On Wed, Feb 19, 2020 at 1:51 AM Rafael Skodlar <ra...@linwin.com> wrote:
> > Think about LinuxCNC and it's packages. Using Slackware method you could > try to use different version of LCNC to see if it's good for your CNC > setup. If the new version fails (breaks your tool?) you could run > "cnc-admin script" to roll back, i.e. relink the app to previous version > and start it. > > /opt/linuxcnc-v2.6/bin <- binaries or scripts > /opt/linuxcnc-v2.6/etc <- config files > ... > > /opt/linuxcnc-v2.7/bin > /opt/linuxcnc-v2.7/etc > ... > What you suggest is not that simple. For starters, there are cross-package dependencies, so in general you will have to carry various system libraries required by each version. Then, modern programs use various forms of IPC, so they need version specific versions of those IPC endpoints (things like DBus, etc). IN the end, you can do it, but you replicate huge parts of the OS. RedHat/Fedora tried to do Modularity, which is something like what you propose except it turned out that you could have multi-version availability but not multiversion installability (it was easy to switch versions, but you could install only one). They put a lot of effort into making dependencies work automatically, but in the end it turns out that lifecycle management (patching/updating) is hard in a multi-version world: multiple versions of multiple programs lead to combinatorial explosion of dependencies and unresolvable conflicts when one program depends on ver. X of something and another one on ver. Y. Currently Modularity is in retreat. The technology to do that exists---containers like Docker or Podman. The downside is that your system is now a mess of versions, and you need to worry about patching and updating them. Containers provide a partial solution to the Modularity problems---you can isolate such conflicts to separate containers, but you still need to worry about lifecycle management. If you are serious about those issues, read up on containers and modularity---don't invent your own solutions, as a lot of people tried to do it right and it's worth to learn from their experiences. _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
