Search results
Results From The WOW.Com Content Network
The Sort/Merge utility is a mainframe program to sort records in a file into a specified order, merge pre-sorted files into a sorted file, or copy selected records. Internally, these utilities use one or more of the standard sorting algorithms , often with proprietary fine-tuned code.
The operation of SORT is directed by control statements, which are largely compatible among various IBM and third-party sort programs. The SORT or MERGE statement defines the sort keys— the fields on which the data is to be sorted or merged. This statement identifies the position, length, and data type of each key.
external sorting algorithm. External sorting is a class of sorting algorithms that can handle massive amounts of data.External sorting is required when the data being sorted do not fit into the main memory of a computing device (usually RAM) and instead they must reside in the slower external memory, usually a disk drive.
In IBM mainframe operating systems, such as OS/360, MVS, z/OS, a Data Control Block (DCB) is a description of a dataset in a program. A DCB is coded in Assembler programs using the DCB macro instruction (which expands into a large number of "define constant" instructions). High level language programmers use library routines containing DCBs.
The end of data statement marks the end of data in the input stream. The format is /*. Any data on the statement following the blank is ignored. The end of job statement marks the end of a job, and may indicate the end of data to be flushed if the job terminates abnormally. The format is /&. Any data on the statement following the blank is ignored.
A polyphase merge sort is a variation of a bottom-up merge sort that sorts a list using an initial uneven distribution of sub-lists (runs), primarily used for external sorting, and is more efficient than an ordinary merge sort when there are fewer than eight external working files (such as a tape drive or a file on a hard drive).
IBM Data Facility Sort (DFSORT) Release 10.0 In addition to replacing part of the device support in the base MVS/SP, DFP replaces the Linkage Editor and several utility programs and service aids. DFP is no longer available as a separate product, but has become part of Data Facility Storage Management Subsystem, under the name DFSMSdfp.
In order to serialize accesses between data records on a loosely coupled system, a practice known as record locking must be used. This means that when one mainframe processor obtains a hold on a record, the mechanism must prevent all other processors from obtaining the same hold and communicate to the requesting processors that they are waiting.