SYSGEN PARAMETER

GT.M CONSIDERATIONS

GBLPAGES

For the run-time libraries: 1500 pages VAX

4000 pages AXP

For each simultaneously installed GT.M application image: 1 page per block

For each BG segment: ((blocksize/512) * .7) * #global_buffers + 2150 + lock_space

For each MM segment: (File_size + journal_buffer_size + lock_space + 2) pages

GBLPAGFIL*

For each BG segment:

((global_buffer_count * block_size/512) + global_buffer_count/10 + journal_buffer_size + lock_space + 29) pages + 2150 + lock_space

For each MM segment: (journal_buffer_size + lock_space + 2) pages

GBLSECTIONS

For the run-time libraries: 7 sections

For each simultaneously installed GT.M application image: 2 sections

For each simultaneously active BG database segment: 1 section

For each simultaneously active MM database segment: 2 sections

NOTE: The number of concurrent users of any given file does not effect these requirements

LOCKIDTBL

For each simultaneously active

GT.M process: 3

database segment: 1

database journal: 1

RESHASHTBL

LOCKIDTBL/4 rounded up to the nearest power of 2

VIRTUALPAGECNT

(VAX only)

For the run-time libraries: 1500 pages

For the largest GT.M image (including ZLINKed routines) : 1 page/block

For the process that uses the largest amount of memory: sufficient data space

For the sum of all BG segments accessed by the process that uses the largest amount of memory:

((global_buffer_count * block_size /512) + global_buffer_count/10 + lock_space + 29) pages

For the sum of all MM segments accessed by the process that uses the largest amount of memory:

(File_size + lock_space + 2) pages

NPAGEDYN

This parameter controls the amount of non-paged dynamic memory available to the system. If NPAGEDYN is too small, OpenVMS performance becomes very poor. A necessarily large NPAGEDYN deprives users of working space. NPAGEDYN can be set empirically by starting with a generous value, then monitoring the use of the memory it provides, and adjusting it as needed.

SYSMWCNT

This parameter controls the target size for the system working set. Because GBLPAGES are in the system working set, coordinate SYSMWCNT revisions with changes in GBLPAGES. If you use AUTOGEN, it changes the SYSMWCNT by one (1) for each 128 pages of change in GBLPAGES. Values of SYSMWCNT that are not matched to the configuration can cause such severe OpenVMS thrashing that response times for simple tasks may be measured in hours.

WSMAX

This parameter controls the largest working set permitted for the system. M string facilities and GT.M local variables, which are essentially limited only by OpenVMS address space, usually lead to images which require large working sets. Such working sets are categorized in the OpenVMS documentation as typical of AI applications. Working sets can also be set empirically by starting with a large value, monitoring actual usage by a range of users and adjusting as needed.