Rockbox Technical Forums

Support and General Use => Hardware => Topic started by: Overand on January 08, 2007, 12:23:45 PM

Title: iPod Emergency Disk Mode vs. 'native' iPod OS
Post by: Overand on January 08, 2007, 12:23:45 PM
I'm starting this thread in response to this thread ( about transfers on the iPod.

So, I can verify that performance in Emergency Disk Mode is slower than in the iPod's OS on the 60GB iPod Video 5G.  I notice this most severely when copying a large (~35,000) number of small (~5-30k) files.  Because I haven't done hdtach or anything like that, I can't give hardcore details, but both modes are clearly using USB 2.0.  I'm going to do a quick, un-scienfitic benchmark in windows XP, so caching in the OS is of course at play here.

In "Emergency Disk Mode" - 456 megs in 1:35, or 4.8 megs per second.  That's just under 40 megabits, so it's clearly faster than USB 1.1's theoretical limit of 12 megabits.

In the native iPod OS, this same transfer took 34 seconds, working out to 13.5 megs per second, or 100 megabits.

I just redid the test with a few other directories, and I'm getting bandwith within the margin of error- 11.5 megs a second in iPod mode for a second transfer, etc.

Note- these are all read times.  I'm *assuming* similar performance for write time, though there may be an even more substantial difference between these.