The Boot Monitor is firmware code in the terminal's boot PROM. The Boot Monitor performs many functions automatically and provides interactive access to Boot Monitor functions and to configuration information stored in NVRAM (non-volatile RAM).
Automatic Boot Monitor Functions
The Boot Monitor is activated when you turn on the terminal and controls the booting process as the terminal discovers its network address and loads an X server.
This section describes the automatic functions that occur when you turn on or reboot the terminal. The functions are listed in chronological order and described in more detail in the following subsections.
The Boot Monitor automatically:
The Boot Monitor tests terminal memory and the terminal's network interface. The specific tests available for and run by default on the terminal depend upon the terminal model.
You can disable these tests using the boot-test-ram parameter, but this is not recommended.
The Boot Monitor ex command displays an Extended Tests menu, which lists the tests available for each terminal. (See Table 11-2 for a list of all the Boot Monitor commands.) NCD Technical Support may ask you to run tests if the results are needed for terminal troubleshooting.
The Boot Monitor's output during terminal booting includes the results of the tests.
Keyboard Controller and Supported Keyboards
The keyboard controller is part of the ASIC (application-specific integrated circuit) in the terminal base and serves as the interface between the terminal and the keyboard hardware.
The Boot Monitor supports the following keyboard types:
By default, the Boot Monitor seeks the terminal's IP address by broadcasting alternating DHCP (Dynamic Host Configuration Protocol), BOOTP (Bootstrap Protocol) and RARP (Reverse Address Resolution Protocol) requests. These requests contain the terminal's Ethernet or Token-Ring address, which is set in NVRAM at the factory.
A host running BOOTP/DHCP and configured with information about the terminal may respond with the terminal's IP address. Depending on the protocol implementation and the information in the host's database, DHCP/BOOTP can return other information as well. For a complete list of supported DHCP/BOOTP options, see Chapter 3, Booting-Address Discovery.
Alternatively, a host running RARP and configured with information about the terminal may respond with the terminal's IP address. RARP responses contain only the address of the terminal and the address of the host that responded to the request.
If the subnet mask is not supplied in a BOOTP/DHCP response or if BOOTP/DHCP is not used for address determination, you can use ICMP (Internet Control Message Protocol) to determine the subnet mask.
Instead of using network protocols, you can set network addresses in the terminal's NVRAM. Addresses can be saved in NVRAM by using remote configuration files, terminal configuration menus, TELNET, the Boot Monitor Setup menus, or the NVRAM utility. Boot Monitor Setup menus are described in "Using Boot Monitor Setup Menus to Configure Terminals", and the NVRAM utility is described in "Using the NVRAM Utility to Configure Terminals". The other configuration methods are described in Chapter 6, Terminal Configuration Methods; Chapter 9, Using Configuration Menus; and the NCDware System Administrator's Guide for UNIX Systems.
X Server Downloading
After obtaining the terminal's network address and subnet mask, the Boot Monitor sends multiple requests for an X server and loads an X server and support files from a host answering the request or from a local file system on a PCMCIA card.
The Boot Monitor interleaves TFTP (Trivial File Transfer Protocol), NFS (Network File System), and MOP (Maintenance Operation Protocol) requests to download an X server and support files. You can use remote configuration parameters or the Boot Monitor Setup menus to disable file transfer requests selectively, and you can use the Boot Monitor Setup menus to change the order of the requests.
The Boot Monitor supports downloading from multi-homed hosts (hosts with more than one interface on the same network).
BOOTP/DHCP may also supply a specific X server filename specification. You can use the Boot Monitor's manual boot commands to override the filename specification in the BOOTP/DHCP response.
When downloading an X server using TFTP, the Boot Monitor displays the names of the downloaded file and the boot host after X server download is completed and every time a TFTP transfer is attempted.
When downloading an X server using MOP, the Boot Monitor retains the DECnet node number and displays the node number and name after X server download is completed.
To improve the reliability of downloaded files, the Boot Monitor generates UDP checksums for network packages that it transmits and verifies.
The Boot Monitor blanks the monitor's display automatically after 10 minutes of idleness to avoid a burn-in effect.
Interactive Boot Monitor Functions
The interactive components of the Boot Monitor are:
The interactive components are described in following sections.