Eric A Christensen

Address:

8006 S Farmbelt Dr, Tucson, AZ 85756

Phone:

(520)3004288

VIN:

1J4BA3H17AL192323

Make:

JEEP

Model:

WRANGLER UNLIMITED

Year:

2010

US Patent:

7139142, Nov 21, 2006

Filed:

Oct 29, 2004

Appl. No.:

10/977285

Inventors:

David Berman - San Jose CA, US
Eric Rolf Christensen - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 5/09
G11B 20/10

US Classification:

360 39, 360 48, 360 7712, 360 41

Abstract:

A signal sampler digitally samples magnetic signals detected by read head(s) of a magnetic tape drive, and a signal quality system extracts from the digital samples of a format required signal of the magnetic signals, such as a data set separator pattern, an estimated amplitude of write equalization transitions of the format required signal; and compares the extracted estimated amplitude to acceptable amplitude.

US Patent:

7719782, May 18, 2010

Filed:

Jan 7, 2009

Appl. No.:

12/349661

Inventors:

Allen Keith Bates - Tucson AZ, US
Shawn Owen Brume - Tucson AZ, US
Nhan Xuan Bui - Tucson AZ, US
Joel Hsien-Li Chen - Tucson AZ, US
Eric Rolf Christensen - Tucson AZ, US
Roger Javier Justo - Tucson AZ, US
Daniel James Winarski - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 15/20

US Classification:

360 69

Abstract:

Handling a magnetic tape cartridge comprises the steps of reading cartridge mount information from the cartridge memory; determining from the cartridge mount information whether the present mount is the first mount of the magnetic tape cartridge; and if so, fast forward and rewind the magnetic tape of the magnetic tape cartridge, e. g. , the fast forward is to end of tape (EOT) and the rewind is to beginning of tape (BOT). Alternatively, if the cartridge mount information indicates the present mount is the first mount of the magnetic tape cartridge; monitoring input/output with respect to the magnetic tape cartridge for write errors during the mount; determining whether the number of monitored write errors meets a predetermined threshold; and if so, fast forward and rewind the magnetic tape of the magnetic tape cartridge.

US Patent:

7870427, Jan 11, 2011

Filed:

Aug 10, 2007

Appl. No.:

11/837475

Inventors:

Allen Keith Bates - Tucson AZ, US
Eric Rolf Christensen - Tucson AZ, US
Shinobu Wada - Tokyo, JP
Daniel James Winarski - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 11/00

US Classification:

714 27

Abstract:

Provided are a method, system, and article of manufacture for accessing removable storage management services to obtain replacement instructions indicating whether to replace removable storage. Replacement information indicating whether to replace at least one of a plurality of managed removable storages is obtained by interfacing with a service computer over a network. Read/write error information for the at least one removable storage is gathered and transmitted to the service computer. Replacement instructions indicating whether to replace the at least one removable storage are received from the service computer.

US Patent:

7913117, Mar 22, 2011

Filed:

Aug 10, 2007

Appl. No.:

11/837473

Inventors:

Allen Keith Bates - Tucson AZ, US
Eric Rolf Christensen - Tucson AZ, US
Shinobu Wada - Tokyo, JP
Daniel James Winarski - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 11/00

US Classification:

714 27, 714 42

Abstract:

Provided are a method, system, and article of manufacture for providing removable storage management services using removable storage error information. Read/write error information is obtained for at least one removable storage by interfacing with the removable storage manager. The obtained read/write error information for the at least one removable storage is processed to determine read/write error rates for the at least one removable storage. A determination is made as to whether the determined read/write error rates for the at least one removable storage exceed at least one read/write error threshold. At least one message is sent to the removable storage manager to replace the at least one removable storage having read/write error rates that exceed the at least one read/write error threshold.

US Patent:

8094402, Jan 10, 2012

Filed:

Jan 12, 2010

Appl. No.:

12/686302

Inventors:

Nhan X. Bui - Tucson AZ, US
Edwin R. Childers - Tucson AZ, US
Eric R. Christensen - Tucson AZ, US
Reed A. Hancock - Tucson AZ, US
Diana J. Hellman - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 17/00
G11B 5/584
G11B 20/20

US Classification:

360 71, 360 76, 360 7712, 2423346

Abstract:

Magnetic tape devices encounter read and/or write errors when the tape is not being passed across the head with the proper tension and/or skew angle. According to one embodiment, a system which corrects for these problems comprises a head having an array of at least one of readers and writers, a drive mechanism for passing a magnetic recording tape over the head, a skew-inducing mechanism coupled to the head for adjusting a skew angle of a longitudinal axis of the array relative to a direction normal to a direction of tape travel over the head, and a controller in communication with the head. The system also determines a tape dimensional stability state of the tape and adjust the skew angle away from normal to the direction of tape travel and lowers a tension of the tape across the head if the tape dimensional stability state is in a contracted state.

US Patent:

8111473, Feb 7, 2012

Filed:

Aug 28, 2009

Appl. No.:

12/550319

Inventors:

Eric Rolf Christensen - Tucson AZ, US
W. Stanley Czarnecki - San Jose CA, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 27/36

US Classification:

360 31

Abstract:

A method of evaluating the performance of a magnetic recording system, comprising measuring a first set of finite impulse response filter tap values at time t, measuring a second set of finite impulse response filter tap values are measured at time t, where time t is subsequent to time t, and calculating an actual loss parameter using the first set of tap values and the second set of tap values. The method then compares the actual loss parameter with a total effective loss threshold.

US Patent:

8132050, Mar 6, 2012

Filed:

Jan 27, 2011

Appl. No.:

13/015436

Inventors:

Allen Keith Bates - Tucson AZ, US
Eric Rolf Christensen - Tucson AZ, US
Shinobu Wada - Tokyo, JP
Daniel James Winarski - Tucson AZ, US

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G06F 11/00

US Classification:

714 27

Abstract:

Provided are a method, system, and article of manufacture for providing removable storage management services using removable storage error information. Read/write error information is obtained for at least one removable storage by interfacing with the removable storage manager. The obtained read/write error information for the at least one removable storage is processed to determine read/write error rates for the at least one removable storage. A determination is made as to whether the determined read/write error rates for the at least one removable storage exceed at least one read/write error threshold. At least one message is sent to the removable storage manager to replace the at least one removable storage having read/write error rates that exceed the at least one read/write error threshold.

US Patent:

8605380, Dec 10, 2013

Filed:

Jul 17, 2012

Appl. No.:

13/550603

Inventors:

Eric Rolf Christensen - Tucson AZ, US
Ernest Stewart Gale - Tucson AZ, US
Robert Allen Hutchins - Tucson AZ, US
Sedat Oelcer - Kilchberg, CH

Assignee:

International Business Machines Corporation - Armonk NY

International Classification:

G11B 5/035

US Classification:

360 65

Abstract:

A method for selecting which tap coefficients of a programmable finite-impulse-response (FIR) equalizer to fix includes performing an initial calibration to determine an initial value for each tap coefficient of a FIR equalizer. Using these initial values, a “total” FIR equalizer is determined which sets the tap coefficients to their initial values. The method further determines multiple sets of tap coefficients that may potentially be fixed in the FIR equalizer. For each set of tap coefficients that may potentially be fixed, the method determines a “fixed” FIR equalizer that sets the tap coefficients in the set to their initial values and other tap coefficients to zero. The method then determines a phase-difference energy between the “total” FIR equalizer and the “fixed” FIR equalizer for each set of tap coefficients that may potentially be fixed. The set of tap coefficients associated with the lowest phase-difference energy are then fixed.