16.4 Solaris

The Solaris kernel is stored in /kernel/unix. It is structured around loadable modules: executables that add capabilities and functionality to the system. Modules add flexibility in that they can be installed and uninstalled as needed. The operating system probes the hardware each time the system boots and loads the needed modules. Modules are stored in the subdirectories of /kernel.

The following commands display information about the current system configuration (in voluminous quantities):

modinfo

Display loadable modules.

prtconf

Show system hardware configuration (peripheral devices).

sysdef

Display loadablemodules, hardware configuration, and the values of some tunable kernel parameters.

In general, little kernel configuration is required on Solaris systems, other than adding modules or drivers to support new devices when they are installed.

Vendors generally provide installation instructions and associated drivers along with their hardware. Device drivers can also be manually loaded and unloaded with add_drv and rem_drv, respectively, and other modules can be loaded and unloaded with modload and modunload.

The /etc/system configuration file allows you to specify what modules are and are not loaded and to specify the values of system parameters. The latter occurs in the section headed by these comment lines:

* set: Set an integer variable in the kernel or a module  *      to a new value.  * set scsi_options=0x58  set TS:ts_maxupri=69  set TS:ts_maxkmdpri=39

The sample set entries illustrate the format for specifying parameter values. The first command sets a flag for the SCSI subsystem. The following two commands set parameters within the TS module (corresponding to the time-sharing scheduler table), specifying the sizes of the user and kernel priority portions of the general scheduler table. These parameters must be specified when you install a custom scheduler table that is a different size than the default table.^[5]

^[5] The ts_dptbl manual page details the process for doing this, which involves creating a source file, ts_dptbl.c, compiling and linking, and installing the resulting module in /kernel/sched.

Exercise care in editing /etc/system because it is possible to create a file that leaves the system unbootable (and always save a copy of the current, working file before modifying it). For such cases, Solaris systems provide an interactive boot mode in which you are prompted for the paths to the system and kernel files. The following command may be used to boot interactively:

> b -a