[Coco] CoCoSDC question: default .DSK size?

[Darren A]

On Wed, Dec 17, 2014 at 10:53 AM, Allen Huffman wrote:

> Since I cannot wait until I get home to try it out (I received my CoCoSDC
> from Ed, and enclosure from Tim), I wanted to ask what the default disk
> image size is if I make one like:
>
> DRIVE 1,"NEWDISK.DSK",NEW
>
> On many of my disks, I had a small loader program I would run which
> patched DISK BASIC for 6ms step rate and 42 tracks to get a bit of extra
> room. How can I back those up? I expect it would work if I used SDF format:
>
> DRIVE 1,"42TRACKS",NEW+
> DSKINI 1
>
> ...which would send format commands out to 42 tracks, and then it should
> work, yes?
>
> Does "NEW" create a 35 track image by default, or worst-case 80 track
> (wasting space)? Or does it have nothing in it until something is written
> and it expands to that size?
>
>

There is no way to create a 42 track single-side image directly on the
CoCo. You will need a customized image file containing a JVC header.
Download the blank 40 track single-side image from the Color Computer
Archive:

<
http://www.colorcomputerarchive.com/coco/Disks/Blank%20disks/JVC/180K-RS.DSK
>

Then, using a hex editor, INSERT two bytes ($12, $01) at the beginning of
the file making the total file size 184,322 bytes. Rename and copy this
file as many times as needed onto the SD card.

The customized DSK image will auto-expand to 42 tracks (or more) when
needed. The 2 byte header will prevent the CoCo SDC from thinking these are
double-sided floppy images.

Darren