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

"186282@ud0s4.net" <186283@ud0s4.net> writes:

On 11/24/24 2:14 PM, Richard Kettlewell wrote:

Lew Pitcher <lew.pitcher@digitalfreehold.ca> writes:

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.

>
The word ‘all’ isn’t just decoration.  The claim was ‘it all has to
be somewhere’, and Rich’s point (as I understand it) is that it does
not all have to be somewhere.
>
For example,
   head -c $((1024*1024*1024)) /dev/urandom | sha256sum
puts a gigabyte of data through a pipe, but at no point does anything
allocate anywhere close to a gigabyte of storage of any kind.

>
  There's truth here ... the gigabyte gets kinda 'spread out'.
>
  But what if it was ten GB, or 100 ?

What difference do you think it’ll make? It’ll take proportionately
longer, but that’s all.


(SHA256 maxes out at a couple of exabytes, but that’s nothing to do with
pipes. Replace with a SHA3 variant if you want to think about sizes
beyond that.)

  So, if you wanna count on sending vast quantities of
  data in pipes, go ahead - it'll almost always work.

When do you think it will stop working?

--
https://www.greenend.org.uk/rjk/