Advanced Reservations and Dedicated Time are two technologies used for creating
special queues within PBS. Advanced Reservations is a functionality that allows users to submit a request for resources on a PBS complex for a given time and usually with a specific set of users. Dedicated Time is a way for site administrators to set up queues in PBS with the prefix "ded". An adminstator will additionally setup the times during which only jobs from queues prefixed with "ded" will run. This means that all other queues
will temporarily no long be considered during each scheduling cycle when PBS attempts to determine which jobs to run.

The core difference here is that Advanced Reservations are a user submit request for resouces that if granted is granted in the form a queue that does not distrupt the scheduling of jobs from any other queues in the system. Advanced Reservations simply
reserves a small set of resources and restricts job submitted to the reservation queue to run on those resources only.

Dedicated time on the other hand is essentially a system wide "pause" button that dedicates all the system resources to run jobs from specific queues. This can be useful for high priority processing that must occur on some known schedule.

It is important to note that jobs submitted to dedicated time queues MUST have a walltime or they will not run. It is also important to note that jobs queued to an advanced reservation queue will be deleted at the end of the reservation.