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JPS55135952A - Memory protection system - Google Patents

Memory protection system

Info

Publication number
JPS55135952A
JPS55135952A JP4306979A JP4306979A JPS55135952A JP S55135952 A JPS55135952 A JP S55135952A JP 4306979 A JP4306979 A JP 4306979A JP 4306979 A JP4306979 A JP 4306979A JP S55135952 A JPS55135952 A JP S55135952A
Authority
JP
Japan
Prior art keywords
key
memory
register
area
optional
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP4306979A
Other languages
Japanese (ja)
Inventor
Kenji Hayashi
Hiroo Miyadera
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP4306979A priority Critical patent/JPS55135952A/en
Publication of JPS55135952A publication Critical patent/JPS55135952A/en
Pending legal-status Critical Current

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  • Storage Device Security (AREA)

Abstract

PURPOSE: To make the memory capacity for a memory protective key very small, by deciding an address range to each continuous optional memory area which is desired, and allocating one key to the optional area, in case of protecting the main memory.
CONSTITUTION: To the register 10 is set a logical address which is used in case the processing device refers to the main memory, and a register 11 consists of one pair in which the first and the last addresses of the program are set. And the contents of the registers 10 and 11 are compared 12, its result is judged 13, its output is input to the selector circuit 15, one key corresponding to the related area among the keys in the register 14 is selected, is input to the judgement circuit 17, and when the reference has been approved, an approval signal is output. Thus, it is possible to make the memory capacity for the key very small by allocating one key to an optional area.
COPYRIGHT: (C)1980,JPO&Japio
JP4306979A 1979-04-11 1979-04-11 Memory protection system Pending JPS55135952A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP4306979A JPS55135952A (en) 1979-04-11 1979-04-11 Memory protection system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP4306979A JPS55135952A (en) 1979-04-11 1979-04-11 Memory protection system

Publications (1)

Publication Number Publication Date
JPS55135952A true JPS55135952A (en) 1980-10-23

Family

ID=12653558

Family Applications (1)

Application Number Title Priority Date Filing Date
JP4306979A Pending JPS55135952A (en) 1979-04-11 1979-04-11 Memory protection system

Country Status (1)

Country Link
JP (1) JPS55135952A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0314053A (en) * 1989-06-12 1991-01-22 Toshiba Corp Portable medium

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0314053A (en) * 1989-06-12 1991-01-22 Toshiba Corp Portable medium

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