From: Tim Shoppa <shoppa@alph02.triumf.ca>
Message-Id: <9712051653.AA01585@alph02.triumf.ca>
Subject: PDP-11: Disk over Serial proposal (fwd)
To: pups@minnie.cs.adfa.oz.au
Date: Fri, 5 Dec 1997 08:53:53 -0800 (PST)
Content-Type: text
Sender: owner-pups@minnie.cs.adfa.oz.au
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> Ok, it would be nice to have a way of installing Unix onto a PDP-11 without a
> tape drive. Here's a proposal: please comment on it (i.e shoot it down!). I
> actually wrote a very similar system to move files off my Apple ][ once.
> 
> The PDP-11 is connected serially to another computer, using a DL11 port. The
> other computer will simulate one or more disk drives which are acessible by
> commands sent over the serial line.
> [Protocol description]
> Do we need a more sophisticated protocol with checksums, multiple outstanding
> commands, acknowledgments, framing bytes etc.?

Your proposal sounds very similar to the existing protocol (RSP) used
to access remote block-addressable devices (TU58's) over a DL11 port.
Why not just choose the RSP protocol?  It has the advantages of already
being defined and it already has support in most DEC OS's.  It could
be easily extended to support larger devices.  And RSP-servers
already exist for BSD-ish systems - see, for example, 

ftp://sunsite.unc.edu/pub/academic/computer-science/history/pdp-11/utils/tu58

Tim. (shoppa@triumf.ca)