Warnings when insert USB flash

This is - well?
Flash drive work correct
============
FreeBSD lissyara.moskb.local 8.0-CURRENT FreeBSD 8.0-CURRENT #0: Sun Jan 
11 12:17:46 MSK 2009     
lissyara_at_lissyara.moskb.local:/usr/obj/mnt/jabber/DISTR/FreeBSD/src/CURRENT/sys/USB2  
amd64
============
Jan 13 10:51:27 lissyara kernel: ugen4.2: <vendor 0x1976> at usbus4
Jan 13 10:51:27 lissyara kernel: umass1: <vendor 0x1976 Flash Disk, 
class 0/0, rev 1.10/1.00, addr 2> on usbus4
Jan 13 10:51:27 lissyara kernel: umass1:  SCSI over Bulk-Only; quirks = 
0x0000
Jan 13 10:51:28 lissyara kernel: umass1:6:1:-1: Attached to scbus6
Jan 13 10:51:28 lissyara kernel: da4 at umass-sim1 bus 1 target 0 lun 0
Jan 13 10:51:28 lissyara kernel: da4: < Flash Disk 5.00> Removable 
Direct Access SCSI-2 device
Jan 13 10:51:28 lissyara kernel: da4: 1.000MB/s transfers
Jan 13 10:51:28 lissyara kernel: da4: 126MB (259840 512 byte sectors: 
64H 32S/T 126C)
Jan 13 10:51:28 lissyara kernel: (da4:umass-sim1:1:0:0): SYNCHRONIZE 
CACHE(10). CDB: 35 0 0 0 0 0 0 0 0 0
Jan 13 10:51:28 lissyara kernel: (da4:umass-sim1:1:0:0): NOT READY asc:3a,0
Jan 13 10:51:28 lissyara kernel: (da4:umass-sim1:1:0:0): Medium not present
Jan 13 10:51:28 lissyara kernel: (da4:umass-sim1:1:0:0): SYNCHRONIZE 
CACHE(10). CDB: 35 0 0 0 0 0 0 0 0 0
Jan 13 10:51:28 lissyara kernel: (da4:umass-sim1:1:0:0): NOT READY asc:3a,0
Jan 13 10:51:28 lissyara kernel: (da4:umass-sim1:1:0:0): Medium not present
Jan 13 10:51:28 lissyara kernel: (da4:umass-sim1:1:0:0): SYNCHRONIZE 
CACHE(10). CDB: 35 0 0 0 0 0 0 0 0 0
Jan 13 10:51:28 lissyara kernel: (da4:umass-sim1:1:0:0): NOT READY asc:3a,0
Jan 13 10:51:28 lissyara kernel: (da4:umass-sim1:1:0:0): Medium not present
Jan 13 10:51:28 lissyara kernel: (da4:umass-sim1:1:0:0): SYNCHRONIZE 
CACHE(10). CDB: 35 0 0 0 0 0 0 0 0 0
Jan 13 10:51:28 lissyara kernel: (da4:umass-sim1:1:0:0): NOT READY asc:3a,0
Jan 13 10:51:28 lissyara kernel: (da4:umass-sim1:1:0:0): Medium not present
==================
lissyara# mount_msdosfs /dev/da4s1 /mnt/da0/
lissyara# cd /mnt/da0/
lissyara# rm *
lissyara# dd if=/dev/zero of=file bs=1m count=10
10+0 records in
10+0 records out
10485760 bytes transferred in 13.117922 secs (799346 bytes/sec)
lissyara# file file
file: data
lissyara#   

when dettach:
Jan 13 10:54:52 lissyara kernel: (da4:umass-sim1:1:0:0): SYNCHRONIZE 
CACHE(10). CDB: 35 0 0 0 0 0 0 0 0 0
Jan 13 10:54:52 lissyara kernel: (da4:umass-sim1:1:0:0): NOT READY asc:3a,0
Jan 13 10:54:52 lissyara kernel: (da4:umass-sim1:1:0:0): Medium not present
Jan 13 10:54:52 lissyara kernel: (da4:umass-sim1:1:0:0): SYNCHRONIZE 
CACHE(10). CDB: 35 0 0 0 0 0 0 0 0 0
Jan 13 10:54:52 lissyara kernel: (da4:umass-sim1:1:0:0): NOT READY asc:3a,0
Jan 13 10:54:52 lissyara kernel: (da4:umass-sim1:1:0:0): Medium not present
Jan 13 10:54:52 lissyara kernel: (da4:umass-sim1:1:0:0): SYNCHRONIZE 
CACHE(10). CDB: 35 0 0 0 0 0 0 0 0 0
Jan 13 10:54:52 lissyara kernel: (da4:umass-sim1:1:0:0): NOT READY asc:3a,0
Jan 13 10:54:52 lissyara kernel: (da4:umass-sim1:1:0:0): Medium not present
Jan 13 10:54:52 lissyara kernel: (da4:umass-sim1:1:0:0): SYNCHRONIZE 
CACHE(10). CDB: 35 0 0 0 0 0 0 0 0 0
Jan 13 10:54:52 lissyara kernel: (da4:umass-sim1:1:0:0): NOT READY asc:3a,0
Jan 13 10:54:52 lissyara kernel: (da4:umass-sim1:1:0:0): Medium not present
Jan 13 10:54:54 lissyara kernel: umass1: at ushub4, port 2, addr 2 
(disconnected)
Jan 13 10:54:54 lissyara kernel: (da4:umass-sim1:1:0:0): lost device
Jan 13 10:54:54 lissyara kernel: (da4:umass-sim1:1:0:0): removing device 
entry
Jan 13 10:54:54 lissyara kernel: ugen4.2: <vendor 0x1976> at usbus4 
(disconnected)