Article View: comp.sys.amiga.tech
Article #6297Re: PIPEs
From: Pete Goodeve
Date: Fri, 02 Nov 1990 21:19
Date: Fri, 02 Nov 1990 21:19
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In <1990Nov2.173103.18889@engin.umich.edu>,
Ralph Seguin (gilgalad@caen.engin.umich.edu) wrote:
>
> The major problem with any of the pipe implementations for the Amiga is
> that they build "named" temporary files. Kinda bad, when you're trying
> to use pipes as an IPC with files larger than a megabyte. For instance:
>
> ilbmtoppm blah.iff|ppmquant 256|ppmscale -yscale 1.4|ppmtogif >blah.gif
>
> Hmmm... Let's see, that's 3 megs worth of temp files.
>
Now exactly WHERE did you get THAT idea??! There is no pipe on the Amiga
that I know of that works this way. (On the IBM on the other hand...!)
Both the 1.3 (Matt Dillon) pipes and Ed Puckett's directory-based version
use circular buffers of fixed size: if the buffer gets full, the writer
will block until the reader takes some out of it. No disk storage at
all is used!
My IP-Device works a little differently in that the packet passed by the
writer acts as a temporary buffer until it is read, which minimizes byte
copying (but may cause the writer to block more readily).
-- Pete --
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!agate!violet.berkeley.edu!pete From: pete@violet.berkeley.edu (Pete Goodeve) Newsgroups: comp.sys.amiga.tech Subject: Re: PIPEs Summary: No Way..! Keywords: PIPE, IP-Device Message-ID: <1990Nov2.211906.6904@agate.berkeley.edu> Date: 2 Nov 90 21:19:06 GMT References: <1990Oct19.044319.4851@engin.umich.edu> <1990Nov2.091542.25505@agate.berkeley.edu> <1990Nov2.173103.18889@engin.umich.edu> Sender: usenet@agate.berkeley.edu (USENET Administrator) Distribution: na Organization: University of California, Berkeley Lines: 24