Re: 32-bit pid_t / security

[Keith Owens]

On Mon, 2 Oct 2000 11:27:16 +0100 (BST), 
Alan Cox <[e-mail]> wrote:
>S/390 folks run 70,000 sessions active within the same 60 second period off
>one big box. Not on Linux (yet ;)) but its worth bearing in mind.

FYI, OS/390 Unix System Services uses a halfword for the maximum number
of processes in system limits MAXPROCSYS and MAXPROCUSER.  The fields
are defined as full words but the API only uses the low half word.
Even their pid is structured as (big endian)

  Bit 0           Reserved, must be 0
  Bit 1-7         Slot reuse counter.
  Bit 8-15        Reserved, currently 0.
  Bit 16-31       Process slot number.

Obviously IBM think that 64K concurrent processes is enough for anyone,
even on big iron.  Now where have I heard that before ;)?