TS/MP 2.5 System Management Manual

In response to the START SERVER command, the PATHMON process performs these startup
operations for each static server process in the server class:
• Creates and starts the server process by running the program specified in the PROGRAM
attribute of the SERVER definition, using all parameters previously indicated by the SET
SERVER commands.
• Sends a startup message to the server process, describing that process’ environment. This
message indicates the names of the input and output files and the default volume and subvolume
used by the process, and any optional message text.
• Passes any variables or parameter assignments to the server process: ASSIGN and PARAM
assignments for Guardian server processes; and ARGLIST and ENV parameters for OSS
servers.
NOTE: To start a server that is frozen (with the FREEZE command) and then stopped, you must
first issue the THAW command. For more information, see “Stopping SERVER Objects” (page 78).
The exact server startup protocol is as follows:
1. The PATHMON process creates the server by calling the NEWPROCESS or PROCESS_CREATE_
procedure.
The server process context includes all DEFINEs specified in the server class configuration
(using the SET SERVER DEFINE command).
2. The PATHMON process opens the servers, sends the server a startup message, and closes
the server.
The startup message has a header that is constructed from what you specified for the IN, OUT,
and VOLUME attributes in the SET SERVER command. If you specified a character string for
the STARTUP attribute, that is also included.
3. If the server replies with a value of 70 (FECONTINUE) to the startup message, the PATHMON
process sends variables and parameter messages to the server.
The ASSIGN messages are constructed directly from the information you provided for the ASSIGN
attribute to the SET SERVER command. The PARAM message contains one item for each attribute
value you specified for the PARAM attribute of the SET SERVER command. The number of the
processor not chosen as the primary processor is reported in the BACKUPCPU attribute, which the
PATHMON process adds to the PARAM message. For a description of how this value is chosen,
see the information about CPUS attribute of the SET SERVER command.
When starting a server class, the PATHMON process repeats the server startup operations for the
total number of static server processes defined by the SET SERVER NUMSTATIC attribute.
Dynamic Server Processes
A dynamic server is a server process that the PATHMON process creates when a link manager
asks for a link and no links to static servers are available. Note that if the link manager has
determined that no more static links are available, it asks for a new link only after send requests
have queued for the time period specified by the CREATEDELAY attribute for the server class.
A link manager always tries to satisfy a send request with a static link if one is available. If a
dynamic server process sits idle for the time limit defined by the DELETEDELAY attribute for the
server class, the link manager returns the link to the PATHMON process.
If high system performance is required, it is recommended that you not use dynamic server processes
because they incur a startup penalty as part of the transaction path.
You determine the number of dynamic servers for a server class with the SET SERVER MAXSERVERS
and SET SERVER NUMSTATIC attributes. If MAXSERVERS is 4 and NUMSTATIC is 2, this server
class can have two dynamic servers.
Starting SERVER Objects 77