Predal jsem dotaz autorovi a zde je jeho odpoved:
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Now I removed this preallocation, but it resulted in more than twice lower
performance when unpacking to my 8 GB USB flash disk, which is rather old
though.
Flash disk performance strongly depends on a type of disk
controller, so, I think, there is no universal solution suitable for all
disks.
In general I think that progress is going on and controllers
are becoming more intelligent, making any special optimization for
flash disks less useful.
There is no way to switch this feature off for
users. I just removed the preallocation code and recompiled RAR when testing
it now.
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T.j. ze se to vypnout neda, ale ze to zkusil prekompilovat bez prealokace a ja tam ctu, ze vykon klesnul (lower performance) na polovinu, tedy presne obracene?
V kazdem pripade mini, ze prizpusobovat program jedne z konstrukci radice neni spravna cesta. Tak se snad dockame klice, at si to uzivatele v pripade potreby mohou vypnout.
Pro jistou jsem se jeste zeptal, jestli nedoslo k omylu:
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> It means 'WITHOUT preallocation is the performance
> LOWER?', i.
e.backwards as claims user?
Yes, exactly. And more than twice
lower. I did not expect such difference myself. I expected that performance
will be about the same before making this test.
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T.j. opravdu vypnuti prealokace ZPOMALI rozbalovani vice nez dvojnasobne, pry ocekaval, ze to na vykon nebude mit zadny vliv.