DASD cache block staging
Method and apparatus for grouping asynchronous recording operations
Sequentially processing data in a cached data storage system
Managing high speed slow access channel to slow speed cyclic system data transfer
Multilevel, hierarchical, dynamically mapped data storage subsystem
Data storage system for providing redundant copies of data on different disk drives
Logical data tracks extending among a plurality of zones of physical tracks of one or more disk devices
System and method for disk mapping and data retrieval
Method for operating a cached peripheral data storage subsystem including a step of subsetting the data transfer into subsets of data records
Disk rotational position controls for channel operations in a cached peripheral subsystem
ApplicationNo. 271335 filed on 07/06/1994
US Classes:703/23, EMULATION360/48, Data in specific format711/100STORAGE ACCESSING AND CONTROL
ExaminersPrimary: Teska, Kevin J.
Assistant: Frejd, Russell W.
Attorney, Agent or Firm
International ClassG11B 005/09
AbstractA method and apparatus for updating CKD data stored on fixed block media, and more particularly to creating Track Format Descriptors which are data structures loaded into electronic memory to enable fast writing of data without loading an entire CKD emulated track of data into memory. A control unit is provided with logic to provide Track Format Descriptors which describe the format of the track without the need for the data content of the track to be resident in cache, or electronic memory. An emulated CKD volume corresponds to a volume of data stored on a multi-disk device. Each track on a volume is represented by a Track Format Descriptor. The Track Format Descriptor forms a representation of the format according to the following general procedure. If the format is a predefined format, in other words one that is already known by the control unit then a track form descriptor is formed to represent the format. If the format is easily discernible, it is said to be "well behaved". "Well behaved" formats are ones in which either each record has the same field length, there is no key field, or record numbers start at one and increment by one. A Track Format Descriptor is formed by predicting the format of these so called "well behaved" formats. If the format is not "well behaved" and the format has not been predefined, then the entire data track must be loaded into cache memory, before a fast write operation is performed. The Track Format Descriptor serves as an index to other information data structures which are loaded into memory when required by logic in the control unit.
Field of SearchData in specific format