Keyboards (PS/2 Style)
It is possible to use common "PS/2 style" keyboards on MIPS-based SGI workstations that have PS/2 ports. Supported systems include Indy, Indigo2, O2, OCTANE, Fuel, Onyx2, Onyx 300, Onyx 3000, and Tezro. Older systems, such as the 4D series, Indigo, Crimson, and Onyx, are not supported.
Most 101-key keyboards will work on supported systems without requiring custom software configuration. Other types of keyboards may require customized keyboard mappings. Keyboard maps can be modified using the IRIX xmodmap utility.
SGI MIPS Systems, PC Keyboards, and KVMs
While many SGI MIPS systems have the ubiquitous PS2 keyboard and mouse interface, SGI elected to use the less common keyboard "scan code set 3." Scan code set 2 is more commonly used in the PC world. While most PS/2 keyboards work when directly connected to an SGI system, some KVMs seem to translate only a fairly rigid implementation of scan code 2, resulting in compatibility issues.
Some KVMs have the ability to transparently relay scan code set 3, some require a jumper or configuration change to do so, and others apparently pass everything through using the more common scan code 2. For instance, at least one model of KVM works as long as all of the systems connected are SGI MIPS systems; if one of the connected systems is a PC that uses scan 2, as soon as that system is selected, the key mapping is incorrect for the SGI systems and cannot be reset without removing the PC and restarting the SGI systems.
A little background from the pckeyboard man page:
- "The keyboard connects to the back of the system unit with a shielded partially coiled cord and is detachable at the system cabinet only. The system communicates with the keyboard via a clocked serial protocol. SGI uses keyboard scan code set 3, which sends a scan code on key press and a "break" code followed by repeating the scan code. Every key has a unique scan code. All keys function the same way, allowing the system software to use keys in any manner."
See also the article on Keyboard_And_Mouse_Sharing.
- Nekochan wiki topic on Keyboards
Scan Code Sets
The PS/2 Keyboard Interface as described at computer-engineering.org:
- Scan Code Set 1 - Original XT scan code set; supported by some modern keyboards
- Scan Code Set 2 - Default scan code set for all modern keyboards
- Scan Code Set 3 - Optional PS/2 scan code set--rarely used (aside from SGI MIPS systems)
And lastly, an indirect mention in a Belkin support document of how to apply the correct scan code to specific ports on one of their enterprise level KVMs (which may or may not work with other Belkin models): http://www.belkin.com/support/article/?lid=en&pid=F1DP108A&aid=7199&scid=0