Mailinglist Archive: opensuse (1231 mails)

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Re: [opensuse] own environment variables in init scripts
Cristian Rodríguez said the following on 03/05/2013 09:29 AM:
El 05/03/13 05:40, Meike Stone escribió:

Yes, I know systemd ... I'm not enjoyed about that on servers ... it
is in my opinion against the KISS principle. I does not care for the
time of boot process.
I'm looking forward, what SuSE is going to do with systemd in SLES12
,,, In case of Desktops, it makes really sense.

Looks like you need to read.. :)

+1 on all counts!

I'm really enjoying working with systemd, its properly worked out unlike
the ad-hoc-ism or systemvscripts! It really does embody the KISS
principle - modularization within a well specified framework, clear
command and communication methods, small and clear modules, elimination
of many of the coupling problems (not least of all environment
settings!) of systemvscripts.

There are a few basic principles of good software SYSTEM design. Yes,
Yourdon et al may seem old hat these days, but those principles of
hierarchy and cohesion that he and his 'school' preached are often
overlooked to our cost. The systemvscripts approach lacked any general
management management; error reporting and handling was up to each
script and it was more by coincidence that they used syslog! The 'do
this then do this then do this..." approach could not lend itself to
error MANAGEMENT or dependency management (aka hierarchy) without some
more ad-hoc gyrations.

There was little functional cohesion except for putting more and more -
overloading - in a single script. Each script being separate there was
no communication cohesion - a point that systemd quite specifically
addresses in its design. Temporal and procedural cohesion was forced
and unmanageable in the very nature of systemvscripts, there being no
clear, easy or manageable mechanism supporting parallelism

Much of the start up consists of activities that have little relation
relationship to each other once some basic things are in place such as
network having been started or the shared memory file system - /var/run,
/var/lock - having been started.

if we'd been using systemd for years and someone suggested replacing it
with systemvscripts there would be an outcry at the sheer stupidity and
incoherent ad-hoc nature of the way systemvscripts works.

Definitions are temporary verbalizations of concepts, and concepts --
particularly difficult concepts -- are usually revised repeatedly as our
knowledge and understanding grows.
-- Ernst Mayr
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