[CentOS] SiL311x SataRaid (sata_sil)

[Bryan J. Smith]

On Sat, 2005-06-18 at 11:56 -0400, William Warren wrote:
> not necessarily.  I had a friend put linux on his computer but 
> his bios doe snot support 48 bit LBA so he only saw 30 gigs both 
> in the bios and in linux itself.

Check the jumpers on the disk.  Some have an option to limit the
number of heads reported to 16 (not 255) and/or cylinders to 1024.  That
would cause an issue.

BTW, the ATA28 (28-bit) limitation is _not_ 33.8GB (32GiB), it's:

  16,384 cylinders (14-bit)
      63 sectors/cylinder (6-bit)
     255 heads (8-bit)
     512 bytes/sector 
 ========
   137GB (128GiB) (14-bit + 6-bit + 8-bit = 28-bit)

Now if you're limiting heads to 16 (instead of 255), that can cause the
limitation by which the maximum number of cylinders is 65,536 (16-bit)
because some OSes have a limitation on the number of cylinders in their
geometry.

  65,536 cylinders (16-bit)
      63 sectors/cylinder (6-bit)
      16 heads (5-bit, 10000, instead of all 1s)
     512 bytes/sector
 ========
    33.8GB (32GiB)

That's a common issue cause by the disk being jumpered to report only 16
heads.


-- 
Bryan J. Smith                                     b.j.smith at ieee.org 
--------------------------------------------------------------------- 
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