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Virtual Storage Access Method (VSAM) [1] is an IBM direct-access storage device (DASD) file storage access method, first used in the OS/VS1, OS/VS2 Release 1 (SVS) and Release 2 (MVS) operating systems, later used throughout the Multiple Virtual Storage (MVS) architecture and now in z/OS.
IDCAMS ("Access Method Services") generates and modifies Virtual Storage Access Method (VSAM) and Non-VSAM datasets. IDCAMS was introduced along with VSAM in OS/VS; the "Access Method" reference derives from the initial "VSAM replaces all other access methods" mindset of OS/VS. IDCAMS probably has the most functionality of all the utility ...
Job Control Language (JCL) is a scripting language used on IBM mainframe operating systems to instruct the system on how to run a batch job or start a subsystem. [1] The purpose of JCL is to say which programs to run, using which files or devices [2] for input or output, and at times to also indicate under what conditions to skip a step.
JCL is used to define jobs to both JES2 and JES3, but small changes usually need to be made to the JCL to get a job written for one JES to run on the other. A common issue was that JES3 checked that all datasets listed in the JCL existed before execution or that there was a prior step where the dataset was defined as NEW,CATLG.
An entry-sequenced data set (ESDS) is a type of data set used by IBM's VSAM computer data storage system. [1]: 5 Records are accessed based on their sequential order, that is, the order in which they were written to the file; which means that accessing a particular record involves searching all the records sequentially until it is located, or by using a relative physical address (Relative byte ...
Apache Commons Logging (previously known as Jakarta Commons Logging or JCL) is a Java-based logging utility and a programming model for logging and for other toolkits. It provides APIs , log implementations, and wrapper implementations over some other tools.
Full ACID transaction management systems are provided by some ISAM client–server implementations. [5] These are the basic concepts behind a database management system (DBMS), which is a client layer over the underlying data store. ISAM was replaced at IBM with a methodology called VSAM (virtual storage access method).
By design, programs written for MVS run on z/OS without modification. At first IBM described MVS as simply a new release of OS/VS2 , but it is, in fact a major rewrite. OS/VS2 release 1 is an upgrade of OS/360 MVT that retained most of the original code and, like MVT, is mainly written in assembly language .