Prafulla B Reddy

US Patent:

8448045, May 21, 2013

Filed:

May 26, 2011

Appl. No.:

13/116882

Inventors:

Prafulla Bollampalli Reddy - Longmont CO, US
Peter Igorevich Vasiliev - Longmont CO, US
Hui Su - Longmont CO, US
Timothy Richard Feldman - Louisville CO, US
Mary Elizabeth Dunn - Denver CO, US
James Joseph Touchton - Boulder CO, US
Bernardo Rub - Sudbury MA, US

Assignee:

Seagate Technology LLC - Cupertino CA

International Classification:

G11C 29/00

US Classification:

714764, 714805

Abstract:

Values are grouped into a first set of groupings of values. Based on inner codes, the number of groupings in the first set of groupings that have at least one erroneous value is determined. If the number of groupings in the first set of groupings that have an erroneous value is fewer than a maximum number of groupings that can be corrected by outer codes, a seek operation is begun. During the seek operation, the outer codes are used to detect and correct the erroneous values that were produced during the reading of values. In other aspects, a parity section for a data section of a data storage device is dirtied before writing any data to the data section such that if writing to the data section is interrupted, the parity section will indicate that it should not be used to correct data read from the data section.

US Patent:

20100161917, Jun 24, 2010

Filed:

Dec 23, 2008

Appl. No.:

12/342886

Inventors:

Prafulla Bollampalli Reddy - Longmont CO, US

Assignee:

SEAGATE TECHNOLOGY, LLC - Scotts Valley CA

International Classification:

G06F 12/00

US Classification:

711156, 711E12001

Abstract:

A method includes generating a track description in real-time describing at least a portion of a track of a storage medium. An apparatus includes a dynamic track description generator configured to dynamically generate a track description describing a data wedge of a track on a storage medium, wherein the track description is generated at a time prior to synchronization with the data wedge.

US Patent:

20130007556, Jan 3, 2013

Filed:

Jun 29, 2011

Appl. No.:

13/172457

Inventors:

Ara Patapoutian - Hopkinton MA, US
Hieu V. Nguyen - Superior CO, US
Prafulla Bollampalli Reddy - Longmont CO, US

Assignee:

SEAGATE TECHNOLOGY LLC - Scotts Valley CA

International Classification:

H03M 13/05
H03M 13/29
G06F 11/10
G06F 12/00

US Classification:

714755, 711154, 714752, 711E12001, 714E11032

Abstract:

Presented is a data channel with selectable components, such as encoders or decoders. Also, data having different data signal characteristics can be processed through a data channel based on the data signal characteristics. Further, a data channel may have independent encoding path and an independent decoding path. For example, a first data transmission having first data signal characteristics may be processed via a data channel based on a first selected set of components of the data channel and a second data transmission having second data signal characteristics different than the first data signal characteristics may be processed via the data channel using a second selected set of components in the data channel. The first selected set of components may be different than the second selected set of components, but may share one or more common components.

US Patent:

20130222939, Aug 29, 2013

Filed:

Feb 29, 2012

Appl. No.:

13/408849

Inventors:

Prafulla Bollampalli Reddy - Longmont CO, US
Hui Su - Longmont CO, US
Michelle Elaine Blankenship - Lyons CO, US
Eddie Wai Pun - South San Francisco CA, US
John Marc Wright - Broomfield CO, US
Ara Patapoutian - Hopkinton MA, US
Hieu V. Nguyen - Superior CO, US

Assignee:

SEAGATE TECHNOLOGY LLC - Cupertino CA

International Classification:

G11B 5/09

US Classification:

360 48, G9B 5033

Abstract:

An implementation of a system disclosed herein provides a method of deferring decoding of a data sector received at a read channel of a storage device, in response to determining that a data sector cannot be decoded by a first decoder and storing the data sector for further processing by a second decoder.

