z/OS Systems Programming Basics Flashcards
What is virtual storage
A technique that makes programs believe all required program instructions are residing in real storage.
How is virtual storage accomplished?
Through using auxiliary storage. Older data is moved to auxiliary storage until needed.
Tasks require a given amount of memory, how does virtual memory handle multiple tasks whose tasks require more real storage than is available?
By queueing in virtual storage, then swapping to real when the task is active
Swapping in and out of auxiliary storage is taxing. How does IBM handle this process?
Through IBM’s System Resource Manager (SRM)
How does IBM’s System Resource Manager (SRM) ensure page swapping is not taxing?
Through logical swapping by keeping the address space in real storage, while making it appear it has been swapped out (keeping it in real storage)
What is done the real and aux storage when a task is completed?
It is released for other tasks
Virtual storage is divided in what?
Pages
What is a page in virtual storage?
A fixed-length piece of virtual storage, usually 4 KB in size.
What is the typical size of a virtual storage page?
4 KB
What is a frame?
A fixed-length piece of central storage (memory), usually 4 KB in size.
What is a slot?
Auxiliary storage is divided into 4 KB (or 1 MB or 2GB) units called
What is a page?
A fixed-length piece of virtual storage, usually 4 KB in size.
Addressable space that appears as real memory
Virtual Storage
Active physical system memory
Real Storage
Storage that is not central storage, such as flash storage and DASD
Auxiliary Storage
Name that acronym
SQA
System Queue Area
System Queue Area
Contains system tables that are critical to the entire system
Nucleus
Contains operating system control programs
Name that acronym
PLPA
Pageable Link Pack Area
Pageable Link Pack Area
Stores many of the z/OS modules
Name that acronym
FLPA
Fixed Link Pack Area
Fixed Link Pack Area (FLPA)
Also stores z/OS modules
Name that acronym
MLPA
Modified Link Pack Area
Modified Link Pack Area
Stores z/OS modules for the duration of the IPL only
Name that acronym
CSA
Common Service Area
Common Service Area
Primarily used for inter-address space communication
Name that acronym
LS
When is auxiliary storage released?
When the task is completed
In which area of virtual storage are the PLPA and the CSA?
Common
If MVS ran out of storage in the SQA, where would it dynamically allocate more SQA storage?
CSA
