Kontron NetBootLoader - Manual (Page 16)

ID 1022-8317, Rev. 2.0
NBL Operation NetBootLoader
Page 8
Availability of the command interpreter depends on the system status. If a valid image is not
available, the command interpreter is active as long as the operator requires it. If a valid image
is available, the command interpreter is only active for the duration of the boot wait time. If the
operator requires the command interpreter for a longer time he must terminate the boot oper-
ation before the boot wait time has elapsed.
Prior to using the network interface for remote access, Ethernet port parameters must be set
and this can only be accomplished initially via the primary serial interface.
The operator must either manually set the parameters using the NET command or dynamically
via the DHCP command. Some products require that prior to using the DHCP command, the
IP address of the CPU module be set to 255.255.255.255 using the NET command. If the
DHCP command returns a failure message, then the IP address should be set to
255.255.255.255, and the DHCP command reissued.
Once valid Ethernet port parameters have been set, the NetBootLoader may be remotely ac-
cessed either via telnet (all CPU modules) or Serial Over LAN (AM4100 and AM4101 only).
When the command interpreter is available during the bootwait time, a successful telnet login
or the initiation of a Serial Over LAN session will automatically terminate the boot operation,
and a command prompt is sent to the remote interface.
Once the operator has control of the NetBootLoader, he may perform any required action. To
continue with the operation of the CPU module, the system may either be cold started, the RS
(reset) command issued, or the RUN command issued.
2.6.3 System Booting
Assuming a fully configured system, beginning with power on (to the payload), the NetBoot-
Loader is started. It then preforms basic configuration of the system, and then waits shortly for
operator intervention. After this wait period with no intervention, the boot process continues
with the loading of an operating system either from NBL Flash or NAND Flash to the data buffer
and then starting it. Once the operating system is started the NetBootLoader is no longer avail-
able. The OS and application now have control.
While this may seem simple, control of the boot process can be very complex, depending on
the application requirements and the configuration of the system.
The NetBootLoader offers a very comprehensive set of commands not only for supporting ap-
plication development but to provide a secure and highly available system.
For example, validity control of images is supported for all images, either through CRC checks
or an md5 checksum verification. Selective loading and starting of images is provided by ap-
propriate command options for the LOAD, MD5, and RUN commands.
Passing operational parameters to an operating system is also supported by various com-
mands or configuration files, e.g. BL, CBL, FDT, nbl0..9.cfg, net.cfg, etc.
In addition, with modules that support IPMI (for example the AM4100 or AM4101), the boot pro-
cess can also be controlled via IPMI and the onboard MMC (Module Management Controller).
The following sections present the two primary methods of controlling the boot process.
2.6.3.1 Standard Boot Process
The standard boot process foresees the use of predefined NetBootLoader functionality without
external intervention at the time the system is to be booted. This is accomplished through the