Abstract: An access control module restricts access to a computer system to authorized users and selectively controls each user's access to associated computer peripherals such as data storage units, printers, and communications equipment. During start-up of the computer system, a microprocessor associated with the module invokes a software routine that requests entry of a valid user identification code. In response to the code, the microprocessor retrieves from a main non-volatile storage unit pre-recorded information regarding the user's authority to access each of the peripherals, and loads the information into a secondary storage unit comprising random access memory and an address decoder adapted to retrieve data therefrom. Thereafter, the address decoder responds to each peripheral address signal generated in the input/output channel associated with the computer system and retrieves from the secondary storage unit the access information relating to the peripheral identified by the address signal.

Abstract: The invention relates to a process for the production of bands or sheets of isotropic mechanical properties from copper and copper alloys, such bands or sheets being subjectable to intensive cold shaping. According to the invention the ZrB.sub.2 (zirconium boride) content of the melted metal bath is adjusted by the addition of zirconium boride to a level between 0.01% by weight and 0.075% by weight, and if desired, not more than 50% by weight of the zirconium content of the added ZrB.sub.2 is replaced by one or more of the metals Ti, V, Nv, Ca, Mg and Co, then, if desired, zirconium is added to the metal bath in a stoichiometric ratio calculated for the lead content of the alloy exceeding 0.015% by weight, then the metal bath containing the additives is solidified in the form of a band, and if desired, an inert gas atmosphere is maintained in the heat stabilizing furnace of the casting equipment and/or an inert gas lock and secondary cooling are applied during the solidification of the metal bath.