公开(公告)号：JPH11191267A

公开(公告)日：1999-07-13

申请号：JP11631398

申请日：1998-04-27

Applicant: IBM

Inventor： BRADY JAMES THOMAS

IPC: G11B20/10 ,  G06F3/06 ,  G06F12/00 ,  G11B20/00

Abstract: PROBLEM TO BE SOLVED: To provide an improved memory space allotting device for compressed data. SOLUTION: This device allots a disk memory space for storing a compressed record, enable storing successively compressed record at a physical position on a disk 22 memory space. Such high precision is guaranteed that a record already updated for compression is stored in a physical position already allotted during processing succeeding records, and the device has interchangeability with RAID formation. A disk space allotting procedure 20 used for this method comprises a step by which a record is compressed, a step by which a compressibility (CR) value and the maximum run-length(RL) of the same data segment being continued in a non-compression record are discriminated, and a step by which a CCR value is used for allotting a memory space for a compressed record when a CCR value is less than an expected compressibility (ECR), such as a step by which correction compressibility (CCR) is discriminated by repeating compression of a record without RL of the same data segment being included in a record and continued.

公开(公告)号：DE69127229T2

公开(公告)日：1998-02-12

申请号：DE69127229

申请日：1991-05-20

Applicant: IBM

Inventor： BRADY JAMES THOMAS ,  CINTRON RUTH ENID ,  GOLDSTEIN STEPHEN ,  JU JEAN HO-MING WANG ,  MENON JAISHANKAR MOOTHEDATH

IPC: G06F3/06 ,  G06F11/10 ,  G06F13/42 ,  G11B20/10 ,  G11B20/18

Abstract: Described is a method and means for managing access to a logical track of KN blocks of which K are parity blocks. The KN blocks are distributed and stored in an array of N DASDs having K blocks per physical track per DASD. The array includes control means for securing synchronous access to selectable ones of the DASDs responsive to each access request. The method involves (a) formatting the blocks onto the array using a row major order modulus as the metric for balancing the data rate and concurrency (the number of DASDs bound per access) and (b) executing the random sequences of large and small access requests over array.

公开(公告)号：DE69127229D1

公开(公告)日：1997-09-18

申请号：DE69127229

申请日：1991-05-20

Applicant: IBM

Inventor： BRADY JAMES THOMAS ,  CINTRON RUTH ENID ,  GOLDSTEIN STEPHEN ,  JU JEAN HO-MING WANG ,  MENON JAISHANKAR MOOTHEDATH

IPC: G06F3/06 ,  G06F11/10 ,  G06F13/42 ,  G11B20/10 ,  G11B20/18

Abstract: Described is a method and means for managing access to a logical track of KN blocks of which K are parity blocks. The KN blocks are distributed and stored in an array of N DASDs having K blocks per physical track per DASD. The array includes control means for securing synchronous access to selectable ones of the DASDs responsive to each access request. The method involves (a) formatting the blocks onto the array using a row major order modulus as the metric for balancing the data rate and concurrency (the number of DASDs bound per access) and (b) executing the random sequences of large and small access requests over array.

公开(公告)号：SG60155A1

公开(公告)日：1999-02-22

申请号：SG1997004102

申请日：1997-11-20

Applicant: IBM

Inventor： BENHASE MICHAEL T ,  BRADY JAMES THOMAS ,  FINNEY DAMON W ,  HARTUNG MICHAEL H ,  KO MICHAEL ANTHONY ,  LANG DONALD J ,  MENON JAISHANKAR MOOTHEDATH

IPC: G06F3/06 ,  G06F13/38 ,  G06F12/02

Abstract: A method enables a host processor, which employs variable length (VL) records, to communicate with disk storage which employs fixed length (FL) sectors for storage of the VL records. The method comprises the steps of: a) deriving a first control data structure for an update VL record, the first control data structure including information describing segments of the update VL record; b) determining a disk track that includes a FL sector wherein am old VL record commences that corresponds to the update VL record; c) reading each FL sector in the disk track and creating a control data structure which includes information describing each VL record stored in the disk track; d) substituting in a control data structure for the old VL record that corresponds to the update VL record, information regarding update data from the first control data structure; e) recording in the disk track, data indicated by each control data structure determined in steps c) and d); and f) if the old VL record ends at other than a sector break of a FL sector, reblocking VL records into FL sectors which are recorded thereafter on the disk track. The invention also enables a read action to be accomplished in one rotation of a disk even though it commences at a FL sector that is not at the beginning of a VL record to be accessed.

公开(公告)号：DE69606790D1

公开(公告)日：2000-04-06

申请号：DE69606790

申请日：1996-04-04

Applicant: IBM

Inventor： BRADY JAMES THOMAS ,  DUYANOVICH LINDA MARIE ,  KLOTS BORIS

IPC: H04N5/78 ,  G09G5/00 ,  H04N5/91 ,  H04N7/173

公开(公告)号：SG67500A1

公开(公告)日：1999-09-21

申请号：SG1998001006

申请日：1998-05-04

Applicant: IBM

Inventor： BRADY JAMES THOMAS

IPC: G11B20/10 ,  G06F3/06 ,  G06F12/00 ,  G11B20/00 ,  G06F12/02

Abstract: A system and method allocates disk memory space for storage of compressed records and enables the compressed records to be stored in sequential physical positions on the disk memory space. The method and apparatus further assures a substantial likelihood that compressed, updated records will fit in the originally allocated physical positions during subsequent processing. The method comprises: compressing a record; determining a compression ratio (CR) value and a maximum run length (RL) of contiguous identical data segments in the uncompressed record; determining a corrected compression ratio (CCR) by repeating compression of the record without the RL of contiguous identical data segments included in the record; and if the CCR value is less than a historically experienced record compression ratio, employing the CCR value to allocate memory space for the compressed record. If CCR value equals or exceeds the ECR value, the ECR value is utilized to allocate memory space for the record.

公开(公告)号：DE69606790T2

公开(公告)日：2000-09-07

申请号：DE69606790

申请日：1996-04-04

Applicant: IBM

Inventor： BRADY JAMES THOMAS ,  DUYANOVICH LINDA MARIE ,  KLOTS BORIS

IPC: H04N5/78 ,  G09G5/00 ,  H04N5/91 ,  H04N7/173

公开(公告)号：CA2042872C

公开(公告)日：1995-08-15

申请号：CA2042872

申请日：1991-05-17

Applicant: IBM

Inventor： BRADY JAMES THOMAS ,  CINTRON RUTH ENID ,  GOLDSTEIN STEPHEN ,  JU JEAN HO-MING WANG ,  MENON JAISHANKAR MOOTHEDATH

IPC: G06F3/06 ,  G06F11/10 ,  G06F13/42 ,  G11B20/10 ,  G11B20/18 ,  G06F13/40

Abstract: A method and means for managing access to a logical track of KN blocks of which K are parity blocks. The KN blocks are distributed and stored in an array of N DASDs having K blocks per physical track per DASD. The array includes control means for securing synchronous access to selectable ones of the DASDs responsive to each access request. The method involves (a) formatting the blocks onto the array using a row major order modulus as the metric for balancing the data rate and concurrency (the number of DASDs bound per access) and (b) executing the random sequences of large and small access requests over the array.