Thursday, August 8, 2019
How Are Program Libraries Concatenated Assignment - 1
How Are Program Libraries Concatenated - Assignment Example Concatenation allows the data sets to be processed in a sequence automatically (Ebbers et al., 2011). Ã - NEW designate that a new data set will be developed. The job has a unique access to the data set while it is running. Additionally, the data set should not exist on the same volume containing the new data, set or be in the system or user catalog (Ebbers et al., 2012). Ã - SHR shows that a data set is already existing and that various concurrent jobs are able to share access and at the same time run. Mainly, all concurrent jobs should specify SHR (Ebbers et al., 2012). Ã DISP=NEW shows that a file is new and does not exist in the system. DISP=OLD is used to show that a file will be overwritten, and hence the old data will disappear and replaced with new data. DISP=MOD implies that a new data is to be added at the end of a file (Ebbers et al., 2012). Ã An indexed VSAM file is used when the data sets are held in control areas (CA) and control intervals (CI). The indexed VSAM file is used when the records are ordered according to a collating sequence of an embedded prime key field. Also, it is used where the order of the records is fixed or where the records are commanded by their relative key. In addition, VSAM files are used to insert new records into a suitable place in a file as well as the records that follow, which are moved to a new location. The VSAM file is used when there is no need for reorganization (Singh, 2011). Ã The advantage of using a VSAM file is that various datasets are accessed efficiently and quickly because of its organization. Another advantage is that records are inserted in an effective way. The disadvantage of VSAM file usage is that the records are deleted from the disk physically rather than being removed logically (Somnath, 2010). Ã - IEBGENER is a utility that copies one sequential data set to another.
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