MPE/iX 5.5 Operating System Limits

Concurrent process limit
A remote logon to another MPE/iX system, (logon via a Virtual Terminal), requires 3
processes on the host system and 3 on the remote system. There will be a JSMAIN, a CI,
and a VTSERVER process on both sides. If the user runs a simple program (which does
no process handling), then there will be a total of 4 processes per logon.
Release 5.5 supports 2000 Virtual Terminal (VT) sessions. With 1250 active VT logons,
it is estimated that 8100 processes are used ((2000*4)+100). With a maximum of 8190
processes, it is possible to achieve a maximum of 2280 active logons if 2000 of these
active logons are VT logons.
8190 - 100 system processes - (2000 * 4) = 90 processes leftover.
With 2000 active VT logons it is estimated that a maximum of 30 additional active
logons is possible (90 processes/3 processes per non-local connection).
It is very important to note that many applications and third party products use process
handling. You must determine how many processes will be used by each session or job in
order to accurately predict the number of users that the system will support.
Below is a worksheet which can be used to estimate the concurrent process requirements
for a system with networked connections. If the active users are running programs which
do process handling, then the multipliers used for active jobs and sessions (local or
remote) will need to be modified.
# Active Jobs _____ x 3 = _____
# Inactive Local Sessions _____ (<- ~2500) x 2 = _____
# Active Local Sessions _____ (<- ~2500) x 3 = _____
# Inactive Remote Sessions _____ (<= 2000) x 3 = _____
# Active Remote Sessions _____ (<= 2000) x 4 = _____
+ system processes + 100
===================================================================
Total Connections _____ Total Processes _____ (<= 8190)
Although it is possible to configure more than 2500 terminal I/O devices, neither the
inactive local sessions nor the active local sessions should exceed 2500. An HP support
representative should be contacted before exceeding these limits. Also, the sum of all
remote sessions cannot exceed 2000 due to the limit on Network Servers imposed by the
NS transport layer.
Data communication servers
In addition to application programs, data communication servers also require processes.