[Coco] The DOS command

[Bruce W. Calkins]

There was a utility that took a basic program and placed it on track 34 
with modifications on a disk so that it ran from the DOS command.  I 
used it often to boot into menu programs for the ex-wife and children to 
get to their games easily.

Bruce W.


On 11/7/19 11:37 AM, William Astle wrote:
> 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
>>
>>
>>
>
>