Abstract: Removal of selected, isolated defects comprised of excess chromium (Cr) or chromium oxide (Cr.sub.2 O.sub.3) from photomasks comprises contacting at least the defect area by a suitable acid and initiating the etch of the defect area by contacting the defect area with a metal probe made from a suitable material. Excess chromium or chromium oxide areas may be isolated by using a laser to separate the areas from areas which are to remain.

Abstract: Apparatus for signalling the occurrence of a match between an address that is supplied to a control store and an address that is to be watched for in a data processing system that executes several instruction streams concurrently. The apparatus signals the occurrence of a storage accessing operation at a location that is uniquely identified only by a virtual address that is longer than the actual address used in accessing the store. Means is provided for comparing the actual address used in accessing the store with the corresponding portion of the complete address, and means is provided for recording the location of an address to be watched for in a particular frame of the store and for signalling a match that occurs in such a frame. The apparatus is useful for testing the operation of the data processing system by relating a recurring malfunction of the system to the execution of an instruction at the address that is watched for.

Abstract: Protection for service lines linking offices in a communications system is realized by linking the offices in a sequence with a serial connection of protection lines. Protection for service lines which bypass one or more of the offices in the serial sequence is achieved by automatically controllably cascading appropriate ones of the protection lines. The cascading of protection lines is realized on a nonhierarchical basis by assigning each service line in the system a unique address and by supplying a protection switch request message including the address of the requesting service line sequentially to each office in the serial sequence until the transmit-end of the requesting line is located. A switch is automatically effected by equipment located at the offices only if all the protection lines to be cascaded are available.