BTW the time it was added (4.4), most of the tools did not use it.   Which was sad... and Ron points out.

On Sun, Sep 24, 2017 at 11:26 AM, Christian Barthel <> wrote:
ron minnich <> writes:

> [1:text/plain Hide]
> ptrace replaces procfs? Wow, that's a disappointing turn of events. It's
> also against the flow of thought in the Unix community I knew in 1980. If
> somebody has any of the old ca-1980 BSD manuals, you should find a BUGS
> section on ptrace advocating a move to a file-system-like interface. I
> always assumed ken wrote that little note when he was visiting UCB --
> anybody know?

I am also surprised to hear that ptrace replaces procfs.  In the 4.4BSD
Book[1] is a chapter about process debugging (chapter 4) with ptrace and
it says:

``The ptrace facility is inefficient for three reasons.  [...]''

And later, it mentions the proc filesystem:

``To address these problems, 4.4BSD added a /proc filesystem, similar to
the one found in UNIX Eight Edition [Killian, 1984]. [...]''

[1] The Design and Implementation of the 4.4BSD Operating System,
M.K. McKusic, Keith Bostic, Michael J Karels, and John Quarterman,
Addison-Wesley, Reading, 1996, ISBN 0-201-54979-4.

Kind regards,