Error detection/correction and fault detection/recovery – Data processing system error or fault handling – Reliability and availability
Reexamination Certificate
1998-10-20
2002-04-30
Ray, Gopal C. (Department: 2181)
Error detection/correction and fault detection/recovery
Data processing system error or fault handling
Reliability and availability
C360S053000, C711S112000
Reexamination Certificate
active
06381706
ABSTRACT:
FIELD OF THE INVENTION
The present invention pertains generally to data recording/recovery devices, and more particularly to a method for rewriting data that fails a check-after-write test to ensure data integrity.
BACKGROUND OF THE INVENTION
Data storage devices, which are used in both short- and long-term capacities, are an integral part of modern computer systems. While factors such as costs, device form factor, storage media size and capacity, and recording and recovery times are of high importance, of primary concern is the ability to maintain data integrity.
Accordingly, many tape drives include a check-after-write scheme whereby data is verified by a read head as the data is recorded onto the tape. For example, in a helical scan tape drive, in which data is written in tracks in an alternate-azimuth helical pattern by a pair alternate azimuth adjacent write heads mounted on a rotating drum, the newly recorded data is verified half a drum rotation later by a pair of alternate azimuth read heads located 180 degrees relative to the pair of write heads.
Whenever a check-after-write failure occurs, the write operation is suspended and the tape is repositioned backwards to allow enough space to accelerate again to the forward operating speed, and the track containing the “failed” data is overwritten by a new track on which the “failed” data is attempted to be rewritten. The failed data had to be rewritten before data which followed it in address sequence could be recorded onto the tape due to the format requirement calling for recording in-sequence.
The prior art backhitching sequence for rewriting “bad” data is problematic. First, the time required for a backhitching cycle increases data recording time and delays the host system by causing an interruption if data from the host had achieve a maximum throughput “streaming” mode. In addition, because backhitching induces extremely high transient forces that greatly increase tape wear and reduce the mechanical reliability of the drive, the backhitch operation can seriously impact data reliability.
The backhitching sequence can be avoided by simply rewriting tracks that contain “bad” data further down the tape without stopping the process. However, this methodology has the disadvantage that if the rewrite count is high, a significant portion of the tape is occupied by duplicate tracks containing mainly redundant “good” data, thereby reducing the storage capacity of the tape.
Accordingly, a need exists for a method for rewriting “bad” data without engaging in a backhitching sequence and without the overhead requirements of rewriting full mainly-redundant or mainly-empty tracks.
SUMMARY OF THE INVENTION
The present invention is a novel method and apparatus for performing rewrites at the packet level by allowing data to be recorded onto tracks on a magnetic media in any address sequence. Local packet address information is included in the track packet itself to allow track packets to be written to the storage medium in any addressing order. This allows a single packet to be rewritten along a later track among other track packets that are being recorded for the first time, thereby reducing rewrite track overhead and eliminating the requirement for a lengthy backhitching sequence.
REFERENCES:
patent: 3821710 (1974-06-01), Arciprete et al.
patent: 3962727 (1976-06-01), Kamimura et al.
patent: 4011587 (1977-03-01), Arter et al.
patent: 4099211 (1978-07-01), Hathaway
patent: 4106065 (1978-08-01), Ravizza
patent: 4125881 (1978-11-01), Eige et al.
patent: 4172265 (1979-10-01), Sakamoto et al.
patent: 4175267 (1979-11-01), Tachi
patent: 4215377 (1980-07-01), Norris
patent: 4257075 (1981-03-01), Wysocki et al.
patent: 4293879 (1981-10-01), Heitmann et al.
patent: 4357639 (1982-11-01), Hama et al.
patent: 4390915 (1983-06-01), Matsuyama
patent: 4394694 (1983-07-01), Ninomiya et al.
patent: 4404605 (1983-09-01), Sakamoto
patent: 4412260 (1983-10-01), Stricklin et al.
patent: 4420778 (1983-12-01), Sakamoto
patent: 4467373 (1984-08-01), Taylor et al.
patent: 4484236 (1984-11-01), Wilkinson
patent: 4486796 (1984-12-01), Sakamoto
patent: 4491886 (1985-01-01), Saito et al.
patent: 4492991 (1985-01-01), Osada et al.
patent: 4544967 (1985-10-01), Louth
patent: 4554598 (1985-11-01), Tarbox et al.
patent: 4581662 (1986-04-01), Sato
patent: 4609947 (1986-09-01), Yamagiwa et al.
patent: 4614991 (1986-09-01), Murakami
patent: 4620245 (1986-10-01), Shimizu
patent: 4628372 (1986-12-01), Morisawa
patent: 4628383 (1986-12-01), Miyamoto
patent: 4636873 (1987-01-01), Eguchi
patent: 4637023 (1987-01-01), Lounsbury et al.
