Re: I request inclusion of SAS Transport Layer and AIC-94xx into the kernel

[Linus Torvalds <torvalds@osdl.org>]

On Fri, 30 Sep 2005, Matthew Wilcox wrote:
> 
> There's precedent for binary data in sysfs -- pci config space is one.

In general, if the data has no semantic meaning (ie it's just a blob), and 
there really is some point to exporting it, it should be exported as a 
binary blob. There's no point in doing some random "ASCII conversion" if 
the data doesn't have any known semantics. Bytes? Words? Longwords? 
Byteorder? It's simply not a sensible operation, and the only sane 
interface is to just read a binary blob with the raw data.

That's true in general of PCI config space. Of course, _some_ parts of PCI 
config space do indeed have meaning, so you'll find the "device" and 
"vendor" and other things like that as separate nodes in /sysfs with ASCII 
representations. So sometimes you may have mixtures (but it would be 
stupid to try to "remove" the semantic data from the blob - then it would 
turn into a _true_ monster).

So it's not like binary blobs are not allowed. In general, the rule should 
be:
 - all independent values should show up as independent files (never mix 
   stuff up that you don't need to)
 - anything with semantic meaning should have the appropriate semantic 
   textual format (ie formatted ASCII, not just raw data).

The _goal_ is that you can look at sysfs with a file manager, and the 
results should make sense. 

		Linus
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