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A method how to accelerate "Data Access Redirectors". Disclosure Number: IPCOM000015728D
Original Publication Date: 2002-Jul-12
Included in the Prior Art Database: 2003-Jun-21

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In known computer systems, applications (programs) are using data on non volatile data storage, here called disk. For accessing data on these disks, so called “Data Access Methods” are used. Programs are written (compiled) with certain access method characteristics and cannot access data on disks which are organized for different access methods. Another known approach is used by the IBM VSE/ESA ® Data Access Redirector (SYSTEM AND METHOD FOR REDIRECTION OF HOST DATA ACCESS TO MULTIPLE NON-HOST FILE SYSTEMS OR DATA STORES ® ). It is able to access data on different file systems (data bases) without changing existing programs, which where written for certain access methods. The Data Access Redirector can either access data on different file systems in parallel to the existing original data on disk, or can access data on different file systems and skip the access to the original data on disk. This (the second) usage may be the preferred status after data and file system migration. The advantage is to have data on modern file systems, but to use existing (not changeable) programs to access those data. (cf. Fig. 1) A drawback of the system is that the original data sets have to be available all the time as model for the organization of the data records and file types. If no data access to the original data set could be done, at least empty data sets and data set descriptions (e.g. in real catalogs) must be available.