Global Keywords

Global keywords specify system-wide definitions. The ident keyword identifies the kernel that you are building. By convention both the kernel configuration file name and the ident kernel name are either the uppercase node name or AFS, for AFS installations, such as: ident MYSYS

Duix does not use time zone information. The timezone keyword sets the initial value of the kernel's tz structure, which is used only for backward compatibility with executables that use the gettimeofday function. The tz structure maintains its initial value as long as the system is in single-user mode. The tz structure is overwritten by the local time zone when the system boots to multiuser mode. By default, the timezone keyword is specified as follows:
timezone 0 dst 0

Process memory size limits are defined by:

dfldsiz Default data segment size limit
maxdsiz Maximum data segment size limit
dflssiz Default stack size limit
maxssiz Maximum stack size limit

The sys_v_mode keyword, when set to 1, handles GID and file mode of newly created files according to System V functionality that is enabled and directly affects the open(), creat(), and mkdir() system calls.

The following keywords define the System V parameters for messages, semaphores, and shared memory:

System V Messages Keywords
Keyword	meaning
msgmax	Maximum message size
msgmnb	Maximum number of bytes on queue
msgmni	Number of message queue identifiers
msgtql	Number of system message headers
System V Semaphores Keywords
semaem	Adjust on exit maximum value
semmni	Number of semaphore identifiers
semmns	Number of semaphores in the system
semmsl	Maximum number of semaphores per ID
semopm	Maximum number of semaphores per semop call
semume	Maximum number of undo entries per process
semvmx	Semaphore maximum value
System V Shared Memory Keywords
shmmax	Maximum shared memory segment size
shmmin	Minimum shared memory segment size
shmmni	Number of shared memory identifiers
shmseg	Maximum number of attached shared memory segments per process

The maxusers keyword defines the number of simultaneous users that your system can support without straining system resources. Default values is 32 for systems with $<24$ MB memory and is used to tune system resources and to size the table of active processes. For heavy work loads increase maxuser to 64 and rebuild the kernel. Note that the following keywords depend on maxusers:
maxcallouts, nclist, nquota, nvnode, ndquot, task_max.

Pay attention to the following keywords:

nclist buffers for terminal I/O
max_vnodes maximum number of open VFS files (memory dependent)
maxuthreads maximum number of threads per task for
threadmax maximum number of threads system wide
If the system reaches the limit, it displays:
fork/procdup: thread_create failed. Code: 6
task_max limit on number of running processes
Initially set to: 1+(20+(8*maxusers))
The system displays the following message if limit is reached:
pid: table is full
Message is found in /var/adm/messages and in the kernel
event-logging file
maxuprc maximum number of processes for nonprivileged user
maxcallouts maximum number of callouts on the system. If its size
is not enough the system panics with the message
timeout table overflow
Dynamic with new Duix 4.0. For older systems, to determine the
current number of callouts, enter the following commands:
# dbx -k /vmunix
(dbx) p ncallout
1316
(dbx) q