[Coco] DW3 descriptor info question

[Boisy Pitre]

Tim,

The NitrOS-9 format command computes the total number of sectors for a  
device as follows:

	(C*H*(S-1))+T0S

Where C=Cylinders, H=Heads, S=Sectors, T0S=Sectors in Track 0

The format command in toolshed uses options -t for tracks (cylinders)  
and -st for sectors/track.  -ds and -ss set up 2 heads and 1 head,  
respectively.  There is no option for track 0 sector size, since this  
is a physical requirement and not a logical one.

Alternatively you can use the -l option to specify the number of  
logical sectors and forego the use of the above options; this option  
automatically computes optimal values for C/H/S based on the number of  
logical sectors requested.

Hope this helps.

Regards,
Boisy G. Pitre
--
Tee-Boy
Mobile: 337.781.3570
Email: boisy at tee-boy.com
Web: http://www.tee-boy.com

On Mar 26, 2009, at 6:50 PM, Tim Fadden wrote:

> Hi,
>
> I was wondering about  the device descriptor for the /x# devices  
> under Nitros9.
> I am thinking that the only time the device information is used, as  
> reguards to the geometry is when the disk is formatted. And I do  
> know that backup wants the two disks to be the same before it will  
> work. And as to imbedded scsi drives, it is ignored all together  
> except to calculate the total number of sectors, and cluster size,  
> as the numbers are not the actual geometry of the disk any way, and  
> the disk formats itself.
>
> Sample:
>
>       dmode /h0
>
>        nam=h0 mgr=RBF ddr=SCSISYS
>        hpn=07 hpa=FF5B drv=00 stp=00 typ=80 dns=90 cyl=040C sid=0C
>        vfy=01 sct=0021 t0s=0021 ilv=01 sas=10 wpc= ofs= rwc=
>
> When using os9.exe from the toolshed, only the total number of  
> sectors is provided, so geometry is not used there.
>
> Now to the question!  When using format with the /X# disks, just  
> which values does it look at?
> I would think only cyl, sid, sct, and t0s, in order to calculate the  
> number of sectors.
>
> Any questions, or input is welcome.
>
> Tim
>
> P.S. How long must a person be on the list before they are not  
> considered fly-by-night, and are eligible to answer posts in an  
> attempt to help otheres?  ;-)
>
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