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JPS5525155A - Memory access system - Google Patents

Memory access system

Info

Publication number
JPS5525155A
JPS5525155A JP9822278A JP9822278A JPS5525155A JP S5525155 A JPS5525155 A JP S5525155A JP 9822278 A JP9822278 A JP 9822278A JP 9822278 A JP9822278 A JP 9822278A JP S5525155 A JPS5525155 A JP S5525155A
Authority
JP
Japan
Prior art keywords
memory
unit
decision
access
main memory
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.)
Granted
Application number
JP9822278A
Other languages
Japanese (ja)
Other versions
JPS6046745B2 (en
Inventor
Naoyoshi Minoda
Haruo Wakabayashi
Toshinori Ito
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.)
Fujitsu Ltd
NEC Corp
Nippon Telegraph and Telephone Corp
Original Assignee
Fujitsu Ltd
NEC Corp
Nippon Telegraph and Telephone Corp
Nippon Electric Co 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 Fujitsu Ltd, NEC Corp, Nippon Telegraph and Telephone Corp, Nippon Electric Co Ltd filed Critical Fujitsu Ltd
Priority to JP53098222A priority Critical patent/JPS6046745B2/en
Publication of JPS5525155A publication Critical patent/JPS5525155A/en
Publication of JPS6046745B2 publication Critical patent/JPS6046745B2/en
Expired legal-status Critical Current

Links

Landscapes

  • Storage Device Security (AREA)
  • Memory System (AREA)

Abstract

PURPOSE: To protect adequately a memory by a simple constitution by judging that write operations from CPU and a data channel are access to a specific are divided into a fixed number of words on a main memory unit.
CONSTITUTION: Main memory control circuit 2 of CPU1 is provided with protective memory 9 which makes a decision on whether the write operation from CPU1 and data channel 21 is access to specific areas on main memory units 41 and 42 and the detection circuit composed of gate circuits 14 and 17. Then, memory 9 is addressed by the outputs of address registers 4 and 23 which receive use permission signal 3 for CPU and use permission signal 22 for unit 21. To attain access to this memory 9 from unit 21, a signal detected by the detection circuit is sent back to unit 21 via gate 14 and then, decision circuit 25 mades a decision on whether the signal sent back from unit 21 is available or not, thereby performing accurately the memory protection of units 41 and 42.
COPYRIGHT: (C)1980,JPO&Japio
JP53098222A 1978-08-14 1978-08-14 Memory access method Expired JPS6046745B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP53098222A JPS6046745B2 (en) 1978-08-14 1978-08-14 Memory access method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP53098222A JPS6046745B2 (en) 1978-08-14 1978-08-14 Memory access method

Publications (2)

Publication Number Publication Date
JPS5525155A true JPS5525155A (en) 1980-02-22
JPS6046745B2 JPS6046745B2 (en) 1985-10-17

Family

ID=14213928

Family Applications (1)

Application Number Title Priority Date Filing Date
JP53098222A Expired JPS6046745B2 (en) 1978-08-14 1978-08-14 Memory access method

Country Status (1)

Country Link
JP (1) JPS6046745B2 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6232544A (en) * 1985-08-05 1987-02-12 Mitsubishi Electric Corp Abnormally detecting circuit for information processor

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3806882A (en) * 1971-11-22 1974-04-23 A Clarke Security for computer systems
JPS50128936A (en) * 1974-03-29 1975-10-11

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3806882A (en) * 1971-11-22 1974-04-23 A Clarke Security for computer systems
JPS50128936A (en) * 1974-03-29 1975-10-11

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6232544A (en) * 1985-08-05 1987-02-12 Mitsubishi Electric Corp Abnormally detecting circuit for information processor

Also Published As

Publication number Publication date
JPS6046745B2 (en) 1985-10-17

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