Rui Miguel Feio

Frames, Pages and Slots

29th October 2010 Rui Miguel Feio

When a program is selected for execution, the system brings it into virtual storage, divides it into pages of 4 kilobytes (4K), and transfers the pages into real storage for execution. To the programmer, the entire program appears to occupy contiguous space in storage at all times. Actually, not all […]

The IEAPAKxx (LPA Pack List) PARMLIB member

29th October 2010 Rui Miguel Feio

IEAPAKxx can be found in the PARMLIB and contains groups of names of modules in the LPALST concatenation that are executed together or in sequence. IEAPAKxx is used only during a “cold” start (CLPA specified), when the PLPA is loaded from the LPALST concatenation. The system uses the specified IEAPAKxx […]

Virtual Storage

28th October 2010 Rui Miguel Feio

Virtual Storage means that each running program can assume it has access to all of the storage defined by the architecture’s addressing scheme. The only limit is the number of bits in a storage address. This ability to use a large number of storage locations is important because a program […]

Physical Storage

28th October 2010 Rui Miguel Feio

Conceptually, mainframes and all other computers have two types of physical storage: – The physical storage located on the mainframe processor itself. This is called processor storage or real storage; think of it as memory for the mainframe. – The physical storage external to the mainframe, including storage on direct […]

Control Blocks

27th October 2010 Rui Miguel Feio

As instructions execute the work of a computer system, they keep track of this work in storage areas known as control blocks. Generally speaking, there are four types of z/OS control blocks: – System-related control blocks – Resource-related control blocks – Job-related control blocks – Task-related control blocks Each system-related […]