Browse Prior Art Database

An efficient buffer handling method for HDD write reordering

IP.com Disclosure Number: IPCOM000013810D
Original Publication Date: 2001-Mar-01
Included in the Prior Art Database: 2003-Jun-18
Document File: 3 page(s) / 62K

Publishing Venue

IBM

Abstract

Disclosed is a method to improve the hard disk (HDD) performance by using a new buffer handling method for Write Reordering Operation. The traditional way was to order write commands efficiently by sorting write commands in ascending order by LBA. The data of the write commands were stored at sector buffer in order of early coming. The oldest write command has to be written to make free space at sector buffer. It is needed to receive new write commands. Reordering by new way is to write the oldest write command early as possible. A relative write commands such as SEQUENTIAL, SKIP WRITE are called a element. The efficient reordering way is sorting by element. The oldest write command is pointed by firstq_ptr. Following traditional sequence is reordering by the traditional way. On the following new sequence, the element 4 which has the oldest write command will be written first. This new way makes free space at sector buffer efficiently.

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An efficient buffer handling method for HDD write reordering

Disclosed is a method to improve the hard disk (HDD) performance
by using a new buffer handling method for Write Reordering
Operation.

The traditional way was to order write commands efficiently by
sorting write commands in ascending order by LBA.

The data of the write commands were stored at sector buffer in
order of early coming. The oldest write command has to be written
to make free space at sector buffer. It is needed to receive new
write commands. Reordering by new way is to write the oldest
write command early as possible.

A relative write commands such as SEQUENTIAL, SKIP WRITE are
called a element. The efficient reordering way is sorting by
element. The oldest write command is pointed by firstq_ptr.
Following traditional sequence is reordering by the traditional
way. On the following new sequence, the element 4 which has the
oldest write command will be written first. This new way makes
free space at sector buffer efficiently.

.

1

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(Traditional Sequence)

The flow chart is as follows:
exe_ptr means the write command of next execution.
cmdq_ptr means last command of cached write commands.

(N ew sequence)

elem ent 4 includes firstq_ptr

elem ent 1

elem ent 2

elem ent 2

elem ent 3

elem ent 3

elem ent 4 includes firstq_ptr

elem ent 5

elem ent 5

elem ent 1

2

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START

exe_ptr == firstq_ptr

if the start point of firstq_ptr's element...