I made a usb cable for my N800 which installed OS2008, it can access flask disk and usb keyboard successfully. But it can not access usb portable hard disk which has a separate power supply. A message "can not access file system" popped up.It seems usb of drivers operation system doesn't support this kind of device.

Can the OS be hacked to support USB portable hard disk? Wish somebody figure it out.

There are a lot of threads trying to solve this issue with varying levels of success. the main issue seems to be the way the kernel is compiled (ie options set).

I am really looking forward to the when I can carry come usb devices to use with my tablet (a little gamepad would be great for emulators)

Two Wiki pages.

1. N810_MicroB_to_MiniB_Plus_easy_OTG_host_mode

2. USB_CDROM_Drive

It does support portable hard drives with the following two caveats:

1. It must be DOS/MBR partitioned and use a FAT filesystem (or if you load the modules, ext2/3).

2. You must use a powered hub, or the disk itself must not request more than a very small amount of power. Most disks that can be powered via USB need too much - even microdrive based flash drives may have problems. Many with external supplies request more than they may need, but the n810 will reject anything that goes over-budget which is 200ma.

With a hub I could mount iPods, WD MyBook (1/2 Tb!), and by adding isofs/udf/cdrom/sr_mod and issuing a mount command, a CD/DVD writer.


There are some USB portable hard drives with internal batteries (I don't have one but something like:http://www.usbgear.com/computer_cabl...77%2C140%2C161)

Thanks you very much, all of you!
My usb hub has a separate power supply, so I think the power is not the problem The OS of my PC is windows xp, I use it's tool disk manager to format my hard disk to FAT32 type, Is that right?
I don't know wether it has be Dos/MBR formatted.

Dunno about this, but I plugged my external USB HD enclosure (40G HD in it) into the n800 through the OTG cable I made up and it came up with the usual "not supported" message and then opened in file manager just fine. It was a little slow I thought, but worked fine otherwise (yes, drive is pretty full :-).

Just for fun I picked up a USB keyboard at the thrift store and plugged that in the same way and after the "no supported" message it worked fine too.

Neither of these required the power injector I made up. HD enclosure does have it's own PS built in, FWIW.

Only "problem" with the USB Keyboard is that the LEDs didn't work otherwise it was fine. According to usbview on this box, the keyboard only needs 100 mA Max and from what I can tell from my reading, the N800 will supply 200 mA(?!?), so I don't know. Just plugged it into this machine and the LEDs work fine...

Forgot to mention that all the partitions on that HD are ext3...