A text processing device which includes a typewriter and a memory device, in which a comparison circuit is provided, by means of which a write/read connection between the memory device and the typewriter is completed as a function of the positive result of a comparison between a stored identification and an identification input by means of the typewriter keyboard, for the protection of stored text information against changes and unauthorized access by third parties.
A portable memory cartridge includes a mass memory, a data bus, an address bus, control signal lines for carrying signals for making access to the mass memory, a password memory for storing a flag indicating the inhibition of read/write access to the mass memory, a password memory for storing a particular authorized password, and a comparator for comparing an input password with the particular password set previously. Whe the comparison results in coincidence, a control signal required for the access is supplied to the mass memory for enabling the access to the mass memory in data read or write mode or data read and write mode.
A memory system for use in a text entry system is provided. The system includes a retentive data memory and a system for locking a portion of the retentive memory and a key for unlocking the lockable portion of the memory to allow a predetermined number of bits of data to be written to the memory when the lockable memory is in unlocked state. The system automatically locks the memory after the predetermined number of bits have been written into the lockable portion of memory.
A memory system for use in a text entry system is provided. The system includes a retentive data memory and a system for locking a portion of the retentive memory and a key for unlocking the lockable portion of the memory to allow a predetermined number of bits of data to be written to the memory when the lockable memory is in unlocked state. The system automatically locks the memory after the predetermined number of bits have been written into the lockable portion of memory.
There is provided a numerical control unit having a processor (102a), a control program memory (102b), a memory (102c) for storing files, and input means (102d) for accessing the files. The processor (102a), in accordance with the control program, processes externally entered control data to numerically control a machine connected thereto. The arrangement is such that the name of a file to be protected is stored in the memory (102c) of the numerical control unit and, the name of an object file is compared with the protected file name in the memory (102c), when a modification command and the name of the object file are entered from the input means (102d). Processing for modifying the file is executed, on the condition that there is a processing confirmation input from the input means (102d), when the object is a file protected file.
In a computer system in which a storage unit is accessed by a host computer, protection key information for each of a plurality of areas of a storage volume, is stored into the storage volume mounted in the storage unit. When the storage volume is mounted on the storage unit, the storage unit reads out protection key information stored in the storage volume and stores it into a memory provided in the storage unit. When an access request for one of the plurality of areas of the storage volume is received from the host computer, the access request is collated with the protection key information stored in the memory relating to the requested area, and the access request is permitted or inhibited in accordance with the collating result.
