way.

> OS X is also a Unix. Since 10.5, OS X has been registered with the  SUS
> ("Single UNIX Specification") and has received UNIX  certification.

Yes, and SUS/POSIX/OpenGroup doesn't specify /proc/sys, or even basic /proc, or 
epoll or /dev/cdrom or GNOME or half the other things you have on your Linux 
box. OS X is a UNIX system, not a Linux system.