patent: 4641210 (1987-02-01), Ohyama
patent: 4642714 (1987-02-01), Miyamoto
patent: 4644414 (1987-02-01), Yamada et al.
patent: 4651239 (1987-03-01), Omori et al.
patent: 4654731 (1987-03-01), Froschl et al.
patent: 4663673 (1987-05-01), Doutsubo
patent: 4665447 (1987-05-01), Odaka
patent: 4677504 (1987-06-01), Yamazaki et al.
patent: 4680654 (1987-07-01), Shibuya
patent: 4682247 (1987-07-01), Doutsbo
patent: 4688109 (1987-08-01), Sangu
patent: 4703373 (1987-10-01), Oosaka
patent: 4714971 (1987-12-01), Sigiki et al.
patent: 4717974 (1988-01-01), Baumeister
patent: 4731678 (1988-03-01), Takeuchi
patent: 4737865 (1988-04-01), Murakami et al.
patent: 4739420 (1988-04-01), Odaka et al.
patent: 4757911 (1988-07-01), Nakano et al.
patent: 4758904 (1988-07-01), Takashashi et al.
patent: 4760474 (1988-07-01), Takimoto
patent: 4769811 (1988-09-01), Eckberg, Jr. et al.
patent: 4774605 (1988-09-01), Kato
patent: 4786011 (1988-11-01), Fujiwara et al.
patent: 4796115 (1989-01-01), Ohshima et al.
patent: 4799221 (1989-01-01), Fukami et al.
patent: 4802172 (1989-01-01), Fukami et al.
patent: 4812924 (1989-03-01), Fukami et al.
patent: 4821129 (1989-04-01), Culp
patent: 4835628 (1989-05-01), Hinz et al.
patent: 4843495 (1989-06-01), Georgis et al.
patent: 4845577 (1989-07-01), Georgis et al.
patent: 4897739 (1990-01-01), Hasegawa et al.
patent: 4918546 (1990-04-01), Saito
patent: 4930027 (1990-05-01), Steele et al.
patent: 4933784 (1990-06-01), Oldershaw et al.
patent: 4935824 (1990-06-01), Nakano et al.
patent: 4935827 (1990-06-01), Oldershaw et al.
patent: 4970612 (1990-11-01), Renders et al.
patent: 4977469 (1990-12-01), Yokozawa
patent: 4984104 (1991-01-01), Takahashi et al.
patent: 5003411 (1991-03-01), Nagahara et al.
patent: 5034833 (1991-07-01), Marlowe
patent: 5050018 (1991-09-01), Georgis et al.
patent: 5068757 (1991-11-01), Hughes et al.
patent: 5103355 (1992-04-01), Steele
patent: 5115500 (1992-05-01), Larsen
patent: 5142422 (1992-08-01), Zook et al.
patent: 5191491 (1993-03-01), Zweighaft
patent: 5251077 (1993-10-01), Saitoh
patent: 5262905 (1993-11-01), Takagi et al.
patent: 5327035 (1994-07-01), Thomas
patent: 5341378 (1994-08-01), Shih
patent: 5349481 (1994-09-01), Kauffman et al.
patent: 5414570 (1995-05-01), Fry et al.
patent: 5493562 (1996-02-01), Lo
patent: 5535068 (1996-07-01), Hughes
patent: 5602694 (1997-02-01), Miles et al.
patent: 5623470 (1997-04-01), Asthana et al.
patent: 5633764 (1997-05-01), Ohta
patent: 5781688 (1998-07-01), Seong
patent: 5872997 (1999-02-01), Golson
patent: 5953177 (1999-09-01), Hughes
patent: 29 06 836 (1980-09-01), None
patent: 0 793 228 (1997-09-01), None
patent: 56-93157 (1981-07-01), None
patent: 58-133665 (1982-02-01), None
patent: 57-55579 (1982-04-01), None
patent: 59-139157 (1983-01-01), None
Pizzi, New Audio Recording Formats, Broadcast Engineering, Feb. 1993, paragraph. 60-63.
NT-1, Apr. 1992.
Sasake, T., Asltad, J.,Younker, M., The NT Digital Mcro Tape Recorder, Goddard Conference on Mass Storage Systems and Technologies, Sep. 22-24, 1992, paragraph. 143-157.
Clement Jessica
Ecrix Corporation
Fishman Daniel
Ray Gopal C.
LandOfFree
Fine granularity rewrite method and apparatus for data... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Fine granularity rewrite method and apparatus for data..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fine granularity rewrite method and apparatus for data... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2880245