US3893178A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Synchronization of multiple disc drives
Assignee: Information Storage Systems Inc
•
Filing: 1973-12-19
•
Granted: 1975-07-01
•
Expires: 1993-12-19
Abstract
Abstract A control system for synchronizing the rotation of the recording discs of a plurality of disc drives so that the read/write heads of all of the drives will be at the same relative position on the rotating discs thereby reducing the latentcy time in switching between disc drives.
Inventors
- 👤 Frank J Sordello
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 02:03
CPC Classifications
G; G11; G11B; G11B19/00; G11B19/20; G11B19/28; G11B27/00; G11B27/002; G11B27/10; G11B27/19; G11B27/24; G11B2220/00; G11B2220/20
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
99 words
A disc drive subsystem having a plurality of rotating discs each having an index point utilized to assist in the location of specific locations radially about the discs, including: adjustable drive means for rotating the discs at desired rotational speeds; means to signal the arrival of each index point at a predetermined location on the drive, and circuit means to detect the relative position of the index points and regulate the speeds of the drive means to adjust the speed of rotation of the discs thereby to cause the index points to arrive at the respective predetermined locations concurrently.
Claim 2
Dependent Claim
99 words
A disc drive subsystem having a plurality of rotating discs each having an index point utilized to assist in the location of specific locations radially about the discs, including: adjustable drive means for rotating the discs at desired rotational speeds; means to signal the arrival of each index point at a predetermined location on the drive, and circuit means to detect the relative position of the index points and regulate the speeds of the drive means to adjust the speed of rotation of the discs thereby to cause the index points to arrive at the respective predetermined locations concurrently.
Claim 3
Dependent Claim
58 words
A disc drive subsystem as defined in claim 1 wherein one drive means is the master and all other drive means are slaves, and the circuit means is adapted to regulate the speed of rotation of the slave drive means to cause the index points to arrive at the respective predetermined locations concurrently with the master drive means.
Claim 4
Dependent Claim
76 words
A disc drive subsystem as defined in claim 2 wherein the circuit means to detect the relative position of the index points includes means to generate a voltage signal having a positive or negative polarity depending on whether the master or slave index signal occurs first, and having a magnitude depeNdent on the time differential between the points, and means to regulate the slave drive motor speed in response to the voltage signal magnitude and polarity.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-06-30 | 1978-12-30 | 1979-07-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-06-30 | 1982-12-30 | 1983-07-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-06-30 | 1986-12-30 | 1987-07-01 | $7700.00 | Window Closed / Lapsed |