[syslinux] Advice/directions to users of Syslinux

Thomas Schmitt scdbackup at gmx.net
Tue Jan 21 23:45:51 PST 2014


Hi,

i now realized that
  http://www.syslinux.org/wiki/index.php/Hardware_Compatibility#USB-Geometry
  http://www.syslinux.org/wiki/index.php/Hardware_Compatibility#USB-Miscellaneous
are the new wiki sections by Gene Cumm. (Sorry for not reading
them when they were announced.)

So i ask especially him whether the statement

 "An examle is a drive of 128,64,32 with a partition ending at
  127,63,32 (the last sector of the last whole cylinder)."

should be changed and expanded to

 "An example is a drive of size of 128 MB (or slightly larger)
  assumed with 64 heads per cylinder and 32 sectors per head,
  where the partition should end at 127,63,32.
  Drives larger than 1 GB should be regarded as having 255 heads
  per cylinder and 63 sectors per head. E.g. an drive of
  15794176 blocks (7.5 GB) should have its partition end
  at 982,254,63.
  Drives larger than 16434495 blocks should bear as partition
  end 1023,254,63. Setting the partition end LBA to the full drive
  size may or may not hamper its bootability."

Reasoning:

I state "assumed with 64 heads per cylinder and 32 sectors per head"
because the values of H/C and S/H are more or less a deliberate
decision at partitioning time.

I refrain from giving the drive size in CHS, because this is ambigous
until the user has chosen H/C and S/H.

I do not use digit separators with decimal naumers (15,794,176
versus 15794176) because this could get confused with the CHS
commas.

I mention the opportunity to set the end LBA higher than the end CHS
because else half of a 16 GB drive would be wasted.
But maybe one should rather state that if a BIOS is too dumb for
uneven partiton endings, then it is probably too dumb for large
partitions, too.
Any experience around ? Any opinions ?

The advise to set large drive ends to 1023,254,63 is taken from
  http://en.wikipedia.org/wiki/Master_boot_record#Partition_table_entries


---------------------------------------------------------
To the wiki admins:

I acquired a SYSLINUX wiki account: "scdbackup"
Please enable editing.


Have a nice day :)

Thomas



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