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OBP FAQ Topics
Q23. What is "OBP"? Is it like a "BIOS"
on a standard desktop PC system?
Q24. Where can I get reference material for the OBP
in my Themis board or system?
Q25. Are there any OBP behaviors that I can enable,
disable, or otherwise control?
Q26. How can I view OBP variables?
Q27. How can I change OBP variables?
Q28. I once used an OBP command, but now I can't remember
its name. What can I do?
Q29. What is the meaning of some Themis-specific OBP
variables?
Q30. Can I update my OBP to a newer version?
Q31. What is the device node tree? Should I care about
it?
Q32. What is a "device alias"?
Q33. Is there anything I should know about the Universe
II VME to PCI bridge device?
Q34. Are there any caveats or warnings that I should
be aware of?
OBP Questions and Answers (for Appendix information
see link at bottom of page)
Q23. What is "OBP"? Is
it like a "BIOS" on a standard desktop PC system?
A23. OBP is Sun's OpenBoot firmware, normally stored
in a PROM device of some kind. The OpenBoot PROM, or OBP (also
sometimes called OpenBoot Program), boots the computer board
and loads the operating system, typically Solaris. This is
similar to how BIOS firmware on a PC system boots Windows
or Linux.
OpenBoot is based on IEEE Standard 1275-1994, Standard
For Boot Firmware. OBP is capable of booting the operating
system from a variety of different sources: SCSI disk or CD-ROM,
Ethernet, IDE disk or CD-ROM. OBP also provides many different
commands to perform basic hardware detection and testing,
as well as a Forth language interpreter.
Q24. Where can I get reference material
for the OBP in my Themis board or system?
A24. For all recent Themis products, Sun's "OpenBoot
4.x Command Reference Manual" applies, document number
816-1177-10. For older Themis products, Sun's "OpenBoot
3.x Command Reference Manual" applies, document number
806-1377-10. The boot-up banner will identify the core OpenBoot
as 3.x or 4.x. The hardware and software manual for your specific
model of Themis product will include additional commands and
variables added to the standard Sun OBP to accommodate special
features of the Themis hardware (e.g. - the Universe II VME
interface chip).
Q25. Are there any OBP behaviors
that I can enable, disable, or otherwise control?
A25. Yes, there are many. You can even extend OBP functionality
with an NVRAMRC script. (Example in work, to be included in
Appendix C at a future date).
Q26. How can I view OBP variables?
A26. Use the OBP "printenv" command.
Q27. How can I change OBP variables?
A27. Use the OBP "setenv" command.
Q28. I once used an OBP command,
but now I can't remember its name. What can I do?
A28. If you can remember at least a portion of the
command, you can use the OBP "sifting" command to
get a list of matching Forth command words. For example, suppose
you used the "test-nets" command some time ago and
now you can't remember anything except "test". Type
"sifting test" for a listing of all Forth vocabulary
entries that have any match on "test". The list
should jog your memory enough to recognize the "test-nets"
command.
Q29. What is the meaning of some
Themis-specific OBP variables?
A29. Details can be found in the software manual for
your particular Themis product. Some common variables:
vme32-slave-base - the 32-bit VME base address of the Themis
VME card. A read or write cycle to this VME address will cause
the Themis card to respond as slave. A mapping between this
VME address and a Solaris process's address space can be established
using sample program vme_dvma, which is included with the
Themis VME nexus driver. This allows a VME master to effectively
write to or read from the address space of a Solaris process.
vme32-slave-size - the size, in bytes, of the address window
starting at vme32-slave-base.
vme32-master-base - the starting 32-bit address of a VME memory
window that is mapped to a corresponding PCI address window
on the Themis VME card. When the UltraSPARC CPU reads or writes
to that PCI window, the cycle is propagated to the VME bus
as a master cycle. A mapping between a Solaris process's address
space and this VME address can be established using sample
program vme_rw (standard Unix file I/O) or vme_mmap (much
faster access using mmap system call), both of which are included
with the Themis VME nexus driver. This allows a Solaris process
to easily read from or write to VME addresses.
vme32-master-size - the size, in bytes, of the address window
starting at vme32-master-base.
Q30. Can I update my OBP to a newer
version?
