Address Space Storage Workspace

This workspace provides information about the storage allocated to an address space. It contains two table views and two bar charts.

The Address Space Real Storage table view provides information about the real storage allocated to an address space in terms of various types of frame counts and slot counts, as well as the management status of a given address space.

A frame is the basic unit of real and expanded storage. A slot is the basic unit of auxiliary storage. Each frame or slot consists of 4096 bytes of contiguous storage. An address space's pages reside either on frames or in slots. Central Frames are those frames that are online or accessible to the processor or have been varied offline using a z/OS command or by the system itself. Fixed Frames are those pages of real storage that have been reserved in real storage by the address space and cannot be paged out or used by other address spaces. Expanded Frames are the number of frames of expanded storage owned by an address space. Hiperspace Frames are the number of frames of hiperspace storage owned by an address space. Hiperspace allows a program to store and retrieve data directly from expanded storage, avoiding the overhead of DASD I/O.

The Address Space Virtual Storage table view provides information about virtual storage use in three categories: Low, Extended, and Large. This new table provides tuning insight and opportunity for system and applications purposes. At a systems level, the large storage users can be identified, while at an applications level, analysis of how much storage is being used in each category as well as how much of the large storage object space is in use can be performed.

The Central Storage Frame Counts bar chart graphs the counts of central frames and fixed frames. Pages are often fixed to prevent paging delays or when certain operations require that real addresses remain constant over time.

The Fixed Storage bar chart graphs fixed frame counts in terms of Low, Extended, and Large storage allocations, in megabytes. Low storage is that below 16 megabytes (MB), often referred to as "below the line."  From 16 MB to 2 gigabytes (GB), storage is referred to as Extended or "above the line," and storage over 2 GB is referred to as Large or "above the bar."

You can link to this workspace from the Address Space Counts table of the Address Space Overview workspace.

This workspace can record history.

See also:

Address Space Overview Workspace
Address Space Storage for Job

Organization of system-level predefined workspaces

Attribute groups used by system-level predefined workspaces