Software Updating

The original version of LCFG used a program called lfu [2] to update software on the local disks. At that time, clients tended to have smaller disks and mount much of their software from the network, so lfu was mainly concerned with synchronising a comparatively small number of replicated servers, and the performance would be poor for a large number of clients. There was also no obvious candidate for a package format which was widely supported by the packages that we wanted to install; lfu provides a crude mechanism for matching files to their packages, based on file ownership, but this was not always adequate. More importantly, it was also difficult to keep track of the link between binaries and their corresponding sources.

In theory, lfu could have been used under Linux, but the Redhat distribution is based on the RPM package management software which provides a much better mechanism for managing software packages. Many of the packages that we require are also distributed in this format.

Although there are now numerous programs available for updating and distributing RPMS (for example [13,11,5,10]), few of these tools were available in 1997. We also wanted to interface with the LCFG and provide automatic installation, upgrade and deletion of RPMs. The Linux version of LCFG therefore uses a locally-developed program called updaterpms. This is currently written in C and makes use of rpmlib ²(rewriting this in Python is a possibility now that there an rpmlib interface available).

Footnotes

...rpmlib ²

The latest version of updaterpms needs a modified version of rpmlib to support per-package options