> i think it's a tradition at this point to use 0x20 and not 0x00 to
> fill a fixed-with signature. ata identify device uses 0x20 to fill
> out fixed-width fields like the serial number. i'd be interested
> where this tradition popped up. 0 would make more sense.


I risk being wrong--as always--and say it must have popped up in a normal
ASCII environment. 0x20 = 32, the ASCII code point for a simple whitespace.
BIOS routines know how to display a whitespace, or any ASCII character, in
text mode. I remember somewhere back in time I could load AL with an ASCII
character, call interrupt 0x0A service 0x0E, and have the character printed
on the screen and the cursor moved one character to the right. This was
(is?) fairly standard and time-proven. And it worked (works?) everywhere,
at least in the PC world.

--On Monday, November 03, 2008 7:06 AM -0500 erik quanstrom
wrote:

>> This courtesy of the ACPI spec: ""RSD PTR " (Notice that this
>> signature must contain a trailing
>> blank character.)"
>>
>> So where do we get the guys who design this stuff? Can we send them
>> back? Or put them in an infinite loop in a time machine (oh wait see
>> the subject).

>
> i think it's a tradition at this point to use 0x20 and not 0x00 to
> fill a fixed-with signature. ata identify device uses 0x20 to fill
> out fixed-width fields like the serial number. i'd be interested
> where this tradition popped up. 0 would make more sense.
>
> - erik
>
>