US3579211A
Expired / Lapsed
US
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Read-after-write verification of data on magnetic storage medium
Assignee: Datel Corp
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Filing: 1968-10-11
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Granted: 1971-05-18
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Expires: 1988-10-11
Abstract
Abstract Verification of data recorded on a magnetic storage medium is accomplished by reversibly driving the medium past a common record/reproduce head in order to successively record and play back each character of information and to verify the data recorded by comparing the information played back with the input data supplied for recording.
Inventors
- 👤 Raymond B Larsen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:46
CPC Classifications
G; G06; G06F; G06F11/00; G06F11/07; G06F11/14; G06F11/1497; G11; G11B; G11B20/00; G11B20/10; G11B20/18; G11B20/1816
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
234 words
A read-after-write verification system for characters of information recorded serially in binary form on a movable magnetic storage medium comprising a common record/reproduce head including separate record and read circuits adapted to be selectively energized for recording and playback of information on the medium, respectively, a data shift register including means for loading a series of data bits defining each character into said register, means for sequentially transferring the bits from said register to said record circuit for recording in serial form on the medium by said head including means simultaneously storing the bits transferred for recording, a motor control circuit including motor drive means for reversibly driving the movable magnetic storage medium, activating means causing said motor drive means to advance the medium in one direction over a predetermined number of counts as each character is recorded on the medium and further causing said motor drive means to successively drive the recording medium first in the reverse direction and then in the forward direction over the character recorded, said read circuit being activated when the medium is successively driven either in the reverse or forward direction to read the character recorded, and comparison means for comparing the bits reproduced by said read circuit with the bits stored including means for generating an error signal whenever the bits reproduced from the medium do not correspond with the bits stored in said data shift register.
Claim 2
Dependent Claim
234 words
A read-after-write verification system for characters of information recorded serially in binary form on a movable magnetic storage medium comprising a common record/reproduce head including separate record and read circuits adapted to be selectively energized for recording and playback of information on the medium, respectively, a data shift register including means for loading a series of data bits defining each character into said register, means for sequentially transferring the bits from said register to said record circuit for recording in serial form on the medium by said head including means simultaneously storing the bits transferred for recording, a motor control circuit including motor drive means for reversibly driving the movable magnetic storage medium, activating means causing said motor drive means to advance the medium in one direction over a predetermined number of counts as each character is recorded on the medium and further causing said motor drive means to successively drive the recording medium first in the reverse direction and then in the forward direction over the character recorded, said read circuit being activated when the medium is successively driven either in the reverse or forward direction to read the character recorded, and comparison means for comparing the bits reproduced by said read circuit with the bits stored including means for generating an error signal whenever the bits reproduced from the medium do not correspond with the bits stored in said data shift register.
Claim 3
Dependent Claim
36 words
A system according to claim 1 wherein said means for storing each series of bits is operative to store the bits in said register for subsequent comparison in the same order as the bits are reproduced.
Claim 4
Dependent Claim
49 words
A system according to claim 1, further characterized by reproducing the character block when the medium is driven in the reverse direction, and rerecording the character block in response to an error signal when the medium is thereafter driven in the forward direction over the original character block recorded.
Claim 5
Dependent Claim
37 words
A system according to claim 1, further including means associated with said record/reproduce head for erasing characters recorded on the medium, said erasing means being activated in response to an error signal generated by said comparison means.
Claim 6
Dependent Claim
55 words
A system according to claim 1 wherein the medium is defined by a magnetic tape and said motor control circuit is defined by a digital pulse motor control circuit including a DC motor for reversibly driving the magnetic tape at a constant speed under the control of digital pulses generated by said motor control circuit.
Claim 7
Dependent Claim
170 words
In a system for recording characters each coded into a series of binary bits of information on a movable recording medium, the combination comprising: recording Means for recording each series of binary bits of information on the medium and reproducing means for reproducing each series of binary bits of information so recorded on the medium, storage means including means for loading each series of binary bits of information into said storage means and means for transferring each of said series of binary bits from the storage means to said recording means for recording on the movable recording medium, motor drive means for alternately and reversibly driving said medium in opposite directions for recording the binary bits of information transferred to said recording means and for reproducing the binary bits of information recorded, and comparing means for comparing each of the binary bits of information in each series reproduced from the medium with the corresponding series of binary bits of information in each series transferred from said storage means for recording.
Claim 8
Dependent Claim
170 words
In a system for recording characters each coded into a series of binary bits of information on a movable recording medium, the combination comprising: recording Means for recording each series of binary bits of information on the medium and reproducing means for reproducing each series of binary bits of information so recorded on the medium, storage means including means for loading each series of binary bits of information into said storage means and means for transferring each of said series of binary bits from the storage means to said recording means for recording on the movable recording medium, motor drive means for alternately and reversibly driving said medium in opposite directions for recording the binary bits of information transferred to said recording means and for reproducing the binary bits of information recorded, and comparing means for comparing each of the binary bits of information in each series reproduced from the medium with the corresponding series of binary bits of information in each series transferred from said storage means for recording.
Claim 9
Dependent Claim
63 words
In a system according to claim 6 wherein the movable recording medium is driven in opposite directions for a predetermined number of counts to successively record and to reproduce the binary bits of information in each character recorded, and means associated with said comparing means to generate an error signal when a character reproduced does not correspond with the information to be recorded.
Claim 10
Dependent Claim
41 words
In a system according to claim 7, further including means responsive to generation of an error signal to rerecord the binary bits of information in each character compared when the movable storage medium is reversed and driven in the one direction.
Claim 11
Dependent Claim
41 words
In a system according to claim 7, further including means responsive to generation of an error signal to erase the binary bits of information in the character recorded when the movable storage medium is reversed and returned in the one direction.
Claim 12
Dependent Claim
50 words
In a system according to claim 7, said motor drive means being operative in succession to advance the medium in a forward direction for recording each character, reverse the medium past the character recorded, and again reverse the medium to return in the forward direction and reproduce the character recorded.
Claim 13
Independent Claim
97 words
The method of verifying characters of information each coded into a series of binary bits recorded serially on a movable recording medium, comprising the steps of: serially recording the binary bits in each character of information on the recording medium, reversing the direction of movement of the recording medium and reading the binary bits in each character of information recorded, comparing the binary bits in each character block read with the corresponding binary bits in each corresponding character recorded, and generating an error signal whenever the character read does not correspond with the character to be recorded.
Claim 14
Independent Claim
97 words
The method of verifying characters of information each coded into a series of binary bits recorded serially on a movable recording medium, comprising the steps of: serially recording the binary bits in each character of information on the recording medium, reversing the direction of movement of the recording medium and reading the binary bits in each character of information recorded, comparing the binary bits in each character block read with the corresponding binary bits in each corresponding character recorded, and generating an error signal whenever the character read does not correspond with the character to be recorded.
Claim 15
Dependent Claim
39 words
The method of verifying data according to claim 11, comprising the additional step of advancing the recording medium in the one direction of movement and erasing the binary bits in each character recorded whenever an error signal is generated.
Claim 16
Dependent Claim
58 words
The method according to claim 11 being further characterized by the step of recording the binary bits in each character when the recording medium is advanced in the forward direction, reversing the direction of travel of the recording medium to its starting point and reading the binary bits in the character recorded in the same order as recorded.
Claim 17
Dependent Claim
47 words
The method according to claim 11 further characterized by erasing the recording medium over a predetermined number of counts, reversing the recording medium to write the binary bits in each character, and again reversing the recording medium to read the corresponding binary bits in each character recorded.
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) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |