MPE/iX 5.5 Operating System Limits

NOTE: Although it is possible to mount this number of disk drives on a system, putting
them all in a single volume set with a heavy transaction load may cause problems. Please
see your systems consultant.
(3) 3 digit ldev numbers
In MPE iX 5.5 the maximum number of devices is limited to 4679. This value will also
be the maximum LDEV number tolerated by NMMGR and SYSGEN. The maximum
number of terminal devices connected via DTCs is 4649, which leaves 30 empty device
numbers for other peripherals.
(4) NMMGR config limit
The utility program NMMGR.PUB.SYS will not allow a user to configure more than
4649 terminals (connected via DTCs). This value was chosen to be 30 less than the
maximum number of devices. Being able to configure 4649 terminals does not mean that
MPE will support 4649 sessions. ( See the JOB/SESSION section of this document for
more information).
NOTE: Serial printers are also configured as terminals using NMMGR. The total number
of serial printers and terminals cannot exceed 4649. The maximum number of serial
printers that is supported varies, depending on the system model and the types of printers
that are being connected. Refer to the Systems Configuration Guide for specific details.
File system:
Item Limit Description Resource Table
1 16384 Concurrent Writers of Msg File NM Writer ID Table
2 16384 File Open (G-Multi or Job-Multi Access FS GDPD Table
3 1024 File Open (per process) PLFD
4 ~8000000 Open Msg Files (w/o timed reads) NM IPC Table
4 ~5714285 Open Msg Files (w/timed reads) NM IPC Table
5 5460 Open Multi Access CM Files FMAVT DST
6 2330 Open non Sharable Devices I/O Device Directory
7 128 User Logging IDs Log ID Table
8 128 User Logging Processes Log Table
9 1140 Process Per user Logging ID Log Buf DST
(1) NM writer id table