The feel of a LispM/List of running machines

[Luca Pisati]

Alaric B. Williams wrote:
> 
> On  1 May 97 at 13:28, Mike McDonald wrote:
> 
> > To:            alaric@abwillms.demon.co.uk
> > Cc:            lispos@math.gatech.edu
> > Subject:       Re: The feel of a LispM/List of running machines
> > Date:          Thu, 01 May 1997 13:28:13 -0700
> > From:          Mike McDonald <mikemac@titian.engr.sgi.com>
> 
> > >From: "Alaric B. Williams" <alaric@abwillms.demon.co.uk>
> > >To: Martin Cracauer <cracauer@cons.org>
> > >Date: Thu, 1 May 1997 20:24:48 +0000
> > >Subject: Re: The feel of a LispM/List of running machines
> 
> Hey, same mailer :-)
> 
> > >I'd be most interested to know how the LispM dealt with:
> > >
> > > - Storage. Files? Persistent objects? A directory structure?
> 
> >   LispMs had a hierarchical file system. Pathnames looked like
> > titan:>mac>graphics>painter.lisp.37.
> 
> So the bit before the colon selects a network machine, like
> a URL? That's pretty handy.

BTW: ANSI-CL pathname structure is modeled on the LispM concept.

An example from our application:

USER(1): #p"ngc:patch;nworld-3-1;nworld-3-1-001.fasl"
#p"ngc:patch;nworld-3-1;nworld-3-1-001.fasl"

USER(2): (describe *)
#p"ngc:patch;nworld-3-1;nworld-3-1-001.fasl" is a structure of type LOGICAL-PATHNAME.  It has these slots:
 HOST               "ngc"
 DEVICE             :UNSPECIFIC
 DIRECTORY          (:ABSOLUTE "patch" "nworld-3-1")
 NAME               "nworld-3-1-001"
 TYPE               "fasl"
 VERSION            :UNSPECIFIC
 NAMESTRING         NIL
 HASH               64954

USER(3): (translate-logical-pathname **)
#p"/TREES/devo/nworld-3-1/patch/nworld-3-1/nworld-3-1-001.fasl"

USER(4): (describe *)
#p"/TREES/devo/nworld-3-1/patch/nworld-3-1/nworld-3-1-001.fasl" is a structure of type PATHNAME.  It has these slots:
 HOST               :UNSPECIFIC
 DEVICE             :UNSPECIFIC
 DIRECTORY          (:ABSOLUTE "TREES" "devo" "nworld-3-1" "patch" "nworld-3-1")
 NAME               "nworld-3-1-001"
 TYPE               "fasl"
 VERSION            :UNSPECIFIC
 NAMESTRING         NIL
 HASH               NIL

Notice as the HOST slot is :UNSPECIFIC in Unix (as well as the VERSION slot)

> > They also supported logical
> > pathnames like sys:color;alu.lisp. A logical pathname would get
> > converted into a physical pathname by the system using info stored in
> > sys.translation files. Physical pathnames were of the form host:<host
> > specific path>. For instance, trantor:/usr/mac/foo.lisp was also a
> > vaild physical pathname, that happens to refer to a file on a Unix
> > host.
> 
> So it could transparently use different protocols to access hosts?
> Yet again, pretty handy!

Standard ANSI-CL features.

> >   Printers didn't live in a "printer's directory". They were
> > represented by namespace object, along with hosts, users, and sites.
> > Theyre were commands to print files and do screen dumps (anyone else
> > hack LPGs?). Since this was before the days of PostScript, if you had
> > a PS printer hooked up and wanted to generate specific PS for it,
> > you'd have to do that yourself. (You could print text and do screen
> > dump to it, though.)
> 
> That seems pretty good, although obviously the ability to speak to
> printers in a high level graphics language instead of characters would
> be nice - a character stream smells of UNIX :-)
> 
> >   Mike McDonald
> >   mikemac@engr.sgi.com
> 
> Thanks,
> 
> ABW
> --
> Alaric B. Williams (alaric@abwillms.demon.co.uk)
> 
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--
Luca Pisati		       Voice:	 (310) 577-0518
Nichimen Graphics	       Fax:	 (310) 577-0577
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