CaiCai is a network and services monitoring system. It performs tests for ping, DHCP, POP3, SMTP, FTP, etc. It does not require additional software installed on the remote side. It is fully configurable. It provides instant reports (via an HTML page), logs, statistics, and sound alarms.
CleverEye is an affordable availability monitoring suite for fundamental monitoring and reporting on network components, Web sites, databases, crucial user tasks, system health, and application transaction response times. It provides flexible, ready-made reports on real-time and historical system data for finding bottlenecks. Features include alerting, trend analysis, auto discovery, user management, network status map, SLA monitoring, and business level views.
Daemonzup is a server monitoring tool that will check if several services/daemons are up on a specific server. It is run from a cron job. If a daemon appears to be dead, it will send email to admins, plus it may also try to restart it. It is designed for GNU/Linux and depends on Perl. It can monitor whatever software is daemonized: apache, MySQL, SSH, cron, xinet, syslog, etc.
Diskus is a high-level hard drive diagnostic and limited repair tool. It checks the disk geometry by writing numbered IDs into the sectors of the hard drive. Later one can verify that these sector-IDs on the disk are still correct, thereby detecting data which was not correctly written. There is an option to "freshen" the data on your harddrive, which will read and rewrite the sectors. With modern drives this will re-map defective sectors.