AT&T 3B2/300 Technical Reference Manual page 282

- - - - - - - - - - - - - - - - - - - - - - - - - - - FUNCTIONAL DESCRIPTION
Self-configuration is done by a combination of hardware, firmware, and software supplied
functions. Figure 3-12 shows the self-configuration process. This process is also called
auto-configuration. The self-configuration process begins with firmware examining the hardware and
constructing an EDT in memory. The EDT contains information about the equipped devices. The
firmware loads the mboot program from the boot block of the designated device into memory and
executes the program. The mboot loads the lboot program from the boot device into memory and
starts it running.
/unix
/etc/ system
/boot/KERNEL
No reconfiguration is done if the date on /unix is newer than the date on
/etc/system. A preconfigured kernel is loaded into memory and executed. This
boot is faster than the self-configuration process.
The kernel is reconfigured when the system description file is booted.
Booting the /boot/KERNEL file is similar to booting /etc/system except no drivers
are configured and the process is interactive. During the boot process you are
asked to supply (input) information normally provided by the /etc/system file.
Once the lboot program has examined the EDT and /etc/system file, the proper drivers in the /boot
directory are included into the kernel. The load map of the new kernel is displayed when /etc/system
is booted. When the fully configured kernel is built in memory, the lboot program jumps to the
starting address of the kernel.
When the operating system transitions to multiuser mode, a check is made to see if the system
auto-configured. This check is done by the
/etc/ckauto command in the /etc/rc.d/autoconfig file. The
core (memory) image of /unix is copied to /unix by /etc/mkunix when self-configuration occurs. The
device nodes are automatically modified to match the hardware configuration as a function of each
device driver.
FUNCTIONAL DESCRIPTION 3-29