Apparatus and method for writing data onto rewritable optical media

• US 5,715,424 A
• Filed: 12/11/1996
• Issued: 02/03/1998
• Est. Priority Date: 12/10/1992
• Status: Expired due to Fees

• Current Assignee: MediaTek, Inc.
• Original Assignee: International Business Machines Corporation
• Inventors: Jesionowski, Leonard George, Kulakowski, John Edward, Means, Rodney Jerome
• Primary Examiner(s): Chan, Eddie P.
• Assistant Examiner(s): BRAGDON, REGINALD GLENWOOD
• Application Number:
  US08/763,876
• Time in Patent Office: 419 Days
• Field of Search: 395/440, 395/471, 395/470, 395/182.22
• US Class Current: 714/24
• CPC Class Codes: G06F 12/0866 for peripheral storage systems, e.g. disk cache
• CPC Class Codes: G06F 3/0611 in relation to response time
• CPC Class Codes: G06F 3/0613 in relation to throughput
• CPC Class Codes: G06F 3/0652 Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket
• CPC Class Codes: G06F 3/0655 Vertical data movement, i.e. input-output transfer; data movement between one or more hosts and one or more storage devices
• CPC Class Codes: G06F 3/0677 Optical disk device, e.g. CD-ROM, DVD
• CPC Class Codes: G11B 11/10517 Overwriting or erasing G11B11/10526 takes precedence
• CPC Class Codes: G11B 11/10595 Control of operating function
• CPC Class Codes: G11B 20/1879 Direct read-after-write methods
• CPC Class Codes: G11B 2020/10916 Seeking data on the record carrier for preparing an access to a specific address
• CPC Class Codes: G11B 27/36 Monitoring, i.e. supervising the progress of recording or reproducing for digital recording G11B20/00 and s.gr.; for monitoring, testing or measuring of TV recorders of the type covered by H04N5/76 and subgroups, see H04N17/06
• CPC Class Codes: G11B 7/006 Overwriting G11B7/0065 takes precedence

Abstract

An apparatus and method are provided for amortizing the adverse performance impact of an erase-write-verify process for rewritable optical disks, with its numerous delays, over multiple sectors. A block of data to be written to a sector on a particular track of the disk is transferred from the host to a cache storage device. When a predetermined number of blocks to be written to the track have accumulated in the cache, destaging will occur. Those sectors to which the blocks will be written are erased in a single pass. Then the blocks are written to the erased sectors in the next pass. Verification of the written data, if desired, can be performed in a third pass. Consequently, only two passes per track (or three, if verification is desired) are required to record data from the host to the disk instead of two passes (or three) per block using conventional methods and the seek and latency delays are also reduced. Multiple tracks can be destaged in an order established by a controller. Immediate destaging can occur if an event occurs requiring destaging which would otherwise jeopardize the integrity of the blocks of data retained in the cache.

Claims

1. An apparatus for storing data on a rewritable optical disk in an optical disk drive, comprising:

interface means for receiving blocks of data during multiple write operations from a host device to be written to corresponding sectors of a rewritable optical disk;

memory means coupled to said interface means for accumulating the blocks of data;

means for notifying the host device that a write operation is complete upon receipt of a block of data in said memory means;

processor means for;

indicating that data in each sector of the rewritable optical disk corresponding to each block of data accumulated in said memory means has been superseded, wherein a command from the host device to read selected data which has been accumulated in said memory means is to be satisfied from the block of data accumulated in said memory means;

arranging said blocks of data such that said blocks of data can be destaged to said corresponding sectors in a sequence that minimizes seek times along the rewritable optical disk;

destaging said blocks of data from said memory means to said corresponding sectors when a predetermined threshold has been reached in said memory means by;

erasing data from all of said corresponding sectors during a first single pass of the rewritable optical disk; and

writing data in said blocks from said memory means to said corresponding sectors during a second single pass of the rewritable optical disk; and

indicating that data in each sector of the rewritable optical disk which is destaged from said memory means has been updated, wherein a command from the host device to read selected data which has been accumulated in said memory means can be satisfied from a selected one of the block of data accumulated in said memory means and the data written to the corresponding sector.

2. A rewritable optical disk subsystem, comprising:

an optical drive into which a rewritable optical disk is loadable;

interface means for receiving blocks of data during multiple write operations from a host device to be written to corresponding sectors of a rewritable optical disk;

memory means coupled to said interface means for accumulating the blocks of data;

means for notifying the host device that a write operation is complete upon receipt of a block of data in said memory means;

processor means for;

indicating that data in each sector of the rewritable optical disk corresponding to each block of data accumulated in said memory means has been superseded, wherein a command from the host device to read selected data which has been accumulated in said memory means is to be satisfied from the block of data accumulated in said memory means;

arranging said blocks of data such that said blocks of data can be destaged to said corresponding sectors in a sequence that minimizes seek times along the rewritable optical disk;

destaging said blocks of data from said memory means to said corresponding sectors when a predetermined threshold has been reached in said memory means by;

erasing data from all of said corresponding sectors during a first single pass of the rewritable optical disk; and

writing data in said blocks from said memory means to said corresponding sectors during a second single pass of the rewritable optical disk; and

indicating that data in each sector of the rewritable optical disk which is destaged from said memory means has been updated, wherein a command from the host device to read selected data which has been accumulated in said memory means can be satisfied from a selected one of the block of data accumulated in said memory means and the data written to the corresponding sector.

3. A method for storing data on a rewritable optical disk mounted in an optical disk drive, comprising the steps of:

transferring a block of data, to be written to a rewritable optical disk, from a host device to a memory device;

notifying the host device that a write operation is complete;

indicating that data in a sector of the rewritable optical disk corresponding to the block of data accumulated in the memory device has been superseded, wherein a command from the host device to read the block data is to be satisfied from the block of data accumulated in said memory means and not from the data in the corresponding sector of the rewritable optical disk;

arranging said blocks of data such that said blocks of data can be destaged to said corresponding sectors in a sequence that minimizes seek times along the rewritable optical disk; and

destaging said blocks of data from the memory device to said corresponding sectors of the rewritable optical disk when a predetermined threshold has been reached in the memory device, said destaging step further comprising;

erasing data from a plurality of sectors on the rewritable optical disk during a first single pass of the rewritable optical disk; and

writing data in the predetermined number of blocks from the memory device to the corresponding plurality of sectors during a second single pass of the rewritable optical disk; and

indicating that data in each corresponding sector of the rewritable optical disk which is destaged from the memory device have been updated, wherein a command from the host device to read selected data which has been accumulated in the memory device means can be satisfied from a selected one of the block of data accumulated in the memory device and the data written to the corresponding sector.