JPS5455410A - Magnetic disc device - Google Patents
Magnetic disc deviceInfo
- 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
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
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)
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)
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 |
-
1977
- 1977-10-12 JP JP12278477A patent/JPS5455410A/en active Pending
Patent Citations (1)
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)
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 |