Rui Miguel Feio

Dynamic Address Translation (DAT)

27th October 2010 Rui Miguel Feio

Dynamic Address Translation, or DAT, is the process of translating a virtual address during a storage reference into the corresponding real address. If the virtual address is already in real storage, the DAT process may be accelerated through the use of a translation lookaside buffer; if the virtual address is […]

Interrupt Processing

27th October 2010 Rui Miguel Feio

An interrupt is an event that alters the sequence in which the processor executes instructions. An interrupt might be planned (specifically requested by the currently running program) or unplanned (caused by an event that might or might not be related to the currently running program). z/OS uses six types of […]

Generation Data Group (GDG)

18th September 2010 Rui Miguel Feio

GDG is a collection of historically related non-VSAM data sets that are arranged in chronological order. Each data set within a GDG is called a generation data set (GDS) or generation. Within a GDG, the generations can have like or unlike DCB attributes and data set organizations. If the attributes […]

JCL most common operands

9th September 2010 Rui Miguel Feio

1. JOB Statement REGION= Requests specific memory resources to be allocated to the Job NOTIFY= User to be notified at job completion USER= Userid to assume authority to the Job TIME= Limits the amount of time a program can run TYPRUN= Delays or holds the Job from running CLASS= Directs […]

Virtual Storage Access Method (VSAM)

9th September 2010 Rui Miguel Feio

VSAM applies to both a data set type and the access method used to manage various user data types. VSAM data sets are held on direct access storage devices (DASD) auxiliary storage. VSAM divides its data set storage into control areas (CA), which are further divided into control intervals (CI). […]