JPS56123048A - Data destruction preventing circuit - Google Patents

Data destruction preventing circuit

Info

Publication number
JPS56123048A
JPS56123048A JP2405580A JP2405580A JPS56123048A JP S56123048 A JPS56123048 A JP S56123048A JP 2405580 A JP2405580 A JP 2405580A JP 2405580 A JP2405580 A JP 2405580A JP S56123048 A JPS56123048 A JP S56123048A
Authority
JP
Japan
Prior art keywords
maintenance
cylinders
fixed information
write
cylinder
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
JP2405580A
Other languages
Japanese (ja)
Inventor
Hideo Mitarai
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 JP2405580A priority Critical patent/JPS56123048A/en
Publication of JPS56123048A publication Critical patent/JPS56123048A/en
Pending legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F12/00—Accessing, addressing or allocating within memory systems or architectures
    • G06F12/14—Protection against unauthorised use of memory or access to memory

Abstract

PURPOSE:To prevent destruction of data of fixed information on cylinders except the maintenance cylinder, by petmitting the write to the maintenance cylinder even under the write inhibition state only when the address of the maintenance cylinder is detected. CONSTITUTION:The magnetic disc consists of cylinders for maintenance and cylinders for fixed information. Read only/write enable switch 4 is set to the read only state (write inhibition), and the address of a maintenance cylinder is detdcted by gate 2, and output 2a is generated. At this time, the output of flip flop 7 becomes the write enable state, and the device becomes writable. Next, when a cylinder (where fixed information is recorded) except maintenance cylinders where fixed information is recorded is prevented.
JP2405580A 1980-02-29 1980-02-29 Data destruction preventing circuit Pending JPS56123048A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2405580A JPS56123048A (en) 1980-02-29 1980-02-29 Data destruction preventing circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP2405580A JPS56123048A (en) 1980-02-29 1980-02-29 Data destruction preventing circuit

Publications (1)

Publication Number Publication Date
JPS56123048A true JPS56123048A (en) 1981-09-26

Family

ID=12127769

Family Applications (1)

Application Number Title Priority Date Filing Date
JP2405580A Pending JPS56123048A (en) 1980-02-29 1980-02-29 Data destruction preventing circuit

Country Status (1)

Country Link
JP (1) JPS56123048A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6233365A (en) * 1985-08-03 1987-02-13 Pioneer Electronic Corp Information recording and reproducing device

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6233365A (en) * 1985-08-03 1987-02-13 Pioneer Electronic Corp Information recording and reproducing device

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