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

On 3/28/2011 4:31 PM, Witold Baryluk wrote:

On 03-28 12:43, Robert Garron wrote:

Joel,

Can your group do what Bill is asking below?
Similar to the change of 36 gig to 300 gig...

Regards,
Robert

----------  Forwarded Message  ----------

Subject: Disk drives
Date: Mon March 28 2011
From: Bill Parke<Bill.Parke@access3000.net>
To: Robert Garron<Robert.Garron@access3000.net>, Ken Ballou
<thecryptoboy@gmail.com>

Ask Joel if SATA drives, with 4KB block size drives can be supported.
Anything
over 2.7TB disk drives are not addressable in 512 byte blocks.

Also, I believe the general Grub 2 (We need to get to it) supports GPT drives
so
there may or may not need to be microcode changes needed.   Or the Grub folks
may have already doen this (I would expect).


AFAIK no Alpha machine uses Grub for booting.
MILO or aboot is used in most cases. Maybe Sometimes directly SRM, or AlphaBIOS
as a hack, but not a grub.


We will need Debian's test harnesses and test modules used for old Alpha and
new
AMD (to adapt).


Alpha have 8k memory pages, but it works for example with smaller block-size,
in example when using ext3 it will use normal to ext3 a 4K (as using 8K,
will make such this unreadable under IA-32, which have upper limit of 4K
file system blocks under Linux, as it is a size of page).

As of disks, I have a one disk (Western Digital Caviar Green 1.5TB),
which I can attach for a brief period of time into my Alpha,
using PCI SATA controler. But I think other people is already using
such disks in their machines. Can anybody confirm?

Anyway 4k blocks SATA devices are still adressed using 512 byte unites,
or maybe something changed in SATA-3 ?


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


Bill Parke EBD 1981-2000
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