PC Time Software
Time software falls into two major categories: (1) Clock time synchronization and rate correction, and (2) time displays.
Synchronization programs set the PC clock to an external standard. Although some programs permit manual synchronization (to a radio time station or audible time signal), increasingly, they dial up national standards and automatically synchronize. Network Time Protocol (NTP) servers are other synchronization sources. The tendency today is to use Internet time servers, which are controlled by atomic clocks.
Because PC clocks rarely have a correct rate (they lose or gain time significantly) it is useful to correct the rate with software that determines the rate error and then periodically corrects the time. In this way a typical rate error of several seconds per day can effectively be reduced to several seconds per month. This has the added advantage that synchronization need be performed less frequently.
For a discussion of PC clocks see the paper RighTime tm A Real Time Clock Correcting Program For MS-DOS-Based Computer Systems by Tom Becker.
The Global Positioning System (GPS), although designed for navigation, provides very precise time synchronization (to within one microsecond of Coordinated Universal Time (UTC). While plug-in GPS boards for time synchronization recently cost about $3000, GPS navigation receivers can be obtained for $300 or less, and it is anticipated that lower-cost time synchronization systems will become available.
Software may be a commercial product, shareware, or in the public domain. Shareware can be obtained free on a trial basis, but must be paid for after the trial period. Public domain software is free.
Shareware and public domain software is stored in computer archives from which it may be downloaded over the Internet and from numerous bulletin-board systems. It is additionally available on CD-ROMs from publishers such as Simtel and their distributors.
A software information retrieval system provided at shareware.com was originally developed as the Virtual Shareware Library (VSL) by Ziga Turk in Slovenia. It permits searching the contents of the above three and other archives using key words. For example, we have used the words "clocks" and "time" to locate a number of useful programs. Once software has been located, the VSL provides current Internet locations of mirror archives so that the software can then be downloaded via FTP (File Transfer Protocol).
Time Synchronization & Clock Correction Software
Several hundred time-related freeware and shareware programs for downloading. Includes synchronization software, alarm and time clocks, display and speaking clocks.
Tucows Time Synchronization Software Guides
Over a dozen shareware clock applications.
Commercial Programs and Shareware
The following are generally older programs, some archived on this site and no longer available elsewhere. Use of newer programs on the above software index sites is recommended.
Time Synchronization Software
Macintosh Time Software
Clock synchronization is built into the Macintosh operating system since Mac OS 8.5, that came out around November 1998 (current is Mac OS 8.5.1). It is therefore not necessary to install any programs for doing clock synchronization with a time server on the Internet. Instead you use the date and time control panel to choose time server etc. [Courtesy of Henrik Münster]
CLOCKS and TIME