[Coco] OS-9/68K raw disk access syntax

[Joel Ewy]

On 01/01/2016 10:43 AM, Joel Ewy wrote:
> So, as another attempt to make a disk image file on the MM/1, I 
> thought I would write the floppy image to a ramdisk (since I don't 
> have a working hard drive on the MM/1 at the moment), then compress 
> it, and see if I could squeeze it back on a FAT formatted floppy 
> disk.  I thought I might be able to do this like so:
>
> copy /d1@ /r0/image.dsk
>
> Copy complains:  "can't get file descriptor.  Error #000:214". errmsg 
> says "The file was found, but is inaccessible in the requested mode.  
> Check the file's owner ID and access attributes."
>
> The OS-9 manual mentions that you need to be superuser to use raw disk 
> access, and it sounds like maybe that is tripping me up here. But 
> there are no user accounts set up on this boot floppy, as far as I can 
> tell.  Wouldn't superuser be the default, or is there some 'su' 
> equivalent I'm forgetting about?  Or do I just have the syntax wrong?
>
> JCE
>
It turns out that the copy command above did create a floppy-disk-sized 
file in the ramdisk, but ded says it was filled with 0.  'procs' tells 
me that I am user 0.0, so it likely isn't a permissions problem.  After 
re-reading page 7-6 of the OS-9 Technical Manual, I'm wondering if maybe 
a program doing raw disk access needs to be aware that it is doing so, 
and deal specifically with sectors, rather than higher level abstractions.

JCE