[Coco] Drivewire client for OS9/68K

[Willard Goosey]

On Wed, Sep 01, 2010 at 04:45:29PM +1000, Bob Devries wrote:

> you're partly right. OS9/68000 has 28 character filenames, but still uses a 
> 3-byte lsn. Here's what the manual says:
> 
> "The filename field (DIR_NM) is 28 bytes long (bytes 0-27 of the entry) and 
> has the sign bit of the last character of the file name set. The first byte 
> is set to zero to indicate a deleted or unused entry. The address field 
> (DIR_FD) is 3 bytes long (bytes 29-31 of the entry) and is the LSN of the 
> file's FD sector. Byte 28 is not used and must be zero."

I can think of 3 reasons to do that:
1) Reserve the byte for a 32-bit LSN
2) Reserve the byte for using NULL to terminate strings (for use with
	8-bit character sets)
3) eliminate odd-length strings to keep the 68K happy.

Humm, future expansion or accomodating a CPU quirk?  The World May
Never Know... :-)

Willard
-- 
Willard Goosey  goosey at sdc.org
Socorro, New Mexico, USA
I search my heart and find Cimmeria, land of Darkness and the Night.
  -- R.E. Howard