JPS5455410A - Magnetic disc device - Google Patents

Magnetic disc device

Info

Publication number
JPS5455410A
JPS5455410A JP12278477A JP12278477A JPS5455410A JP S5455410 A JPS5455410 A JP S5455410A JP 12278477 A JP12278477 A JP 12278477A JP 12278477 A JP12278477 A JP 12278477A JP S5455410 A JPS5455410 A JP S5455410A
Authority
JP
Japan
Prior art keywords
track
switch
disc
effecting
maintenance
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
JP12278477A
Other languages
Japanese (ja)
Inventor
Koichi Yamamoto
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.)
NEC Corp
Original Assignee
NEC 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 NEC Corp, Nippon Electric Co Ltd filed Critical NEC Corp
Priority to JP12278477A priority Critical patent/JPS5455410A/en
Publication of JPS5455410A publication Critical patent/JPS5455410A/en
Pending legal-status Critical Current

Links

Landscapes

  • Signal Processing For Digital Recording And Reproducing (AREA)

Abstract

PURPOSE: To make the data protecting function complete by effecting the selection between the whole track accessible mode and the mode, in which no track other than a special one is accessible.
CONSTITUTION: The magnetic disc is composed of: a key switch 1; a detector 2 for judging the addresses of the 0 track, which is taken by a positioner under the initial condition of the disc device, and an inspection track for maintenance; a resistor 3 for setting a cylinder address; a one shot 4 which is controlled by the switch 1; and a leak control circuit 5 for effecting leak control in accordance with the cylinder address. If the switch 1 is set under a conductive condition when in the operation other than a normal operation, the positioner is positioned in the 0 track. Thereafter, access is not possible other than the 0 track and the inspecting track for maintenance. If the key is removed after the switch is set, the data on the disc are protected
COPYRIGHT: (C)1979,JPO&Japio
JP12278477A 1977-10-12 1977-10-12 Magnetic disc device Pending JPS5455410A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP12278477A JPS5455410A (en) 1977-10-12 1977-10-12 Magnetic disc device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP12278477A JPS5455410A (en) 1977-10-12 1977-10-12 Magnetic disc device

Publications (1)

Publication Number Publication Date
JPS5455410A true JPS5455410A (en) 1979-05-02

Family

ID=14844517

Family Applications (1)

Application Number Title Priority Date Filing Date
JP12278477A Pending JPS5455410A (en) 1977-10-12 1977-10-12 Magnetic disc device

Country Status (1)

Country Link
JP (1) JPS5455410A (en)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57191809A (en) * 1981-05-21 1982-11-25 Nec Corp Magnetic tape device
JPS57191808A (en) * 1981-05-21 1982-11-25 Nec Corp Magnetic tape control system
JPH04506428A (en) * 1989-07-10 1992-11-05 マーチン・マリエッタ・エナジー・システムズ・インク Multilayer protection system for computer hard disks
US5553954A (en) * 1993-11-10 1996-09-10 Citizen Watch Co., Ltd. Printer
JPH09138733A (en) * 1995-11-14 1997-05-27 Hokkaido Nippon Denki Software Kk Protective system for magnetic disk device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5237412A (en) * 1975-09-20 1977-03-23 Sanyo Electric Co Ltd Protective system for memory unit

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5237412A (en) * 1975-09-20 1977-03-23 Sanyo Electric Co Ltd Protective system for memory unit

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS57191809A (en) * 1981-05-21 1982-11-25 Nec Corp Magnetic tape device
JPS57191808A (en) * 1981-05-21 1982-11-25 Nec Corp Magnetic tape control system
JPH04506428A (en) * 1989-07-10 1992-11-05 マーチン・マリエッタ・エナジー・システムズ・インク Multilayer protection system for computer hard disks
US5553954A (en) * 1993-11-10 1996-09-10 Citizen Watch Co., Ltd. Printer
JPH09138733A (en) * 1995-11-14 1997-05-27 Hokkaido Nippon Denki Software Kk Protective system for magnetic disk device

Similar Documents

Publication Publication Date Title
JPS5455410A (en) Magnetic disc device
JPS5247343A (en) Test equipment for program control apparatus
JPS5453509A (en) Magnetic disc apparatus
JPS53121429A (en) Duplex memory unit
JPS5381103A (en) Preventing device for false insertion of recording disk in autoplayer
JPS5232236A (en) Testing device for interrupt processing circuit
JPS5223323A (en) Key switch operation detecting method
JPS5454009A (en) Data protecting device
JPS5673361A (en) Testing device of ic
JPS534442A (en) Information processing unit
JPS5417723A (en) Checking method of expulsion of originals of copying machines
JPS5235545A (en) Micro-program control device
JPS5296834A (en) Electronic computer
JPS5350940A (en) Test method for display unit
JPS5276507A (en) Turbine valve control device
JPS5362951A (en) Logical state inverstigation device
JPS53113447A (en) Information processor
JPS56123048A (en) Data destruction preventing circuit
JPS52129250A (en) Function test method for logical circuit
JPS5210767A (en) Clock tester
JPS52117041A (en) Integrating circuit function test unit
JPS57119267A (en) Checking device for logic operating condition
JPS5694453A (en) Test signal generating device
JPS51134196A (en) Retrieval unit for money adjustment device
JPS5329630A (en) Computer system for control