Re: current status of alpha in squeeze - Storage Question - we will need to store the code some where - Fwd: Disk drives

[lsorense@csclub.uwaterloo.ca (Lennart Sorensen)]

On Mon, Mar 28, 2011 at 07:01:23PM -0400, Bill Parke wrote:
> As I don't have any of the various vendors disks.  I would expect 
> somewhere, soon they will have drives that kowtow to 512 byte block to 
> help windows and MBR booting.   I know WD has a Address+1 patch to make 
> MBR work in 512byte mode.
>
> Since the LBA addressing tops at 2.7TB, I don't know if you can get at 
> the full 3TB without there being some way to address it in 4K chunks.

LBA these days do 48bit sector numbers on ATA and 64bit on some higher
end controllers.

The DOS MBR partition table is limited to 32bit sector numbers.  GPT has
no such problem.  It is not an LBA problem.  Purely a partition table
limitation.

Now what the Alpha firmware supports is a different issue being that it
isn't exactly cutting edge anymore.

> Since it is the near future though, has better fault (per block at least) 
> tolerance ( 3 bits correction, I may be wrong) and reading/writing is 4K 
> chunks is much more efficient than 8 512 byte reads, and writing 512 
> means that the drive reads the 4K block, puts the 512 bytes in the right 
> place and re-writes it
> we can still make it all behave better, possibly.

Using 4k or larger filesystem blocks and 1MB partition alignment seems
to be the current method in use.  Makes SSDs happy too.

> Yes, I forgot about Milo, and we might need to play in the boot prom.  
> (It has been a few years).)

-- 
Len Sorensen