SystemImager automates the installation of Linux to masses of similar machines. Software distribution, configuration, and operating system updates are made easy, including updates from one Linux release to another. It can also be used for content distribution on Web servers. It is most useful in environments with large numbers of identical machines. Some typical environments include Internet server farms, high performance clusters, computer labs, and corporate desktop environments where all workstations have the same basic hardware configuration.
changedfiles is a framework for filesystem replication, security monitoring, and/or automatic file transformations--essentially any application where you'd poll files or directories and either do something to them or send them somewhere else (or both). The difference is that the kernel tells you when they change instead of you having to poll. It's an easy real time FTP push mirror to one or multiple sites. It's also a full fledged MySQL client, so you can do realtime database operations (for example, batch imports). It consists of two parts: a kernel module (works with Linux kernel version 2.4) which reports to a device whenever a file on the filesystem changes, and a daemon which runs in user space and can be configured to do almost any action when a change to a file matching the one of the patterns it looks for is reported. The kernel module is SMP safe and has been tested on Intel, PowerPC, and Alpha.