Re: Abstraction (Was: Re: Potato->Woody)

[Andrew Sharp <andy@netfall.com>]

Onno Benschop wrote:
> 
> Ok, ok, I'll bite.

Don't you mean `bark'?  ~:^)

>> So, then someone asks, how come reiserfs doesn't work on sparc.
> 
> I wonder what am I missing?


A lot.

First, get a book on Unix kernel development and read it
completely.  Then, design and write a journaling filesystem for any
Unix and see how long it takes for you to get a version that runs
for longer than ten seconds without panicing the kernel.  After you
get it to run for several minutes without crashing, then you will
already know the answers to this and many other questions,
Grasshopper.  ~:^)  Oh yeah, and don't forget that you have to port
every utility that has knowledge of the file system structure,
including, but not limited to: mkfs, fsck, dump, restore.

Second, someone posted a message showing that it does run on SPARC.

Third, a file system is responsible for the meaning and content of
it's on-disk data structures; the disk driver layers have nothing to
do with that.  If the filesystem code inadvertently assumes a
certain endianness with respect to how the bytes come off the disk
and are placed into words, then things can get broken on machines
where that assumption isn't correct.  It's a lot easier than you
might think for this kind of error to occur.

Getting any piece of kernel code to work starts by getting it to
work on a specific platform first, then porting/testing it on other
platforms as time/demand permits.  You might try digging into the
list of current bugs for reiserfs to become acquainted with the
level of difficulty of the topic you are thinking about while
sticking pencils in the ceiling tiles.  ~:^)

a