[penguicon-general] A couple of thoughts about programming

[Robert Meier]

Rob,

> >        How GPS (Global Positioning System) works
> Eric would love to be on a GPS panel.
> >        How to get started geocaching
> Might interest some of the guests.
> > Relatively easy presentation topics include:
> >        java-linux
> "Why Java matters again"...

GPS, geocaching, java can be researched.



> POSIX became largely irrelevant to Linux because the spec isn't freely 
> available.  (You have to pay for it.)

I believe the above is unfortunately widely accepted FUD,
that misleadingly implies unavailability of practical interoperability in
the linux/unix community.



> >        POSIX (write once, run aix, hp-ux, linux, sunOS, SGI, ...)
You can read the lastest 2004 specification online with a free (i.e. 0.00 USD)
registration (only an email required)
    http://www.unix.org/single_unix_specification/
    http://www.unix-systems.org/version3/online.html 
or purchase on CD (or as a bookshelf of hardcopy)
for ~240 USD (less than the same size bookshelf of O'Reilly books).

You can purchase the 1991 specification on CD
    http://www.opengroup.org/bookstore/catalog/t912.htm
for 19.95 USD (less than Penguicon admission).

I personally have no objection to paying the IEEE, Open Group or O'Reilly
for their effort and publications.

> > It's been subsumed by SUSv3, which you can find at 
> > http://www.opengroup.org/onlinepubs/009695399/

<AFAIK>
SUSv3 is a publication of the IEEE 1003 and other standards required by POSIX.
SUSv3 does not subsume/replace POSIX anymore than "Learning Perl"
(the camel book) subsumes/replaces perl.
</AFAIK>

<IIRC>
~2hr research (http://www.uspto.gov/) will show that POSIX is a trademark
(1792095) like linux (1916230).  Commercial use of the POSIX trademark
indicates certified compliance with FIPS-189, IEEE Std 1003 (a.k.a.
ISO/IEC 9945), and several other standards.  Use of linux similarly
indicates compliant use of the kernel code tree.
Though commercial use of the POSIX trademark requires certified compliance,
       http://get.posixcertified.ieee.org/docs/posixfaq.html
writing and selling portable code (without using the POSIX trademark)
requires only compliance with IEEE Std 1003 (a.k.a. ISO/IEC 9945),
and any related standards if applicable.

The Open Group publishes the full POSIX spec, including IEEE Std 1003,
and other standards as the Single Unix Specification, analagous to the
as yet unreached target of the linux documentation project.
</IIRC>



> >        rpm spec (wrapping tarballs with dependencies, and pushbutton build)
> rpm is cpio based, deb is the one that's tar based.
> (I believe ipkg, portage, and slackware are also tar based).

A source rpm is a cpio file which includes
  o original unaltered package files (tarball, .zip, ...)
  o patch files to copy-and-alter the original package files
  o .spec file, macro processor input to produce shell scripts

In typical unix do-things-reversibly fashion,
a package developed as a tarball(, .zip, ...), can be wrapped as a source rpm,
and a source rpm can yield the original tarball(, .zip, ...).

In typical unix textual fashion (like apache config files),
the .spec file, is human readable,
yet computer-automated description of build, test, relocate details.

> I've personally found rpm to be increasingly irrelevant ...  Ubuntu 
> and Knoppix are both .deb based, and the only other system I play with much 
> (gentoo) has its own (portage).


While RedHat, SuSE, and even AIX users abound, rpms will remain useful.
Similar research and presentation on how to wrap simple tarballs for 
deb and portage should also be useful.

There are large archives of rpm packages (e.g. http://www.rpmfind.org/)
which become available to deb or portage users who understand rpms,
especially as rpm(8) can be used simultaneously on distros based on
other package managers.

rpm supports (but does not enforce by default) installations that are
completely reversible (even when installation fails), as well as testing
before installation, non-root installation, and (if supported by the
underlying package) completely relocatable installation.

As distros and package managers evolve, I believe many linux users
would want to learn the features (and failings) of several package managers
so the user can choose what's best for the user, without archive and distro
package manager restrictions.

Reporting,
-- 
Dr. Robert J. Meier

Warble, warble, little sat,
How I wonder where I'm at.
Twice around the world each day,
Four and twenty birds at play.
     -- extract from "Ode to NavStar IIa" 2001 Dr. Robert Meier