Claims
- 1. A method for recording data at variable speeds onto a magnetic tape that is being transported across a rotating drum at a current tape transport speed, said rotating drum having a recording head disposed thereon to pass over said tape once per single rotation of said drum, said data being received from a host system and temporarily stored in a data buffer, said method comprising:
monitoring a current buffer level of said data buffer, said current buffer level indicating an amount of data currently present in said data buffer; determining a new tape transport speed based on said current buffer level; and adjusting said current tape transport speed to said new tape transport speed; wherein said current tape transport speed and said new tape transport speed are each non-zero.
- 2. A method in accordance with claim 1, comprising:
recording a track onto said magnetic tape at said new tape transport speed.
- 3. A method in accordance with claim 2, wherein:
said recording step comprises:
recording a first set of tracks onto said tape at said current tape transport speed prior to adjusting said current tape transport speed to said new tape transport speed; and recording a second set of tracks onto said tape after said current tape transport speed has been adjusted to said new tape transport speed.
- 4. A method in accordance with claim 3, wherein:
said first set of tracks comprises a first data track, said first data track comprising a first set of said data in said data buffer that has been formatted into said first data track; and said second set of tracks comprises a second data track, said second data track comprising a second set of said data in said data buffer that has been formatted into said second data track.
- 5. A method in accordance with claim 3, wherein:
said first set of tracks comprises a first predetermined number of dummy tracks; and said second set of tracks comprises a second predetermined number of dummy tracks.
- 6. A method in accordance with claim 3, wherein:
said first set of tracks comprises a first data track followed by a first predetermined number of dummy tracks, said first data track comprising a first set of data in said data buffer that has been formatted into said first data track; and said second set of tracks comprises a second data track followed by a second predetermined number of dummy tracks, said second data track comprising a second set of data in said data buffer that has been formatted into said second data track.
- 7. A method in accordance with claim 1, wherein said new tape transport speed is slower than said current tape transport speed.
- 8. A method in accordance with claim 1, wherein:
said new tape transport speed is faster than said current tape transport speed.
- 9. A method in accordance with claim 2, comprising:
measuring said current tape transport speed; determining whether said current tape transport speed is outside a speed control limit; and if said current tape transport speed is outside said speed control limit, performing the steps of:
setting said new tape transport speed to a speed within said speed control limit; adjusting said current tape transport speed to said new tape transport speed; and re-recording said track onto said magnetic tape at said new tape transport speed.
- 10. A method in accordance with claim 2, comprising:
measuring a track pitch, said track pitch comprising the distance between said recorded track and an immediately-previous previously-recorded track; determining whether said track pitch is outside a track pitch control limit; and if said track pitch is outside said track pitch control limit, performing the steps of:
setting said new tape transport speed to a speed that will place a next measured track pitch within said track pitch control limit; adjusting said current tape transport speed to said new tape transport speed; and re-recording said track onto said magnetic tape at said new tape transport speed.
- 11. A method in accordance with claim 1, wherein:
said adjusting step comprises:
commencing said speed adjustment when said rotating drum is positioned such that said recording head is not positioned over said tape; and completing said speed adjustment before said recording head becomes positioned over said tape.
- 12. A method in accordance with claim 2, comprising:
reading back said recorded track at said new tape transport speed immediately after said recorded track is recorded onto said magnetic tape.
- 13. A method in accordance with claim 12, comprising:
re-recording said track if said recorded track is unreadable.
- 14. A method in accordance with claim 1, comprising:
reading a track from said magnetic tape at said new speed.
- 15. A method for recording data at variable speeds onto a magnetic tape that is being transported across a rotating drum at a first tape transport speed, said rotating drum having a recording head disposed thereon to pass over said tape once per single rotation of said drum, said data being received from a host system and temporarily stored in a data buffer, said method comprising:
halting tape transport such that a current tape transport speed is reduced to zero; monitoring a current buffer level of said data buffer, said current buffer level indicating an amount of data currently present in said data buffer; determining a second tape transport speed based on said current buffer level, said second tape transport speed being non-zero; and adjusting said current tape transport speed from zero to said second tape transport speed to commence tape transport.
- 16. A method in accordance with claim 15, comprising:
recording a track onto said magnetic tape at said second tape transport speed.
- 17. A method in accordance with claim 16, wherein:
said recording step comprises:
recording a first set of tracks onto said tape at said first tape transport speed prior to adjusting said current tape transport speed to said second tape transport speed; and recording a second set of tracks onto said tape after said current tape transport speed has been adjusted to said second tape transport speed.
- 18. A method in accordance with claim 17, wherein:
said first set of tracks comprises a first data track, said first data track comprising a first set of said data in said data buffer that has been formatted into said first data track; and said second set of tracks comprises a second data track, said second data track comprising a second set of said data in said data buffer that has been formatted into said second data track.
- 19. A method in accordance with claim 17, wherein:
said first set of tracks comprises a first predetermined number of dummy tracks; and said second set of tracks comprises a second predetermined number of dummy tracks.
