Re: more on CD-ROM

[rwk@crl.dec.com]

In article <9201242021.AA24214@beta.lanl.gov> you write:
> Since the tide of the conversation has turned temporarily to CD-ROM...
> 
> Who else is using CD-ROM as a SYS host? What sort of problems have you
> had in combining the distribution software with layered products?

The CD-ROM is in an ISO standard format, which means it has a
standard filename syntax which is about as brain-damaged as
very early VMS filesystems.  (Long since improved).

Apparently, SUN's CD-ROM software includes an option for
lower-casing these filenames & converting the version number
syntax, replacing '_' with '-', etc.  This option doesn't
exist on other Unix systems, though, like Ultrix.

There are two solutions.  One, you (or Symbolics) could write the
appropriate set of logical-pathname translation rules.  (This is
NOT the SYS.TRANSLATIONS file but rather a set of rules which uses
SYS.TRANSLATIONS as data, and can run arbitrary code to perform the
translation).  I recommend that Symbolics do this in their next
possible release (it's probably too late for 8.2, I'd guess).

The other approach is to build a forest of links to the CD-ROM.
I have a perl script which does this, and it works quite well.
It has the added advantage that you can work with physical pathnames,
even from the Unix side.  It has the added cost of requiring space
for all those links (which is non-trivial but a lot less than the
CD-ROM), and it makes access just a little bit slower.

We don't really find the access speed a problem, however.
 
I can make my script available to anyone who needs it.

> For example, we found that Concordia tries to load several SAB files
> from SYS:DOC;ZMACS, which, unlike for the rest of the doc files, doesn't
> seem to translate properly. Trying to load individual SAB files from the
> CD throws to the debugger.

One problem is that a few of the filenames get truncated as a
result.  I'm told that in the release notes there's a list of
exceptions.  I'll be incorporating it into my forest-of-links
script when I get it.

> What is the "ideal" SYS.TRANSLATIONS file? We started by defaulting to
> the CD, and providing explicit translations for layered products, but
> it's hard to get all of the cases. We ended up doing the opposite,
> because at least the number of directories on the CD is bounded.

I'd say it depends on how many cases you have.  In our case,
the number of layered products is small and unlikely to grow.
We're likely to get new directories on the next CD-ROM, however.