JPS5480109A - Memory protection device in magnetic memory device being cross called - Google Patents

Abstract

PURPOSE: To provide a highly flexible protection device with a simple constitution by inquiring the memory protection information provided in each unit of memory information and the discrimination signals of a data processing unit under cross call for each bit and controlling rewriting.

CONSTITUTION: The series read-out signal of the protect information part formed by the binary signal corresponding to rewritable or not for each bit in the hardware use region of each unit having been recorded in a recording medium 1 is stored in the protect information shift register 21 of a cross call control cirvuit 2. On the other hand, when the number of the data processing unit under cross call of a cross call counter 25 is decoded with a decoder 26, the inquiry of the information of each bit of the register 21 and informaton whether the cross call by the counter 25 or not is accomplished by way of the NAND circuits 240, 241... of the same bit position assigned in the protect information and the rewriting comand signal is controlled by a NOR gate 27. Hence, the highly flexible memory protection device according to the protection information of the plural bits which may be combined as desired for each memory information unit may be obtained with the simple constitution.

COPYRIGHT: (C)1979,JPO&Japio