[Coco] DriveWire

[Boisy Pitre]

On Mar 6, 2009, at 7:59 AM, Robert Gault wrote:

> Boisy Pitre wrote:
>> On Mar 5, 2009, at 9:33 PM, Ryan Pritchard wrote:
>> <snip>
>>> Now where I get lost is that with DriveWire 2 you indicate I could  
>>> boot
>>> strap NitrOS-9 from a DriveWire virtual drive.  Isn't the NitrOS-9  
>>> Level 1
>>> boot diskette either 2 5.25" disks or 1 3.5" disk, since you only  
>>> include
>>> one disk image for NitrOS-9 I presume you are loading the larger  
>>> disk image.
>>> Does NitroOS-9 support for DriveWire allow for larger disk  
>>> images?  whereby
>>> the virtual drives look like larger Hard Drives?
>> Yes, that is correct. Under NitrOS-9, you can format a DriveWire  
>> disk as large as RBF will allow (4GB)
> ><snip>
>
> Ryan, I'm not so sure that Boisy answered your question completely.
>
> NitrOS-9 has a module in the kernel on track 34 called Boot. This  
> module is by default hard coded to read floppies. If you want to  
> boot from a real hard drive via a scsi or ide interface or from a  
> virtual hard drive via DriveWire, the boot module must be replaced  
> with a special one to access the correct hardware. This is done for  
> you (I think) by Cloud-9 when you purchase their products.
> The size of the drive where the main NitrOS-9 system is installed,  
> is not dependent on the interface that talks to the drive as much as  
> it depends on the actual OS-9 / NitrOS-9 software. The size of a  
> disk is stored on the disk's first sector in 3 bytes indicating  
> total sectors, DD.TOT. So you are limited to $FFFFFF sectors. The  
> sectors don't need to be 256 bytes (standard) but that is still 4GB.
>
> So when booting via DriveWire or an IDE or SCSI system, you will  
> still use a floppy. The floppy can be a virtual floppy in which case  
> it is a 35 track single sided image containing only the kernel on  
> T17 and the os9Boot file.
> You can get a feel for this with several emulators using RGBDOS for  
> emulators. Both the emulator version of RGBDOS and HDBDOS derive  
> from the same RGBDOS sold with KEN-TON SCSI hard drive systems for  
> the Coco.

Robert,

Thanks for the in-depth explanation.  Ryan, Robert is right.  A boot  
module for DriveWire exists to get the bootfile from the DriveWire  
server and bootstrap into NitrOS-9.  The NitrOS-9 disk image that will  
be supplied over the weekend will have all of this set up.  You would  
simply mount the disk image in the drive, bring up your CoCo into HDB- 
DOS and type DOS, then the booting would commence.


>
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