WO2001027924A1 - Method for detecting transient write errors in a disk drive and for differentiating transient write errors from permanent media damage - Google Patents
Method for detecting transient write errors in a disk drive and for differentiating transient write errors from permanent media damage Download PDFInfo
- Publication number
- WO2001027924A1 WO2001027924A1 PCT/US2000/025889 US0025889W WO0127924A1 WO 2001027924 A1 WO2001027924 A1 WO 2001027924A1 US 0025889 W US0025889 W US 0025889W WO 0127924 A1 WO0127924 A1 WO 0127924A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- data
- disk
- data section
- write
- read
- Prior art date
Links
Classifications
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/10—Digital recording or reproducing
- G11B20/18—Error detection or correction; Testing, e.g. of drop-outs
- G11B20/1816—Testing
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/10—Digital recording or reproducing
- G11B20/18—Error detection or correction; Testing, e.g. of drop-outs
- G11B20/1879—Direct read-after-write methods
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B20/00—Signal processing not specific to the method of recording or reproducing; Circuits therefor
- G11B20/10—Digital recording or reproducing
- G11B20/18—Error detection or correction; Testing, e.g. of drop-outs
- G11B20/1816—Testing
- G11B2020/1823—Testing wherein a flag is set when errors are detected or qualified
-
- G—PHYSICS
- G11—INFORMATION STORAGE
- G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
- G11B2220/00—Record carriers by type
- G11B2220/20—Disc-shaped record carriers
Definitions
- the present invention is directed to a method of verifying the integrity of data written to a disk in a disk drive system, comprising: writing a first data section to a portion of the disk; periodically reading a pre-recorded signal from the disk; if the pre-recorded signal is substantially different from a predetermined value, reading the first data section written to the disk; and if the first data section read from the disk is substantially different from the first data section written to the disk, determining whether the portion of the disk is damaged.
- Another exemplary method of verifying the integrity of data written to a disk in a disk drive system in accordance with the present invention comprises: receiving a write request to write a first data section to a portion of the disk; determining whether the first data section comprises fewer than 64 blocks of data; disabling a write cache if the first data section comprises fewer than 64 blocks of data; writing the first data section to a portion of the disk; periodically reading a pre-recorded signal from the disk; if the pre-recorded signal is substantially different from a predetermined value, reading the first data section written to the disk; and if the first data section read from the disk is substantially different from the first data section written to the disk, determining whether the portion of the disk is damaged.
- FIGS. 6 A and 6B are flow charts representing an exemplary method in accordance with the present invention.
- FIG. 1 is a representation of a disk drive mechanism wherein the operation of the present invention may be illustrated.
- a disk 12 rotates about a spindle motor axis 14.
- the surface of the disk 12 is receptive to electromagnetic signals for storing data.
- Read/write electronics, embedded within slider bearing 16 generates an electromagnetic signal to write data and read an electromagnetic signal from the disk surface to read data.
- the slider bearing 16 with embedded read/write electronics is also referred to herein as a read/write head 16.
- the read/write head 16 is attached to arm 18.
- the head 16 and arm 18 assembly are attached to suspension 20. To access selected data sections, the arm 18 with attached read/write head 16 moves over the surface of disk 12 both reading and writing data as required.
- FIG. 2 is a graph of the normalized strength of the electromagnetic signal on the disk surface versus the flying height of the read/write head 16. Line 22 plots the relationship between these two variables. Significantly, there is an inverse relationship between the two variables. Thus, increases in flying height correspond to decreases in normalized signal strength.
- the flying height between the read/write head 16 and the surface of disk 12 reaches approximately between 0.04 and 0.1 ⁇ m, depending on the disk drive system, for a properly functioning full spinning disk 12. As illustrated in FIG. 2 by line 22, such a flying height corresponds to approximately 80 percent of the normalized signal strength.