- 20. A method in accordance with claim 17, wherein:
said first set of tracks comprises a first data track followed by a first predetermined number of dummy tracks, said first data track comprising a first set of data in said data buffer that has been formatted into said first data track; and said second set of tracks comprises a second data track followed by a second predetermined number of dummy tracks, said second data track comprising a second set of data in said data buffer that has been formatted into said second data track.
- 21. A method in accordance with claim 15, wherein:
said first tape transport speed is identical to said second tape transport speed.
- 22. A method in accordance with claim 15, wherein said second tape transport speed is slower than said first tape transport speed.
- 23. A method in accordance with claim 15, wherein:
said second tape transport speed is faster than said first tape transport speed.
- 24. A method in accordance with claim 16, comprising:
measuring said current tape transport speed; determining whether said current tape transport speed is outside a speed control limit; and if said current tape transport speed is outside said speed control limit, performing the steps of:
setting a third tape transport speed to a speed within said speed control limit; adjusting said current tape transport speed to said third tape transport speed; and re-recording said track onto said magnetic tape at said third tape transport speed.
- 25. A method in accordance with claim 16, comprising:
measuring a track pitch, said track pitch comprising the distance between said recorded track and an immediately-previous previously-recorded track; determining whether said track pitch is outside a track pitch control limit; and if said track pitch is outside said track pitch control limit, performing the steps of:
setting a third tape transport speed to a speed that will place a next measured track pitch within said track pitch control limit; adjusting said current tape transport speed to said third tape transport speed; and re-recording said track onto said magnetic tape at said third tape transport speed.
- 26. A method in accordance with claim 15, wherein:
said adjusting step comprises:
commencing said speed adjustment when said rotating drum is positioned such that said recording head is not positioned over said tape; and completing said speed adjustment before said recording head becomes positioned over said tape.
- 27. A method in accordance with claim 16, comprising:
reading back said recorded track at said second tape transport speed immediately after said recorded track is recorded onto said magnetic tape.
- 28. A method in accordance with claim 26, comprising:
re-recording said track if said recorded track is unreadable.
- 29. A method in accordance with claim 15, comprising:
reading a track from said magnetic tape at said second speed.
- 30. A reel tension controller for a tape transport mechanism, said tape transport mechanism comprising a capstan which controls tape transport, a supply reel and a takeup reel between which a magnetic tape is transported, comprising:
a reel amplifier responsive to a reel amplifier input signal to adjust the tension between said capstan and said supply reel and said takeup reel; a controller responsive to correct tension parameters, a supply reel radius signal, and a takeup reel radius signal, said controller generating said reel amplifier input signal based on said correct tension parameter, said supply reel radius signal and said takeup reel radius signal.
- 31. A method for preventing the recording of a thin track on a magnetic medium by a magnetic tape drive, said magnetic tape drive comprising a tape transport mechanism comprising a supply reel, a takeup reel, a recording head, and a capstan which moves a magnetic tape between said supply reel and said takeup reel in a path across said recording head, said capstan comprising a capstan tachometer which maintains a capstan tach count proportional to a number of revolutions of said capstan that have occurred relative to a beginning-of-tape position of said magnetic tape in said drive, said method comprising the steps of:
determining a reference position of a track based upon a current tape speed; measuring a current position of said track based upon said current tach count of said capstan; determining a current track spacing, said current track spacing comprising the distance between a first track and a second adjacent track; calculating a current track spacing error from said reference position and said current position; and if said current track spacing error is below an acceptable track spacing error threshold:
setting said reference position to said current position; setting said current track spacing error to zero.
- 32. A method in accordance with claim 31, comprising the step of:
repeating each of said steps periodically.
RELATED PATENTS
[0001] The present invention is related to co-pending U.S. patent application entitled “Overscan Helical Scan Head for Non-Tracking Tap Subsystems Reading at up to 1× Speed and Method for Simulation of Same”, invented by Blatchley et al., and having an internal docket number of 9086/106 and a Ser. No. of ______, filed concurrently herewith on Oct. 20, 1998, and co-pending U.S. patent application entitled “Fine Granularity Rewrite Method and Apparatus for Data Storage Device”, invented by Zaczek, and having an internal docket number of 9086/106 and a Ser. No. of ______, filed concurrently herewith on Oct. 20, 1998, and co-pending U.S. patent application entitled “Multi-level Error Detection and Correction Technique for Data Storage Recording Device”, invented by McAuliffe et al., and having an internal docket number of 9086/102 and a Ser. No. of ______, filed concurrently herewith on Oct. 20, 1998, all of which are commonly owned and all of which are hereby incorporated by reference.
Divisions (2)
|
Number |
Date |
Country |
Parent |
09946414 |
Sep 2001 |
US |
Child |
10219434 |
Aug 2002 |
US |
Parent |
09176079 |
Oct 1998 |
US |
Child |
09946414 |
Sep 2001 |
US |