[Coco] The DOS command

[William Astle]

The DOS command reads track 34 (all 18 sectors) to address $2600. Then 
it checks to see if the first two bytes are "OS". If so, it jumps to 
$2602. Otherwise, it returns to Basic.

That means you can put any program you want on track 34 and as long as 
the first two bytes are "OS", DOS will launch it.

It may be a good idea not to assume the load address but there are no 
variants of the DOS command that I'm aware of that use a different address.

On 2019-11-07 9:26 a.m., Salvador Garcia via Coco wrote:
> I am curious as to how the DOS command (in Extended Disk BASIC) works. I looked for it and found this charming description in the Quick Reference Guide:
> 
> "DOSWith the OS-9 system diskette in Drive 0, the DOScommand boots the OS-9 operating system."
> 
> But I would like to get more technical than this. Does the DOS command always loads a specific sector from the media? If a home made DOS (i.e. anything not from Radio Shack) expects to be loaded with this specific command, what requirements does it need to satisfy?
> 
> Is there any literature out there that I can read to better understand what goes on after I enter DOS? Thanks! Salvador
> 
> 
>