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Browse Prior Art Database

Write Encoding Delay Reduction Method

IP.com Disclosure Number: IPCOM000116350D
Original Publication Date: 1995-Sep-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 63K

Publishing Venue

IBM

Related People

Yasuda, T: AUTHOR

Abstract

Disclosed is a method for reduction of channel Write Encoding Delay (WED). Programmable timer masks the data until expected number of patterns come to pre-coding circuit. The pre-coding circuit can output correct sync pattern as soon as write operation is requested. The amount of reduced WED is equivalent to the time during which the data transfer from primary input to the pre-coding circuit.

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This is the abbreviated version, containing approximately 62% of the total text.

Write Encoding Delay Reduction Method

      Disclosed is a method for reduction of channel Write Encoding
Delay (WED).  Programmable timer masks the data until expected number
of patterns come to pre-coding circuit.  The pre-coding circuit can
output correct sync pattern as soon as write operation is requested.
The amount of reduced WED is equivalent to the time during which the
data transfer from primary input to the pre-coding circuit.

      The Hard Disk Controller (HDC) writes sync pattern at the
beginning of every data sector for data synchronization at read
operation.  The HDC usually gives channel several bytes with all '1's
as the sync pattern.  Inside the channel, this pattern doesn't change
before the pre-coding circuit.

      Fig. 1 shows proposed data write process in chart.  Each Pi
(i varies from 0 to n-1) indicates functional unit and each DPi
(i varies from k to n-1) indicates delay cycle unit for corresponding
Pi unit respectively.  DPi unit makes delay of Write Gate for each Pi
unit so that garbage data can't be sent as Write Current Data at the
beginning of write operation.  Pk expresses the pre-coding circuit.
The programmable timer in the Fig. 1 and Gate(A) mask the input data
of the Pk during sync pattern.  This circuit forces the Pk input to
'1' as soon as Write Gate is activated.  After the Programmable Timer
counts up appropriate count, it stops masking and the input data from
Write Data Input goes into the Pk unit without mas...