Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!lll-winken!uunet!nuchat!steve
From: steve@nuchat.UUCP (Steve Nuchia)
Newsgroups: comp.unix.questions
Subject: Re: VMS: logicals  UNIX: links, but...
Message-ID: <6457@nuchat.UUCP>
Date: 15 Apr 89 15:19:40 GMT
References: <475@caldwr.UUCP> <810036@hpsemc.HP.COM>
Reply-To: steve@nuchat.UUCP (Steve Nuchia)
Organization: South Coast Computing Services, Inc.
Lines: 43

The analogy between "unix aliases" and VMS LOGICALS is not
at all accurate.  Unix has no aliases.  Certain Unix applications,
notably csh and ksh, have alias-like features.

There is already a perfectly useful and well-understood kernel
mechanism for associating a LOGICAL name with a PHYSICAL file --
links.  In fact there are two ways -- hard links and symbolic
links.  Your system doesn't have symbolic links?  Mine doesn't
either, but that's just because I'm too poor to get real Unix,
and even AT+T will have symlinks once Sun gets through giving
them SVR4.

The correct way to deal with billions of lines of JCL and associated
applications code is to implement compilers and/or interpreters, as
appropriate, for them.  It is the responsibility of the language
environment to implement the semantics of the language, and if that
semantics demands LOGICAL names then find a way to do it.  I'll eat
my V7 manual if you can point to an important (in terms of number of
applications that depend on it) feature that can't be implemented
on top of a merged BSD/SYSVR3 kernel.

For logicals specifically, set up some twinky little aliases
or commands to manipulate symbolic links residing in ~/.logicals
(or $HOME/.LOGICALS.DIR if you prefer).  If you can't require
symbolic links then you will also need a database of logical->physical
mappings to go with a directory full of hard links.

An even better way to access all that antique code is to find a
museum that will let you run an ethernet to their 370 and run it
in a window on your workstation.

Personal opinion mode, continued: the widely-held belief that
rewriting code is prohibitively expensive is a falacy.  It is
very dear to the hearts of management types, but it is bad economics.
The economic value in a software product resides in its crystalization
of the problem it solves, not in the billions of lines of FORTRAN
that it was implemented in, iteratively, back in the sixties and
that can't be changed now because no one understands it.  Code
that can't be maintained has *negative* value.
-- 
Steve Nuchia	      South Coast Computing Services
uunet!nuchat!steve    POB 890952  Houston, Texas  77289
(713) 964 2462	      Consultation & Systems, Support for PD Software.