Monit is a utility for managing and monitoring processes, programs, files, directories, and devices on a Unix system. It conducts automatic maintenance and repair and can execute meaningful causal actions in error situations. It can be used to monitor files, directories, and devices for changes, such as timestamps changes, checksum changes, or size changes. It is controlled via an easy to configure control file based on a free-format, token-oriented syntax. It logs to syslog or to its own log file and notifies users about error conditions via customizable alert messages. It can perform various TCP/IP network checks, protocol checks, and can utilize SSL for such checks. It provides an HTTP(S) interface for access.
Angel is a simple yet useful tool to monitor the services on your network. Technically speaking, it's a Perl program that runs every 'n' minutes (usually fired from your cron) and calls different perl subprograms (referred to as "plugins" from now on) to do the actual testing. It will then generate an HTML table containing the status of your network.
SNMP Monitor is a Tcl extension for monitoring static variables in routers or other agents using SNMP to access MIBs. The SNMP (Simple Network Management Protocol) uses polling or traps to communicate with the agent and the monitor equipment. MIBs are management information bases containing a wide range of interesting variables to be monitored.
pmacct is a small set of passive network monitoring tools to account, filter, classify, aggregate, and export IPv4 and IPv6 traffic. A pluggable and flexible architecture allows storing collected network data in memory tables, RDBMSs (MySQL, SQLite, PostgreSQL, BDB), and flat files, and also export via IPFIX, NetFlow, or sFlow protocols to remote collectors. pmacct features fully customizable historical data breakdown, sampling, BGP correlation, tagging, and triggers. Libpcap, ULOG, sFlow v2/v4/v5, NetFlow v1/v5/v7/v8/v9, and IPFIX are supported data capturing methods.
The Emu10k1 Driver for Linux supports Creative Labs' Emu10K1 chip, which is found in SoundBlaster Live! cards. It supports full duplex sound, two sound devices (dsp, dsp1), OSS compatibility, AC97, sndstat, MIDI, a Joystick interface and more than one EMU10k1 board in one computer. It does not yet support SMP.