Re: Are We Back to the "Wars" Now ?

On Sun, 24 Nov 2024 14:25:10 +0000, Rich wrote:

186282@ud0s4.net <186283@ud0s4.net> wrote:

On 11/23/24 4:25 PM, Lawrence D'Oliveiro wrote:

That’s irrelevant.  Pipes originated on the earliest Unix machine,
which was a PDP-11 with only a 64kiB address space.  They work great
for pumping around gigabytes of data, but you don’t need
gigabyte-sized memory buffers to do that.

 
  It all has to be SOMEWHERE ... if not in RAM then
  on a mass storage device.

 
Nope, at least not with pipes.

Hold on a sec.... pipes are /buffered/ in RAM, so there's at least
a small bit of ram set aside for each open pipe. On Linux, pipe(7)
says "In Linux versions before 2.6.11, the capacity of a pipe was
      the same as the system page size (e.g., 4096 bytes on i386).
      Since  Linux  2.6.11, the pipe capacity is 65536 bytes. Since
      Linux 2.6.35, the default pipe capacity is 65536 bytes, but
      the capacity can be queried and set  using the  fcntl(2)
      F_GETPIPE_SZ  and F_SETPIPE_SZ operations.  See fcntl(2) for
      more information."
and that "capacity" referred to consists of a kernel-managed RAM buffer.

[snip]



--
Lew Pitcher
"In Skills We Trust"