On Tuesday 05 February 2013, Csordás Csaba Ifj. wrote:
Hi,
I'm having troubles at the first step: determining the erase block size. The strange results are below. The original FAT layout was not saved when the drive was purchased.
# lsusb Bus 004 Device 002: ID 125f:c82a A-DATA Technology Co., Ltd.
# fdisk -l /dev/disk/by-id/usb-ADATA_USB_Flash_Drive_1061309422330015-0:0
Disk /dev/disk/by-id/usb-ADATA_USB_Flash_Drive_1061309422330015-0:0: 7873 MB, 7873757184 bytes 180 heads, 14 sectors/track, 6102 cylinders, total 15378432 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk identifier: 0xf65985aa
Device Boot Start End Blocks Id System/dev/disk/by-id/usb-ADATA_USB_Flash_Drive_1061309422330015-0:0-part1 2048 15378431 7688192 83 Linux
The size is a multiple of three, so you might want to retry with
# for i in 1 2 4 8 16; do echo -e "\n\nbs=$[$i*1024]"; flashbench -a /dev/disk/by-id/usb-ADATA_USB_Flash_Drive_1061309422330015-0:0 --blocksize=$[$i*1024]; done
--blocksize=3072.
If that does not help, you can run the other tests after guessing an erase block size, because sometimes the -a test does not reveal anything at all.
My first guess for this device would be a 6 MB erase block size, followed by 8 MB, 12 MB, and 4 MB.
Arnd