Support and General Use > Hardware
ipod 5.5gen 80gb's test disk result
isanggon:
I found my 80g's test disk result shows very slow on 512 byte writes are 23 KB/s or less!
Create and delete counts at the top are lower than 30gb.
I wonder this problem is mk8011gah's specific problem or ipod 80g mainboard's common problem.
And another thing,
Can I change this hdd to mk1214gah? Is it work on ipod 80g's mainboard?
saratoga:
Heres the SVN message when support for the 80GB ipod was added:
--- Quote ---"ATA driver: * Support for drives with large physical sectors and no support for partial access in the firmware (i.e. Toshiba MK8010GAH - iPod G5.5/80GB). Sequential writes with a single 512-byte buffer to that disk are really slow, so this is an intermediate solution that allows to adjust the FAT driver and the file system gradually. * Assume multisectors = 16 if the value reported by the drive is invalid (also MK8010GAH)."
--- End quote ---
isanggon:
Thank you for quick answer. Then, it's harddrive specific problem.
dreamlayers:
4096 byte writes are so much faster that they should maybe be used instead.
For example take a look at this test disk result. (That's the unboosted result without the patch.)
Suppose a 512 byte write involved reading a 4096 byte block, altering a 512 byte part, and writing back the 4096 byte block. To keep it simple and pessimistic, let's just use the slowest 4096 byte speed, 2313 KB/s.
(2313 * (512 / 4096)) / 2 = 144.56 KB/s
That's quite an improvement over the fastest 512 byte write speed of 23 KB/s!
The code is already present in firmware/drivers/ata.c. Look at what MAX_PHYS_SECTOR_SIZE does. It could maybe use a tweak though, only increasing how many sectors are written at a time because the current 512 byte read speed is similar to 30 gig iPods.
Edit: On second thought, why not just enable write caching? You do have a dependable power source: a battery which the user cannot remove and clean shutdown before the battery gets too low. All that's needed is a set features command to turn it on, and probably a flush before sleep.
isanggon:
That's great idea. But sadly, I sold my 80g. It's disk speed was horrible. :-\
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