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Re: Option -sector:0x00000002

Alex Granovsky
gran@classic.chem.msu.su


Hello,

Firefly I/O routines cannot properly handle some types of random
access files that contains more than 2147483647 logical sectors.
The default sector size is 512  bytes hence the default limit is 1 TB.
Option -sector:0x2 doubles the default sector size. This allows to
handle random access files of up to 2 TB.  Option -sector accepts any
number that is a power of two. E.g. to handle random access files of
up to 16 Tbytes one may use -sector:0x10

This option does not degrade performance but slightly increases the
size of random access files. The larger is logical sector the larger
is disk overhead, as Firefly aligns records in random access files at
the logical sector boundary. Larger logical sectors result in larger
overhead. This is very much like the cluster size of file-systems
affects the wasted space on the disk.

Kind regards,
Alex



On Mon Jun 13 '16 6:16pm, GrEv wrote
------------------------------------
>Hello,

>I wonder if the use of -sector:0x00000002 option in the command line to launch FF can lead to some slowing down of the calculation?

>Best regards,
>Evgeniy


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