Path: ...!eternal-september.org!feeder2.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail From: Rich Newsgroups: comp.os.linux.misc Subject: Re: Are We Back to the "Wars" Now ? Date: Sun, 24 Nov 2024 19:36:57 -0000 (UTC) Organization: A noiseless patient Spider Lines: 30 Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Injection-Date: Sun, 24 Nov 2024 20:36:57 +0100 (CET) Injection-Info: dont-email.me; posting-host="f9f41132f628b1fe2d858245900693aa"; logging-data="2494652"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1/QHuzMUiYSmfVbq20RxNSV" User-Agent: tin/2.6.1-20211226 ("Convalmore") (Linux/5.15.139 (x86_64)) Cancel-Lock: sha1:7NlJH/RikqAtc7hBoyfCgR+E+hE= Bytes: 2603 Richard Kettlewell wrote: > Lew Pitcher 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. Exactly.