> First approach on my laptop, quite significant. > Comparison of r/w from/to : > - the utility partition on the hd (fat32) > - the usb key > shows that read from the usb key is about 2 times slower than from the hard > disk, which is expected, whereas the write is about 20 times slower, which > seems > in deed very wrong.
> # ls -l Desktop/R174292/Dell_multi-device_A17_R174292.exe > -rw-r--r-- 1 root root 56396160 Mar 29 15:48 > Desktop/R174292/Dell_multi-device_A17_R174292.exe > copy to usb 2.0 key fat32 > # time cp Desktop/R174292/Dell_multi-device_A17_R174292.exe /media/z-PEN/ > real 1m58.760s > user 0m0.009s > sys 0m0.358s Hmm, so it transferred less than 500 kbytes/second, for that 56mbyte file copy. Somehow your write performance of 500 kbytes/second reminds me on an interesting usb flash memory performance issue I see with one of my usb flash memory devices: Apr 7 16:36:08 tiger2 usba: [ID 912658 kern.notice] USB 2.0 device (usb1976,6025) operating at hi speed (USB 2.x) on USB 2.0 root hub: [EMAIL PROTECTED], scsa2usb1 at bus address 3 Apr 7 16:36:08 tiger2 usba: [ID 349649 kern.notice] Alliance Flash Disk 17164900F0B50800 The format of my usb stick's device identification looks similar to the one you reported - both devices seem to use the same 16 character hex serial number format. In prtconf -Dv output I found these for my usb flash memory device: usb-vendor-name: 'Alliance' usb-product-name: 'Flash Disk' usb-serialno: '17164900F0B50800' usb-vendor-id: 00001976 usb-product-id: 00006025 usb-revision-id: 00000100 I guess your device uses vendor-name = 'DaneElec', product-name = 'z-PEN', and serialno = '0DF1A96051D22BC1' Now the interesting thing with my 'Alliance' 'Flash Disk' is that it is able to write reasonable fast to the raw device using wrte block sizes of 1K, 2K and 8K (2.3 mbytes/sec), but write transfer rates gets really bad when using write block sizes of 4K! But with 4K writes transfer rates to the raw device drop to 500 kbytes/sec. Like this, when writing 100mbytes to the raw usb flash memory device: # ptime dd if=flash4g.img of=/dev/rdsk/c6t0d0p0 bs=8k count=12800 12800+0 records in 12800+0 records out real 45.095 user 0.041 sys 0.641 # ptime dd if=flash4g.img of=/dev/rdsk/c6t0d0p0 bs=4k count=25600 25600+0 records in 25600+0 records out real 3:30.229 user 0.041 sys 0.521 # ptime dd if=flash4g.img of=/dev/rdsk/c6t0d0p0 bs=2k count=51200 51200+0 records in 51200+0 records out real 46.831 user 0.046 sys 0.569 # ptime dd if=flash4g.img of=/dev/rdsk/c6t0d0p0 bs=1k count=102400 102400+0 records in 102400+0 records out real 47.742 user 0.082 sys 0.975 I do remember that the preformatted fat filesystem on my usb flash memory stick used a 4K cluster size, and that writing to that stick using pcfs was extremely slow at first. As a workaround I reformatted the stick to use a cluster size of 8K, and IIRC I also tried to add the correct amount of hidden sectors so that the 8K cluster are aligned on 8K boundaries on the physical disk media. This message posted from opensolaris.org _______________________________________________ opensolaris-discuss mailing list [email protected]
