[OpenIndiana-discuss] from the lost to the river
thorsten.heit at vkb.de
Tue Oct 2 09:31:01 UTC 2012
> > I still don't know what IPS really is....
> "Image Packaging System"
> It's a software packaging scheme that was designed during the
> OpenSolaris days as a replacement for the old SysV packaging system.
> The big change is that it's based on a client/server model, where (at
> least in the first implementation) the server was a required part of the
> software upgrade mechanism.
> The old SysV packaging system had a disk format that delivered files,
> including scripts that ran at installation. IPS does not, and instead
> has a set of pre-determined actions that can be taken during upgrade or
> install of a file. The lack of scripting is an important improvement --
> the old scripting mechanisms allowed software developers to deliver
> arbitrary horrors inside scripts, but the new system doesn't allow that.
> OpenSolaris (and OpenIndiana) still supports SysV packaging, but the
> main software, at least in the main line of code, is delivered via IPS.
One big difference between IPS and the old SysV system:
A SysV package is one huge file whereas packages delivered via IPS are
split into lots of single files; simplified said: one file on your disk
from a certain package ^= one file in IPS, cryptographically signed in the
IPS manifest and stored in compressed form on the IPS server.
If you download a newer version of a SysV package, MySQL for example, you
normally have to suck the whole package, even when only a small part
inside the package was changed. IPS on the other hand will download only
the delta, i.e. those files that were changed.
Additionally the IPS server doesn't really care about the architecture of
your system; it can store files for different CPU architectures and
operating systems in one single repository. GlassFish for example is using
this technique (*).
Just my 0.02$ ;-)
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