- the flying height increase is transient, the data section can be re-read and the data recovered. In other words, the signal on the surface of the disk 12 was written properly, but a transient increase in flying height caused the read/write head 16 to deviate too far from the surface to properly read the data.
- the flying height exceeds 0.4 ⁇ m the signal strength rapidly diminishes to zero.
- each sector 33 is demarcated along the track with a header 36 and a trailer 38 that is recorded onto the disk surface.
- the header contains overhead information, such as constant density recording ("cdr") field (indicating how many bytes to the next servo field), track id field (identifying all sectors on the same logical track), sector id field (identifying a particular sector) and id error correction code field (containing an error correction code for cdr, track id and sector id fields).
- the number of sectors per track may vary, e.g., the innermost track may have 90 sectors per track, while the outermost track has 150 sectors per track. However, the number of servo fields remains the same for each track. For example, servo marks may appear every 3 degrees around each track. Servo marks contain a grey code (containing the physical track number), and norm and quad fields (indicating the head distance from the track center).
- the norm and quad fields of the servo marks are checked against a predetermined amplitude. If a mismatch occurs, a position error will be reported indicating how far the heads are from the center of the track.
- transient changes in head flying height during writes to disk 12 could result in a permanent signal loss. That is, as the flying height increases, the signal recorded on the media decreases. Thus, if the flying height crosses a threshold point, which may vary based on such factors as recording media and head type, the signal would not be recoverable on subsequent read operations. Unfortunately in such a case, the error may not be discovered until much later and permanent data loss could result.
- a feature of the present invention detects and corrects write errors caused by transient increases in flying height with a minimal impact on drive performance. This feature exploits the need for the drive to continue to read information, such as servo marks, from the disk 12 even during write operations. Therefore, flying height increases that persist while the read/write head is flying above portions of the disk 12 having pre-recorded signals, such as a servo mark, are detected and corrected. In particular, because some information, such as servo marks, was written and verified prior to the use of the disk 12, read signal degradation detected during track following and sector seeking likely resulted from flying height increases. In accordance with one aspect of the present invention, the data previously written is re-read and verified. As a result, a high quality write operation can be performed while only verifying a minimal amount of data.
- the signal strength degrades in the data sections 32a, 32b of FIG. 4. That signal weakness corresponds to an increase in head flying height during the write operation.
- the pre-recorded information such as servo marks 34 and sector headers 36a, 36b remain at pre-recorded signal levels.
- the data recorded therein will likely be unreadable and unrecoverable if it remains uncorrected.
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP00965249A EP1149380A1 (en) | 1999-10-07 | 2000-09-21 | Method for detecting transient write errors in a disk drive and for differentiating transient write errors from permanent media damage |
KR1020017007122A KR20010101145A (en) | 1999-10-07 | 2000-09-21 | Method for detecting transient write errors in a disk drive and for differentiating transient write errors from permanent media damage |
AU75993/00A AU7599300A (en) | 1999-10-07 | 2000-09-21 | Method for detecting transient write errors in a disk drive and for differentiating transient write errors from permanent media damage |
JP2001530858A JP2003511813A (en) | 1999-10-07 | 2000-09-21 | Method for detecting transient write errors in disk drives and distinguishing between transient write errors and permanent media damage |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US41419999A | 1999-10-07 | 1999-10-07 | |
