From owner-freebsd-hackers  Fri Jul 28 19:13:28 1995
Return-Path: hackers-owner
Received: (from majordom@localhost)
          by freefall.cdrom.com (8.6.11/8.6.6) id TAA18447
          for hackers-outgoing; Fri, 28 Jul 1995 19:13:28 -0700
Received: from UUCP-GW.CC.UH.EDU (UUCP-GW.CC.UH.EDU [129.7.1.11])
          by freefall.cdrom.com (8.6.11/8.6.6) with SMTP id TAA18428
          for <hackers@freebsd.org>; Fri, 28 Jul 1995 19:13:24 -0700
Received: from Taronga.COM by UUCP-GW.CC.UH.EDU with UUCP id AA14232
  (5.67a/IDA-1.5); Fri, 28 Jul 1995 20:47:44 -0500
Received: by bonkers.taronga.com (smail2.5p) id AA13326; 28 Jul 95 20:19:27 CDT (Fri)
Received: (from peter@localhost) by bonkers.taronga.com (8.6.11/8.6.6) id UAA13323; Fri, 28 Jul 1995 20:19:26 -0500
From: Peter da Silva <peter@bonkers.taronga.com>
Message-Id: <199507290119.UAA13323@bonkers.taronga.com>
Subject: Re: your mail
To: jkh@time.cdrom.com (Jordan K. Hubbard)
Date: Fri, 28 Jul 1995 20:19:25 -0500 (CDT)
Cc: hackers@freebsd.org
In-Reply-To: <8635.806962669@time.cdrom.com> from "Jordan K. Hubbard" at Jul 28, 95 01:17:49 pm
X-Mailer: ELM [version 2.4 PL23]
Content-Type: text
Content-Length: 1348      
Sender: hackers-owner@freebsd.org
Precedence: bulk

> > > > I disagree. Oh, not in the user interface model, but in the file system
> > > > and process model. It takes the UNIX "everything is a file" a logical
> > > > evolutionary step forward.

> > > Oh great.  One of UNIX's worst abortions, taken to extremes (can you
> > > say "ioctl() is a bogus ``API'' for controlling behavior?"  I thought
> > > so)..

> > Plan 9 doesn't have IOCTL at all. Just about everything is done with open,
> > close, read, and write.

> So how do you do "out of band" operations, like telling a tape
> drive to skip forward to the next mark?

The tape has a "data" and a "control" device. You write commands to the
control device.

You can read all the Plan 9 papers at plan9.att.com, and there's a lot of
very interesting stuff in there. For example, mounts are local to the
process, like current directory and environment variables are for UNIX.
So when a program is running under 8 1/2 it has a set of devices for the
screen and mouse visible. When you run 8 1/2, it opens the *same* devices,
so you can run 8 1/2 in a 8 1/2 window...

One of the devices is /dev/bitblt.

Backups are handled the same way, and you can do things like:

find 1995/07*/sys/src/cmd -name '*.c' | xargs grep -i bug

If you want to work on the system as it was in July 1995, you do:

	bind("1995/0701/sys/src", "/sys/src", REPLACE)

...