开发板启动问题

s7703179

Looking up port of RPC 100003/2 on 192.168.1.240
Looking up port of RPC 100005/1 on 192.168.1.240
Root-NFS:Server returned error -5 while mounting /nfsroot
VFS:Unable to mount root fs via NFS,trying floppy.
VFS:Cannot open root device "nfs" or unknown-block(2.0)
Please append a correct "root=" boot option;here are the available partitions:
1f00                      256 mtdblock0 (driver?)
1f01                    3840 mtdblock1 (driver?)
1f02                  81920 mtdblock2 (driver?)
1f03                176128 mtdblock3 (driver?)
b300             1968128 mmcblk0 driver:mmcblk
Kernerl panic - not syncing: VFS: Unable to mount root fs on unknown-block(2,0)

minicom  启动  跑到这步就停了，虚拟机装的ubuntu系统，Vmware网络连接选Bridged了， 板子IP 是 192.168.1.20 ，电脑IP是 192.168.1.240, /etc/exports 修改了 /nfsroot *(rw,sync,no_root_squash)
不知道哪的问题了  ，

bootargs 设置是  bootargs=root=/dev/nfs nfsroot=192.168.1.240:/nfsroot ip=192.168.1.20 console=ttySAC0,115200"

noiplee

NFS服务有启动否？