Topic
Count key data
About: Count key data is a research topic. Over the lifetime, 12 publications have been published within this topic receiving 336 citations. The topic is also known as: CKD.
Papers
Patent•
18 Jun 1990TL;DR: In this article, the use of a dynamically mapped virtual memory system (100) permits the storage of data so that each data record occupies only the physical space required for the data.
Abstract: The use of a dynamically mapped virtual memory system (100) permits the storage of data so that each data record occupies only the physical space required for the data. Furthermore, the data storage subsystem (100) manages the allocation of physical space on the disk drives (122-125) and does not rely on the file extend defined in the count key data format. Data compaction apparatus is provided to remove the gaps contained in the stream of count key data records received from the host processor (11, 12). A data compression algorithm (203-0) is then used to compress the received data into a compressed format for storage on the disk drives (122-125). It is the compacted, compressed data that is finally stored on the disk drives (122-125). Furthermore, any data record received from the host processor (11, 12) absent data in the user data field therein is simply listed in the virtual memory map as a null field occupying no physical space on the disk drives (122-125). The data storage control (101), through its mapping capability, stores the actual data in the minimum physical space required by overcoming the limitations imposed on large form factor disk drives by the use of count key data format data records. However, the data storage subsystem (100) returns this stored data to the host processor (11, 12) in count key data format through a data record reformatting process once the stored compacted compressed data is staged to the cache memory (113) for access by the host processor (11, 12). The data storage subsystem (100) is operationally independent of the host processor (11, 12), yet performs as if it were a standard operationally dependent large form factor disk subsystem.
166 citations
Patent•
IBM1
TL;DR: In this article, the authors describe a large capacity data storing disk that includes a volume table of contents (VTOC) which identifies allocated ones of data storage tracks and identification of the data contents therein, indications of unallocated data storage track and an indication of which of the storage tracks on the large capacity disk surface are unformatted.
Abstract: A large capacity data storing disk includes a volume table of contents (VTOC) which identifies allocated ones of data storage tracks and identification of the data contents therein, indications of unallocated data storage track and an indication of which of the data storage tracks on the large capacity disk surface are unformatted. The indications may also include indications of unallocated "erased" tracks that do not contain data residuals from previous recordings. Those unallocated tracks having such erased condition in a count key data record format (CKD) require a home address record on each of the formatted tracks. The home address record may include indications of rotational position of defects to be skipped over during the recording and readback operations. A specific embodiment of the invention using a magnetooptic record medium is described.
63 citations
Patent•
IBM1
TL;DR: In this article, an apparatus, system, and method for detecting mismatches in a mirror volume are disclosed for detecting inconsistencies in a record set in the primary and secondary storage systems.
Abstract: An apparatus, system, and method are disclosed for detecting mismatches in a mirror volume. A receive module receives a start indicator from a primary storage system. The start indicator includes a starting location of a first block to be modified on a track in a secondary storage system. The first block corresponds to an identically located first block of a modified record in the primary storage system. The tracks the first blocks on the primary and secondary storage systems each comprise irregular count key data (“CKD”) tracks. A compare module compares the first block location indicated by the start indicator with block locations listed in track metadata. The track metadata describes user records on the irregular CKD tracks of the secondary storage system. An alert module generates an alert in response to the first block not aligning with a beginning block of a record on the secondary storage system.
27 citations
TL;DR: The state of the art file and I/O system design and optimization as it applies to large data processing installations is surveyed and some research results applicable to both current and future system designs are summarized.
22 citations
Patent•
IBM1
TL;DR: In this article, the cache directory control block (CDCB) includes a CDCB synchronization flag for each CKD track in cache memory, indicating a failure of synchronization between CKD tracks and associated meta data.
Abstract: A storage system, method of managing a storage system and program product for managing a storage system. Cache fast write (CFW) modified data may be provided to cache in count-key-data (CKD) tracks with associated meta data. A synchronization flag is included on a storage device with associated meta data for each CKD track stored. The cache directory control block (CDCB) includes a CDCB synchronization flag for each CKD track in cache memory. A mismatch in the synchronization flags from a failure during a transfer to storage indicates a storage device loss of synchronization between an accessed CKD track and stored associated meta data.
21 citations
Performance Metrics
| Year | Papers |
|---|---|
| 2019 | 1 |
| 2013 | 1 |
| 2012 | 1 |
| 2008 | 1 |
| 2006 | 1 |
| 2003 | 1 |