Many Web applications need to execute periodic
tasks. Some operating systems come with
programs, like cron or at, to execute scheduled
tasks. However, under some Web hosting
environments these programs cannot be used.
Virtual Cron provides an alternative solution that
can be used in more restricted hosting
environments. It uses files to keep track of the last
time when a periodical task was executed. The site
Web page scripts can use the class to check these
files. The class can tell when it is time to execute a
task again. When it is time, the same script can
execute the scheduled task without depending on
external programs.