US Patent:

57175357, Feb 10, 1998

Filed:

Jan 25, 1995

Appl. No.:

8/377867

Inventors:

Catherine Anne French - Santa Cruz CA
Prafulla Bollampali Reddy - Santa Cruz CA
Jeffrey Alan Miller - Santa Cruz CA

Assignee:

Seagate Technology, Inc. - Scotts Valley CA

International Classification:

G11B 509
G11B 5596

US Classification:

360 53

Abstract:

A magnetic disc storage system includes a rotating magnetic disc and a read/write transducer positioned proximate a recording surface of the magnetic disc for reading and writing information on the recording surface. Data stored on the recording surface is altered based upon the address of the data. During readback, a pseudorandom number generator receives a desired address as a seed input and provides a pseudorandom number output. An XOR gate provides an XOR output in response to the pseudorandom number output and the readback signal from the read/write transducer. An error detection circuit provides a decoded data output and an error flag output in response to the XOR output. An error during readback indicated by the error flag output is indicative of an incorrect address of the readback signal in comparison to the desired address. During a write operation, data is provided to an error detector encoder circuit which provides an encoded data output to an XOR gate. A pseudorandom number generator receives the address of the data as a seed input and provides a pseudorandom number to the XOR gate.

US Patent:

54347190, Jul 18, 1995

Filed:

Mar 18, 1994

Appl. No.:

8/215122

Inventors:

Jeffrey A. Miller - Santa Cruz CA
Mark H. Groo - Scotts Valley CA
Prafulla B. Reddy - Santa Cruz CA
Stanley M. Schekall - Sunnyvale CA

Assignee:

Seagate Technology, Inc. - Scotts Valley CA

International Classification:

G11B 509

US Classification:

360 53

Abstract:

An apparatus for correcting header information includes a transducer for reading and writing encoded information to a magnetic storage medium. A serial/deserializer provides a deserialized output. Header information from the deserializer is stored in a header storage register. The deserialized header information is also provided to a header error correction circuit. The header error correction circuit provides an output indicating location and value of errors in the header memory. This information is used to correct errors in the header memory. The corrected header information is compared with predetermined header information and used to determine whether subsequent data associated with the header should be written to or read from the magnetic storage medium.

US Patent:

58186549, Oct 6, 1998

Filed:

Jun 4, 1997

Appl. No.:

8/869041

Inventors:

Prafulla B. Reddy - Santa Cruz CA
Jimmie R. Shaver - Yukon OK
Sean R. Atsatt - Santa Cruz CA
Mark H. Groo - Boulder Creek CA
Timothy V. Gates - Sunnyvale CA
William K. Weberg - Los Gatos CA

Assignee:

Seagate Technology, Inc. - Scotts Valley CA

International Classification:

G11B 509
G11B 5596

US Classification:

360 53

Abstract:

A memory medium has a plurality of tracks arranged in a plurality of sectors with each track sector having a format which does not include header fields identifying sectors or sector defects or defect management procedures. Track management apparatus identifies the track sector currently confronting a transducer; the track management being based on sector pulses (in the case of a dedicated servo system), or being calculated based on track information, an index pulse and data wedge information from previous wedges (in the case of embedded servo systems), or being derived from a lookup table. To accommodate sector defects, a defect bank contains the identity and type of each defective or spare sector. Defect management apparatus is connected to the defect bank and track management apparatus to indicate when the sector confronting the transducer is a defective or spare sector to halt data transfer to thereby skip the defective sector, or to generate an interrupt signal to the processor to transfer data between the processor and an alternate sector.

US Patent:

56969317, Dec 9, 1997

Filed:

Sep 9, 1994

Appl. No.:

8/303415

Inventors:

Marvin Mang-Yin Lum - San Jose CA
Don Michael Robinson - San Jose CA
Prafulla Bollampali Reddy - Santa Cruz CA
Kathleen Anne Duncan - Santa Cruz CA

Assignee:

Seagate Technology, Inc. - Scotts Valley CA

International Classification:

G06F 1208

US Classification:

395440

Abstract:

A disc controller services a host "read" command, without intervention by the disc controller's microcontroller, if the requested data is found in the disc controller's cache. The disc controller stores at least one cache entry. Each cache entry includes an address, a logical Bit, a valid Bit and a set of four buffer parameters: upper limit address, base address, pointer to the sector count and sector count. Each host command is decoded by the disc controller, and if the command is a "read" command the address in the cache entry is compared against the address in the host command. If the addresses match and the cache entry address is marked as being valid by its Valid bit, a "cache hit" signal is generated and the disc controller starts transferring the data requested by the host without waiting for the disc controller's microprocessor to process the host command. In particular, a sequencer and data transfer circuitry automatically generate a host interrupt request signal and transfer to the host at least a subset of the requested set of data blocks specified by each read command when a cache hit signal is generated. The disc controller includes circuitry for updating the information stored in the cache entry so that said updated information stored in the cache entry identifies data blocks in the cache sequentially subsequent to those data blocks transferred to the host.