[Coco] Disk EDTASM & text files

[Robert Gault]

Willard Goosey wrote:

> I've been doing some groundwork for development with Disk EDTASM,
> writing include files with all the various equates for ROM calls and
> for "Color TRS-DOS," such as it is.
> 
> One of the things that had been bothering me about this is that if I
> edited a file with my favorite CoCo3 word processor (Simply Better) I
> couldn't get EDTASM to load it.
> 
> I finally took a look at the edtasm disk's directory with a disk
> editor, and noticed that edtasm sets the record-length word.  This
> isn't a DECB thing, but is something the DOS adds, using two of the
> otherwise unused bytes of the directory entry.
> 
> So it was a fairly simple matter to hack up a little basic program to
> "fix" a file's directory entry with a record-length of $0001.  
> 
> During testing of this, I also discovered that Simply Better doesn't
> do anything with the unused half of a directory entry, leaving it as a
> string of $FFs if that's what it was.  The usual thing is to fill in
> zeros.  
> 
> So, while EDTASM doesn't require the record-length field to have a
> necessarily valid value (0 works!), $FF confuses and enrages it. :-)
> 
> Willard
In my experience, DECB always sets the second 16 bytes of a directory 
entry to $00s. The DOS that comes with Disk EDTASM+ adds record lengths.

The only time I have consistently had problems with "bad" record lengths 
is when PORT.EXE is used to move files from the PC to a .dsk image. This 
program never changes the second 16 bytes but leaves them as found. In 
most cases, that means all $FFs.