Dvorak vs QWERTY scancodes

Question

Do Dvorak keyboards use the same scan codes as QWERTY keyboards? I mean, does the letter U have the same scan code on both types of keyboards?

Or, is it more like taking a QWERTY keyboard and moving the plastic key tops around to mod it into a Dvorak keyboard?

Thanks.

Answer 1

Do Dvorak keyboards use the same scan codes as QWERTY keyboards?

This has no single answer, but the typical and recommended approach is that scancodes are attached to positions on keyboard, but usually named according to the "default" QWERTY layout. See ISO 9995 for the main scheme and scancode set descriptions. For example, position D01 has code 0x10 in PC set 1 despite it is Q on QWERTY, A on AZERTY or single quote on Dvorak.

The USB "HID usage tables" document explicitly says:

Note A general note on Usages and languages: Due to the variation of keyboards from language to language, it is not feasible to specify exact key mappings for every language. Where this list is not specific for a key function in a language, the closest equivalent key position should be used, so that a keyboard may be modified for a different language by simply printing different keycaps. One example is the Y key on a North American keyboard. In Germany this is typically Z. Rather than changing the keyboard firmware to put the Z Usage into that place in the descriptor list, the vendor should use the Y Usage on both the North American and German keyboards. This continues to be the existing practice in the industry, in order to minimize the number of changes to the electronics to accommodate other languages.

After scancodes are translated to hardware-independent codes, layout translation is applied and this is where difference between takes place.

Answer 2

Yes and No

Key-codes specify the position

Usually scan code applies to the key position (not letter), and is the same for all keyboards.

For example my key-caps are printed for querty, but the OS (well actually the windowing system) maps them to dvorak (so long as I don't look down it is ok).

Sometimes key-codes, change

Some keyboards, move the position of the key-codes. This is done so that they work on systems that can not have the keyboard layout changed. Some have a switch, to change between dvorak and querty.