Browse Prior Art Database

Power Save Control for Disk Read/Write Electronic Circuit

IP.com Disclosure Number: IPCOM000119285D
Original Publication Date: 1991-Jan-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 61K

Publishing Venue

IBM

Related People

Numata, T: AUTHOR [+3]

Abstract

Disclosed is a technique to decrease a power consumption for a small hard disk system by cutting out a power for Read/Write (R/W) electronic circuit when it is not used. This technique does not require any extra burden for a microprocessor of the disk system.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 66% of the total text.

Power Save Control for Disk Read/Write Electronic Circuit

      Disclosed is a technique to decrease a power consumption
for a small hard disk system by cutting out a power for Read/Write
(R/W) electronic circuit when it is not used. This technique does not
require any extra burden for a microprocessor of the disk system.

      The disk Read/Write electronic circuit, which includes Head
Preamplifier, Pulse Detector, Data Synchronizer and Disk Code
Encoder, are required to be powered on only while data is read from
or written to a disk by a host system. Thus, it is widely used to
switch the R/W electronic circuit off during other times, such as
seeking, head switching or idle time.  The disclosed technique uses
an internal signal of Hard Disk Controller (HDC) IC.  Fig. 1 shows a
circuit to generate that internal signal of HDC, which is called
'+SEQSTART'.  When some Read or Write command is executed in HDC,
+BUSY1 signal goes active and then +SEQSTART goes active at the next
positive edge of +SECTOR, which indicates a physical starting
position of a data block.  This +SEQSTART is cleared by -CMDFAIL,
-CMDRST or -CMDCOMP signal.  -CMDFAIL goes active when HDC found some
error on disk read data, - CMDRST goes active when the ID read is not
a target ID, and -CMDCOMP goes active when a sector's sequence have
completed without error.  As a result of that, +SEQSTART is active
when the disk data is actually reading or writing.  This is the only
information available...