[Coco] Nitr0S-9 question

[Robert Gault]

Becker, Gary wrote:
> Am I right to assume that os9gen has an issue with larger drives? It
> appears in the os9gen code the sector buffer is 1024 bytes long. So when
> os9gen goes to read the allocation bit map to mark the boot track bytes
> and there is more than 1024 bytes, there would be an error.
> 
> What is the preferred method of writing the boot track to a larger
> drive?
> 
> 

The current source code does assign sectbuff rmb 1024, but that will 
only effect large drives if you insist on keeping it.sas to a very small 
number. That value, reported as sas by dmode and dd.bit in the drive's 
lsn0, represents the number of sectors per bit in the allocation map. 
Even for a floppy, that value is 8. On the default 129MB emulator hard 
drive, the value of sas is 32.

The point being that dd.bit can be any power of 2 that will fit into two 
bytes. If you use the largest size for dd.bit, that is 32768 sectors per 
bit in the allocation map. That should mean you could address 33.6 
million sectors or 8.59x10^9 bytes of drive at 256 bytes per sector. Is 
that a large enough drive for you? :)


Where you place a boot track (or even os9boot) on such a drive depends 
on the hard drive system in use. Currently available systems from Cloud9 
using HDBDOS don't have the boot track within the OS-9 portion of the 
drive. RGBDOS for emulators again does not put the boot track in the 
OS-9 partition. I don't know what other systems such a Burke&Burke did 
but they are no longer available.