[TUHS] Ancient Unixes

[imp@bsdimp.com (Warner Losh)]

From: "Bill Cunningham" <billcu1@verizon.net>
Subject: [TUHS] Ancient Unixes
Date: Mon, 24 Apr 2006 16:28:08 -0400

>     I am copying all I can from the unix archive and will burn it to cd
> because I know how precious they are. But what I was thinking was v5,6,7 for
> example. Take them and add USB support. Linux would be a good example from
> which to draw from. Because it's Posix. Much more could be adde to /dev.

Linux is very unlike early v[567] kernels.  Those kernels are not
posix by any stretch of the imagination.  In addition, Posix is a
userland interface, not an internal kernel structure, so even if they
were posix, I'm not sure how much it  would help you.  Porting Linux's
usb stack to FreeBSD, say, would be really hard because Linux and
FreeBSD have such different intenral kernel APIs.

You'll also run into the size issue if you want to implement a generic
stack.  For example, FreeBSD's usb stack is 100kB.  While one could
slim that down a lot (it include multiple drivers and such), it would
be difficult to fit in the space contraints of the PDP-11  It should
be possible, but one's first naive attemept to implement things may
not be so straight forward.

Warner