Hi, When I attach pen-drive, I am seeing following logs. And when I remove pen-drive, file system does not unmount for 10-15 secs. [ 35.183406] usb 1-1: new full-speed USB device number 2 using dwc_otg [ 35.440812] usb 1-1: not running at top speed; connect to a high speed hub [ 35.456740] usb 1-1: New USB device found, idVendor=0781, idProduct=5572 [ 35.479144] usb 1-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3 [ 35.501552] usb 1-1: Product: Cruzer Switch [ 35.513147] usb 1-1: Manufacturer: SanDisk [ 35.535614] usb 1-1: SerialNumber: 4C532000050910112450 [ 35.571416] scsi0 : usb-storage 1-1:1.0 [ 36.619687] scsi 0:0:0:0: Direct-Access SanDisk Cruzer Switch 1.20 PQ: 0 ANSI: 5 [ 36.651795] sd 0:0:0:0: [sda] 3908352 512-byte logical blocks: (2.00 GB/1.86 GiB) [ 36.682780] sd 0:0:0:0: [sda] Write Protect is off [ 36.709971] sd 0:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA [ 36.756973] sda: sda1 what is "doesn't support DPO or FUA" ? I am using Linux kernel 3.3.0. Thanks, Rahul B.