Tascha is a schema incorporating both tables and PL/SQL code that utilises Oracle's dbms_job package to simplify and extend the process of executing, monitoring and logging of scheduled tasks.
It basically works as a dbms job that wakes up every minute and has a look at a list of scheduled tasks. A task is a PL/SQL procedure and a set of input parameters. All actions are logged and a notification email can be sent upon success or failure.
Most users of Oracle's dbms_job package will end up writing their own utility code to make the handling of jobs much simpler. They will probably also write in some kind of logging facility for their scheduled tasks to use. Then there's the handling and tracking of errors to take into account.
Tascha is intended to be a single application written to fulfill these little functions leaving you to concentrate on your tasks and not how you are going to call them. It runs inside the same Oracle instance as the tasks it schedules so wherever the database goes - Tascha goes too. Avoiding server specifics such as cron.
See the features below for more reasons.