Abstract: A scheduler in accord with the invention schedules available bit rate (ABR) traffic over an asynchronous transfer mode (ATM) link in such a manner as to provide circuits having the ABR traffic service a minimum cell rate (MCR) that may be greater than zero. The scheduler uses static scheduling information to schedule traffic for high priority services, such as constant bit rate service. The static information also specifies transmit opportunities for an ABR circuit, in a manner analogous to that for CBR traffic. The statically scheduled transmit opportunities provide a negotiated minimum cell rate that is greater than zero, for the ABR circuit. The scheduler maintains dynamic scheduling information, which it uses to schedule traffic in otherwise available transmit times. For example, the scheduler may use the dynamic information to create a work list of virtual circuit connections for ABR service. During any cell transmit time that is not used by a higher priority service (e.g.

Abstract: A polishing apparatus is a cluster type of apparatus having a plurality of units which perform various operations. The polishing apparatus includes a universal transfer robot having at least one arm for transferring a workpiece, a plurality of units disposed around the universal transfer robot and including a loading unit for receiving the workpiece to be polished, at least one polishing unit for polishing the workpiece, at least one washing unit for washing the workpiece which has been polished and an unloading unit for receiving the cleaned workpiece. Discrete mechanisms respectively transfer a clean workpiece and a dirty workpiece amongst the units.