[Coco] The DOS command

[Alex Evans]

One interesting factoid is that early versions of DECB don't have the
DOS  command. Because of this, the OS-9 Level I distribution boot disk
is a hybrid RSDOS/OS-9 disk that contains DOS.BIN on the RSDOS part of
the disk.

On Thu, Nov 7, 2019 at 11:45 AM William Astle <lost at l-w.ca> 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
> >
> >
> >
>
>
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