US09/414,199 | 1999-10-07 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2001027924A1 true WO2001027924A1 (en) | 2001-04-19 |
Family
ID=23640395
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/US2000/025889 WO2001027924A1 (en) | 1999-10-07 | 2000-09-21 | Method for detecting transient write errors in a disk drive and for differentiating transient write errors from permanent media damage |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP1149380A1 (en) |
JP (1) | JP2003511813A (en) |
KR (1) | KR20010101145A (en) |
AU (1) | AU7599300A (en) |
TW (1) | TW513696B (en) |
WO (1) | WO2001027924A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002005279A1 (en) * | 2000-07-12 | 2002-01-17 | Iomega Corporation | Method for detecting transient write errors in a disk drive having a dual transducer slider |
GB2385978B (en) * | 2001-05-22 | 2004-11-24 | Seagate Technology Llc | Low amplitude skip write detector |
GB2415082A (en) * | 2003-11-28 | 2005-12-14 | Hitachi Ltd | Storage system comprising a controller which performs a read-after-write check |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US8189439B2 (en) * | 2010-07-16 | 2012-05-29 | Mediatek Inc. | Data recording method and apparatus for re-verifying correctness of recorded data on optical storage medium |
Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0490400A1 (en) * | 1990-12-14 | 1992-06-17 | Matsushita Electric Industrial Co., Ltd. | Information storage apparatus |
US5471351A (en) * | 1993-07-09 | 1995-11-28 | Fujitsu Limited | Method and apparatus of verifying accurate writing through comparisons of written and read data |
US5588007A (en) * | 1996-04-26 | 1996-12-24 | Iomega Corporation | Method for detecting transient write errors in a disk drive |
GB2326755A (en) * | 1997-06-03 | 1998-12-30 | Samsung Electronics Co Ltd | Method of establishing the capacity of a hard disk drive |
US6094318A (en) * | 1997-04-08 | 2000-07-25 | Samsung Electronics Co., Ltd. | Method and apparatus for controlling data write operation according to flying height of transducer head |
-
2000
- 2000-09-21 KR KR1020017007122A patent/KR20010101145A/en not_active Application Discontinuation
- 2000-09-21 AU AU75993/00A patent/AU7599300A/en not_active Abandoned
- 2000-09-21 JP JP2001530858A patent/JP2003511813A/en active Pending
- 2000-09-21 WO PCT/US2000/025889 patent/WO2001027924A1/en not_active Application Discontinuation
- 2000-09-21 EP EP00965249A patent/EP1149380A1/en not_active Withdrawn
- 2000-10-07 TW TW089120977A patent/TW513696B/en active
Patent Citations (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP0490400A1 (en) * | 1990-12-14 | 1992-06-17 | Matsushita Electric Industrial Co., Ltd. | Information storage apparatus |
US5471351A (en) * | 1993-07-09 | 1995-11-28 | Fujitsu Limited | Method and apparatus of verifying accurate writing through comparisons of written and read data |
US5588007A (en) * | 1996-04-26 | 1996-12-24 | Iomega Corporation | Method for detecting transient write errors in a disk drive |
US6094318A (en) * | 1997-04-08 | 2000-07-25 | Samsung Electronics Co., Ltd. | Method and apparatus for controlling data write operation according to flying height of transducer head |
GB2326755A (en) * | 1997-06-03 | 1998-12-30 | Samsung Electronics Co Ltd | Method of establishing the capacity of a hard disk drive |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2002005279A1 (en) * | 2000-07-12 | 2002-01-17 | Iomega Corporation | Method for detecting transient write errors in a disk drive having a dual transducer slider |
US6578164B1 (en) | 2000-07-12 | 2003-06-10 | Iomega Corporation | Method for detecting transient write errors in a disk drive having a dual transducer slider |
GB2385978B (en) * | 2001-05-22 | 2004-11-24 | Seagate Technology Llc | Low amplitude skip write detector |
GB2415082A (en) * | 2003-11-28 | 2005-12-14 | Hitachi Ltd | Storage system comprising a controller which performs a read-after-write check |
GB2415082B (en) * | 2003-11-28 | 2006-08-09 | Hitachi Ltd | Storage system comprising a controller which performs a read-after-write check |
Also Published As
Publication number | Publication date |
---|---|
KR20010101145A (en) | 2001-11-14 |
AU7599300A (en) | 2001-04-23 |
TW513696B (en) | 2002-12-11 |
EP1149380A1 (en) | 2001-10-31 |
JP2003511813A (en) | 2003-03-25 |
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