[Coco] Re: Disk Basic and 512 byte block floppies.

[Arthur Flexser]

On Wed, 21 Jan 2004, Torsten Dittel wrote:

> > Weird sized sectors (along with weird sector numbers, etc.) have been a
> > popular device used in CoCo copy protection schemes.  Basic's BACKUP
> > command won't work properly with such disks.
> 
> Wasn't "Graphicom" using a strange diskette format using 1024 Byte
> sectors (which allows more to write on the disk because there's less
> sync overhead)?
> 
> Torsten

No, I believe Graphicom just altered Basic's default skip factor--the
numerical difference between the sector numbers of adjacent sectors on a
track (more or less) so that the desired sector would tend to require less
rotation of the disk to get it under the head when it was needed. (An
obscure feature of Basic's DSKINI command is that you can specify a skip
factor other than the default of 4, e.g. DSKINI 0,3.  Four was selected by
Microsoft as optimal under Basic, but other applications, such as
Graphicom, might have more efficient disk access with a different skip
factor.  Depends on how much time is required for the code that is
executed between successive sector reads.  I think Graphicom used a skip
factor of 1.)

Art