US4471390A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Flexible diskette data duplication
Assignee: Kybe Corp
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Filing: 1982-06-25
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Granted: 1984-09-11
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Expires: 2002-06-25
Abstract
Abstract Apparatus for bit-by-bit duplication of data stored on a flexible diskette. A master disk is driven by a conventional DC drive, which provides a feedback control voltage responsive to the instantaneous speed of the master disk. A slave disk is driven from external index synchronization circuitry, which receives signals from the respective disk drives indicative of the angular position of the diskettes, and additionally receives the master drive control voltage. The index synchronization circuitry outputs a motor error correction voltage to the slave disk drive, thereby coordinating the rotation of the respective diskettes. Bits are copied only when the slave disk drive parameters fall within a narrowly defined window.
Inventors
- 👤 Robert W. Hamann
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:11
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/86
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
139 words
In combination with disk drives for rotating magnetically encodable master and slave disks subject to electronic control, means for producing a master control signal essentially representative of the instantaneous angular velocity of the master disk to control the rotation thereof, means associated with each disk drive for producing an index signal at a given angular position of the disk, and means for copying data stored on the master disk onto at least one slave disk: apparatus for controlling the copying of data, comprising means for producing a slave control signal representative of the master control signal, modified by said master and slave indices; means for adjusting the angular velocity of the slave disk in accordance with said slave control signal; and means for actuating the data copying means only when said master and slave indices have a predetermined relationship.
Claim 2
Dependent Claim
139 words
In combination with disk drives for rotating magnetically encodable master and slave disks subject to electronic control, means for producing a master control signal essentially representative of the instantaneous angular velocity of the master disk to control the rotation thereof, means associated with each disk drive for producing an index signal at a given angular position of the disk, and means for copying data stored on the master disk onto at least one slave disk: apparatus for controlling the copying of data, comprising means for producing a slave control signal representative of the master control signal, modified by said master and slave indices; means for adjusting the angular velocity of the slave disk in accordance with said slave control signal; and means for actuating the data copying means only when said master and slave indices have a predetermined relationship.
Claim 3
Dependent Claim
43 words
Apparatus as defined in claim 1, further comprising means for producing an error signal proportional to any phase differential between the master and slave indices, wherein the slave control signal is representative of the master control signal, modified by said error control signal.
Claim 4
Dependent Claim
24 words
Apparatus as defined in claim 2 wherein the error control signal comprises a ramp signal of amplitude and duration determined by said phase differential.
Claim 5
Dependent Claim
25 words
Apparatus as defined in claim 3 wherein the slave control signal is representative of the sum of the master control signal and the ramp signal.
Claim 6
Dependent Claim
22 words
Apparatus as defined in claim 2 wherein the error control signal is produced once during each rotation cycle of the master disk.
Claim 7
Dependent Claim
32 words
Apparatus as defined in claim 2 wherein said error signal is initiated by the earlier of the master and slave indices, and terminated by the later of the master and slave indices.
Claim 8
Dependent Claim
41 words
Apparatus as defined in claim 1 wherein the means for actuating the data copying means detects any phase differential between the master and slave indices, and actuates the data copying means only when the phase differential falls below a predetermined value.
Claim 9
Dependent Claim
15 words
Apparatus as defined in claim 1 wherein the master and slave indices comprise pulse trains.
Claim 10
Dependent Claim
52 words
Apparatus as defined in claim 8 wherein said actuating means comprises: means for producing an index synchronization pulse centered on a given edge of the master index pulse; and means for actuating the data copying means only when the corresponding edge of the slave control pulse falls within said index synchronization pulse.
Claim 11
Dependent Claim
19 words
Apparatus as defined in claim 9 wherein said index synchronization pulse and master control pulse are of comparable durations.
References Cited (Backward Citations)
US3805284A
Cited
US4375655A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-09-11 | 1988-03-12 | 1988-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-11 | 1992-03-12 | 1992-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-11 | 1996-03-12 | 1996-09-11 | $7700.00 | Window Closed / Lapsed |