Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!utgpu!water!watmath!clyde!cbosgd!ihnp4!ptsfa!ames!ucbcad!ucbvax!INGRES.BERKELEY.EDU!hatcher
From: hatcher@INGRES.BERKELEY.EDU.UUCP
Newsgroups: comp.sys.amiga
Subject: Re: MCC pipes
Message-ID: <8706120738.AA09510@ingres.Berkeley.EDU>
Date: Fri, 12-Jun-87 03:38:49 EDT
Article-I.D.: ingres.8706120738.AA09510
Posted: Fri Jun 12 03:38:49 1987
Date-Received: Sun, 14-Jun-87 01:48:14 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Lines: 39

Both Peter & Matt's comments about pipes were quite interesting.
Unfortunately Matt neglected to answer Peter's comment about wanting
pipes to support Examine and Exnext.

This is a very important feature. The ideal, which tends to be discovered
and rediscovered endlessly, is to have a consistent name space where
everything is a first class citizen. The reason is simple...when things
are very consistent, then software tends to work automatically with
objects that the author didn't have in mind a priori.

The Amiga currently has *almost* consistent universal name space,
as illustrated by the fact that Matt can write a pipe: device in
the first place, and any software can write to it as if it were
a regular file.

But unlike other devices which contain file names, the pipe: device
cannot be listed (Examine/Exnext etc). If it supported those packet
types then it would behave a lot more like our other devices. A
practical example: I have sometimes used more than one pipe at
once (good old multitasking Amiga!), and after scrolling several CLI's
and swapping windows around, wanted to check what was going on with
the pipes. The ideal way would be to do "dir pipe:". A second problem
was that I had gotten a writer going to a pipe, then it took a while
to set up the reader, but I couldn't remember the name I'd used for
the pipe (and the command had scrolled off the top of the CLI window).
Again, being able to do "dir pipe:" would fix that.

These are just a few examples; consistency and universality of interfaces
are well established principles by now. There are many discussions of
these principles in histories of Unix and Smalltalk, to pick two easy
examples. One ignores history at ones own peril (and to the inconvenience
of clients of your software).

Oh, a final note: it's nice to have a root in which to look at a name
space. That's why devices on Unix live in the file system in /dev
-- it's not a peculiarity, it's a very basic feature of a uniform
name space. It would be very nice if we could do "dir ::" or something
and discover a list of all devices.
	Doug Merritt		ucbvax!unisoft!certes!doug