TQ2440 sd卡读取问题

1.
当sd卡插上时，用df查看如下：

[root@EmbedSky /]# df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/root               125952     79368     46584  63% /
tmpfs                    30068         0     30068   0% /tmp
tmpfs                    30068         0     30068   0% /dev
/dev/mmcblk0p1         3878912     22720   3856192   1% /sddisk

进去目录内容如下：
[root@EmbedSky /sddisk]# ls
ESupMonitor.db        private               sqlite3.sh
ESupMonitorBackup.db  sdcard
libsqlite3.so.0       sqlite3

2.拔掉sd卡，用df查看如下：
[root@EmbedSky /sddisk]# df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/root               125952     79368     46584  63% /
tmpfs                    30068         0     30068   0% /tmp
tmpfs                    30068         0     30068   0% /dev
/dev/mmcblk0p1         3878912     22720   3856192   1% /sddisk

进去目录内容如下：
[root@EmbedSky /sddisk]# ls
FAT: Directory bread(block 8192) failed
FAT: Directory bread(block 8193) failed
FAT: Directory bread(block 8194) failed
FAT: Directory bread(block 8195) failed
FAT: Directory bread(block 8196) failed
FAT: Directory bread(block 8197) failed
FAT: Directory bread(block 8198) failed
FAT: Directory bread(block 8199) failed
FAT: Directory bread(block 8200) failed
FAT: Directory bread(block 8201) failed
FAT: Directory bread(block 8202) failed
FAT: Directory bread(block 8203) failed
FAT: Directory bread(block 8204) failed
FAT: Directory bread(block 8205) failed
FAT: Directory bread(block 8206) failed
FAT: Directory bread(block 8207) failed
FAT: Directory bread(block 8208) failed
FAT: Directory bread(block 8209) failed
FAT: Directory bread(block 8210) failed
FAT: Directory bread(block 8211) failed
FAT: Directory bread(block 8212) failed
FAT: Directory bread(block 8213) failed
FAT: Directory bread(block 8214) failed
FAT: Directory bread(block 8215) failed
FAT: Directory bread(block 8216) failed
FAT: Directory bread(block 8217) failed
FAT: Directory bread(block 8218) failed
FAT: Directory bread(block 8219) failed
FAT: Directory bread(block 8220) failed
FAT: Directory bread(block 8221) failed
FAT: Directory bread(block 8222) failed
FAT: Directory bread(block 8223) failed
FAT: Directory bread(block 8224) failed
FAT: Directory bread(block 8225) failed
FAT: Directory bread(block 8226) failed
FAT: Directory bread(block 8227) failed
FAT: Directory bread(block 8228) failed
FAT: Directory bread(block 8229) failed
FAT: Directory bread(block 8230) failed
FAT: Directory bread(block 8231) failed
FAT: Directory bread(block 8232) failed
FAT: Directory bread(block 8233) failed
FAT: Directory bread(block 8234) failed
FAT: Directory bread(block 8235) failed
FAT: Directory bread(block 8236) failed
FAT: Directory bread(block 8237) failed
FAT: Directory bread(block 8238) failed
FAT: Directory bread(block 8239) failed
FAT: Directory bread(block 8240) failed
FAT: Directory bread(block 8241) failed
FAT: Directory bread(block 8242) failed
FAT: Directory bread(block 8243) failed
FAT: Directory bread(block 8244) failed
FAT: Directory bread(block 8245) failed
FAT: Directory bread(block 8246) failed
FAT: Directory bread(block 8247) failed
FAT: Directory bread(block 8248) failed
FAT: Directory bread(block 8249) failed
FAT: Directory bread(block 8250) failed
FAT: Directory bread(block 8251) failed
FAT: Directory bread(block 8252) failed
FAT: Directory bread(block 8253) failed
FAT: Directory bread(block 8254) failed
FAT: Directory bread(block 8255) failed
[root@EmbedSky /sddisk]#

问题：为什么拔掉了，df查看还有sd卡还有内容

本来想通过df |grep /sddisk 做一个判断sd卡是否有被拔掉的程序?
现在df命令不给力，TQ2440系统更不给力。烦！

求坛主帮忙下，本人就是要把历史数据放在sd卡上，但是sd卡有时候没插上，程序就出错。

所以我现在想弄个程序判断sd卡是否有插上。。。

挂载上去后 用umount /sddisk
然后在用df查看正常。

问下，现在sd卡没拔出去。我要怎样才能再挂载上去。

挂载是这样可以了mount -t vfat /dev/mmcblk0p1  /sddisk/

sd卡好像不通过umount ,就会出现如下错误：

[root@EmbedSky /sddisk]# ls
FAT: Directory bread(block 8192) failed
FAT: Directory bread(block 8193) failed
FAT: Directory bread(block 8194) failed
FAT: Directory bread(block 8195) failed
FAT: Directory bread(block 8196) failed

亲，在TQ2440配套的文件系统里面已经做了插SD卡自动挂载，拔掉SD卡自动卸载的功能。判断SD卡是否在可以通过查看/dev下的mmcblkxxx设备来查看SD卡是否插入。至于拔卡之后出现那个错误信息算是正常的了，因为拔卡的动作永远都要快于系统卸载卡的动作，除非你手动卸载SD卡。

亚瑟王 发表于 2012-3-5 11:05
亲，在TQ2440配套的文件系统里面已经做了插SD卡自动挂载，拔掉SD卡自动卸载的功能。判断SD卡是否在可以通过 ...

哦哦，我自己都知道要通过那个挂载，但是我没动手去测试，先自我检讨下！

亚瑟王 发表于 2012-3-5 11:05
亲，在TQ2440配套的文件系统里面已经做了插SD卡自动挂载，拔掉SD卡自动卸载的功能。判断SD卡是否在可以通过 ...

问下亚瑟王，那个我一直问的那个TQ2440摄像头有底纹怎么处理，你说有软件可以测试，那个软件哪里，能否给个链接！

明天上传。