Re: [ppc patch] support SCSI disks

[Hollis Blanchard]

On Oct 3, 2004, at 1:10 PM, Marco Gerards wrote:

> Hollis Blanchard <address@hidden> writes:
>
> > On Oct 3, 2004, at 4:21 AM, Marco Gerards wrote:
> > > Isn't it possible to make this a bit more generic?  So not iterating
> > > over only scsi but also over `ide' when it is available, for example?
> > > That way it is more likely the code will work on other machines as
> > > well.
> >
> > A given SCSI device could be either a byte-oriented tape or a
> > block-oriented disk. However, I do not believe that the ATA protocol
> > allows you to read a single byte, so ATA tape drives must implement
> > blocking in the hardware. In other words, it is not possible to have
> > both block- and byte-oriented device nodes representing an ATA
> > device. That is probably why I have never seen an IDE/ATA "tape" node
> > in a device tree.
>
> I never mentioned tapes...  All I currently care about are block
> devices.

Ok. I was submitting this code to solve a specific problem: on Old 
World Macintosh, I don't have a "disk" or "hd" devalias. Instead I have 
a "scsi" alias, which has the disk and tape nodes below it. The disk 
node is type block; the tape node is type char.

> > If a system does turn up later in which some additional searching is
> > needed, the problem can be resolved then. For now, my preference is
> > not to write and maintain code that isn't needed, as unneeded code can
> > only cause bugs.
>
> What I mean is not writing unneeded code, just making it a bit more
> generic.  For example scan from all the childs of aliases for block
> devices.  In your case scsi/foo will show up.

Keep in mind that on my New World Mac, I have both an "ide1" and an 
"hd" devalias. That will mean that GRUB will find and list both "hd" 
and "ide1/disk" as separate devices, even though they are just 
different names for the same thing. If you're happy with that then it's 
ok with me. Just make sure to check for both device_type == "ide" and 
"ata"; my New World says "ata" but my briQ says "ide".

-Hollis