Abstract: A technique involves trapping a command-not-found message instead of displaying it when an erronous command is entered at a user terminal and connecting it to a translation file of successful command signals which is searched for a match. There are several alternatives including displaying a failing command signal for editing, verification, review or confirmation. If a match is revealed, a substitute command signal can be displayed also for these activities.

Abstract: A selectable adder/hashing circuit generates a hashed virtual address from address operands within or derived from a program instruction. The hashed virtual address is used to address a translation lookaside buffer (TLB). The hashing function and addition function each comprise multiple steps. Some of the hashing function steps are performed in parallel with some of the steps of the addition function, and other of the hashing function steps are performed within other of the addition function steps. Therefore, the hashing function does not add delay over that required to produce an un-hashed virtual address from an addition function performed on the address operands. The hashing function can be enabled or disabled to meet the needs of the particular program environment. A method for generating the un-hashed address from the hashed address determines if the contents of the TLB location addressed by the hashed address match the unhashed virtual address.