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Class 6 better than Class 10


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#1 maxbash

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Posted 27 January 2012 - 07:18 AM

I find Class 6 SD cards are usally better than Class 10 cards. If you look at the SD Class speed standard, Class 4 and 6 tests are more rigorous that insures that speed even in very random access. Of course the level off randomness differs between different boot images. My boot CD's that are painfully slow are very random. The worst is UBCD4win, which is Windows enviroment that run off a optical drive, it takes about 5 mins. or more to load. It seems most Live CDs don't do well with optical drive's glacial seek time. Though install disks and Live disks that preload to RAM (useally smaller size too) load data pretty sequentialy.

#2 MedEvil

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Posted 27 January 2012 - 03:37 PM

Seek time is no issue with SD-Cards. the difference come from the fact that loading an iso into ram means reading one big file, while booting directly, requires the loading of tons of little files.

Rearranging the files in an iso, so that they exist in the same order they get loaded, improves loading times from optical media. It does absolutely nothing to improve loading times from SD-Cards.

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#3 Wonko the Sane

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Posted 27 January 2012 - 04:32 PM

Rearranging the files in an iso, so that they exist in the same order they get loaded, improves loading times from optical media. It does absolutely nothing to improve loading times from SD-Cards.

Well, NO.

It actually does make a difference (of course NOT for RAMDISK .iso or. img booting), at least on devices connected through slowish BUSes, it is very possible that a fastish card connected on a IDE/PATA or SATA bus the difference is so little to go unnoticed .
http://reboot.pro/6041/

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#4 MedEvil

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Posted 27 January 2012 - 07:45 PM

Actually the slower the bus, the less effect has the seek time of a device.
I have never seen any speed differences based on the order, files exist on a USB-Stick and the order, they are copied off it.

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#5 Wonko the Sane

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Posted 27 January 2012 - 08:17 PM

I have never seen any speed differences based on the order, files exist on a USB-Stick and the order, they are copied off it.

I know, but others have.
It's not like if you haven't seen something it doesn't exist.... :whistling:
It may well be a black swan ;).
http://en.wikipedia....ack_swan_theory

And it seems like it is not much connected to "pure" seek or acccess times but to the *whatever* the PE 1.x does when booting:
http://www.911cd.net...pic=21702&st=52


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Wonko

#6 MedEvil

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Posted 27 January 2012 - 08:23 PM

But the fact, that no theory exists, that would explain it, without involving large amounts of magic, does! ;)

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#7 Wonko the Sane

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Posted 28 January 2012 - 01:12 PM

But the fact, that no theory exists, that would explain it, without involving large amounts of magic, does! ;)


- In theory there is no difference between theory and practice, but in practice there is. -


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Wonko




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