On Tue, Nov 4, 2008 at 7:25 AM, Eris Discordia
<eris.discordia@gmail.com> wrote:
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.
DOS string routines used $ character termination. (AX = 09, DX=(address of $ terminated string) INT 21h, if IIRC).
The print routines in the BIOS I knew of took a length parameter in the CX register (also IIRC)
Why do I sometimes still yearn for the simplicity of DOS? Maybe it's Vista that makes me feel so. Maybe it was the amount of stuff we could do with so very little RAM back then. Running protected mode servers really wasn't all THAT bad. :-)
Perhaps I'm just getting old.
--On Monday, November 03, 2008 7:06 AM -0500 erik quanstrom <quanstro@quanstro.net> 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