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

[Robert Gault]

x0remery at dsbmail.itg.ti.com wrote:

>>>>>I formatted a 720K 3.5 inch floppy with 512 byte sectors
> 
> 
> Is this basically what is done when you patch RSDOS to use 80 tracks of a floppy?
> That does allow the full 720K access, one half at a time. I have a program (by
> Colin Stearman) that patches RSDOS and most or all related commands to do this.
> 
> The limitation is the number of drives you can have files open on at the same
> time,
> unless you tell the program to relocate Basic's GAT table.
> 
> I've been thinking of writing a utility to easily transfer files from 35/40 track
> floppies to 72 or 80 track floppies. If I made an 80 track RSDOS floppy,
> does that mean WinXP could read it?
> 
> Bob
> 

It is possible to hack Disk Basic (if in RAM) to use any track and 
sector numbers you want. However, that will only get you 40 or perhaps 
41 tracks per disk side and at 256 byte sectors.

Some third party OSes for the Coco make use of both sides of the disk to 
give you a double sided 80 track disk with 40 per side; still 256 byte 
sectors.

PCDOS under OS-9 is a program that will read MSDOS disks with 512 byte 
sectors if a special cc3disk is used. Based on some of the traffic here, 
one could write a Basic program to read 512 byte disks that have a Disk 
Basic directory structure making use of the full 512 bytes.