[Coco] The DOS command

[Allen Huffman]

Carl England’s SUPER BOOT was the best I used for this. Look for it in the CoCo archive.

> On Nov 7, 2019, at 11:49 AM, Bruce W. Calkins <brucewcalkins at charter.net> wrote:
> 
> 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
>>> 
>>> 
>>> 
>> 
>> 
> 
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