A30. Yes, depending on which Themis VME card you have,
you can use the OBP "flash-update" or "flat-update"
command. The Themis VME card hardware manual has instructions.
(Examples are in work and will be placed in Appendix C at
a future date.)
Q31. What is the device node tree?
Should I care about it?
A31. At every power-up event the OBP probes all hardware
devices and uses the information to create a data structure
called a device node tree. The device node tree represents
the hardware detected by OBP, and it is passed to the operating
system during the boot process.
For a properly working system the end-user normally isn't
concerned with the device node tree. However, if there is
a device that Solaris cannot detect or configure then it is
often useful to reboot the machine to the OBP "ok"
prompt and see if the device is properly added to the device
node tree. (Example in work and will be placed in Appendix
C at a future date.)
Q32. What is a "device alias"?
A32. A device alias is a convenient reference for a
device node's rather complicated name. Refer to question about
device node tree above. Some device aliases are already set
up and you can also create your own, see OpenBoot 4.x Command
Reference Manual. Use OBP command "devalias" to
see device aliases on your system.
Q33. Is there anything I should
know about the Universe II VME to PCI bridge device?
A33. Under normal circumstances the Themis VME nexus
driver will handle all details of the Universe II bridge chip,
no detailed knowledge is required to make use of the VME interface.
If you are technically inclined, however, you can review
the Tundra Universe II User's Manual to learn about the register
settings. In the OBP, Themis has added a "show-universe-regs"
command that allows you to view all current register values.
In this way it is possible to get a clearer idea of the underlying
workings of the VME interface. (Avoid writing software that
tinkers with the register settings - the Themis VME nexus
driver expects to be the only software that modifies the Universe
II registers.)
Q34. Are there any caveats or warnings that I should
be aware of?
A34. Yes there are several potential OBP "gotcha's".
nvramrc Script:
The user-defined "nvramrc script", which is
optional, can influence the sequence of OBP initialization.
It is necessary to understand these details if the nvramrc
script is to be used. Refer to paragraph "Using nvramrc"
starting on page 41 of "OpenBoot 4.x Command Reference
Manual" (Sun part number 816-1177-10), or starting at
the bottom of page 36 in "OpenBoot 3.x Command Reference
Manual" (Sun part number 806-1377-10).
Changing Default input-device or output-device:
Under normal circumstances the OBP default input-device and
output-device are keyboard and screen, respectively. (If there
is no keyboard or graphics buffer then these I/O devices will
automatically fall back to serial port A, also called ttya
or TTYA.) If you need to change the defaults to ttya or ttyb,
first make sure you have the proper serial cable and a working
terminal connection. Otherwise, following the change, you
will be unable to communicate with the computer which also
means you won't be able to undo the change.
OBP Version Update or OBP Variable Corruption:
If you plan to update your OBP version make sure you have
a hard copy of all the current OBP variable settings. OBP
updates have the potential to overwrite some or all variable
settings, this is especially true if new OBP variables are
introduced in the new version. (The variable list can become
offset, effectively causing values to "shift over"
to the adjacent variable, in which case the enumerated values
could be inconsistent or meaningless.)
If the OBP variables are corrupted or accidentally set to
values that prevent the computer from booting then remove
the battery for 5 minutes - making sure to observe industry-standard
ESD precautions! Reinstall the battery and power-up the machine.
OBP default values should automatically be restored and the
computer should boot up successfully. The Ethernet address
and host ID will be lost when the battery is removed; contact
Themis Technical Support for assistance in restoring the proper
values.
Auto Boot:
If auto-boot? is set to true then make sure the boot-device
is available and ready to boot the computer. (Sometimes this
occurs involuntarily when the OBP is updated, since certain
variable settings can be overwritten. Refer to previous paragraphs.)
If the boot device is net and the network has not been configured
to boot the machine, then "ARP/RARP" packet messages
will be displayed repeatedly. This particular state usually
cannot be broken with a STOP-A (or CTRL-Break) keystroke.
It will be necessary to reboot the board and issue a STOP-A
(or CTRL-Break) before the network boot attempts resume.
To download Themis
Board and System FAQ Questions, Answers and Appendix A-B information,
please click here.
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