NSLU2-Linux
view · edit · print · history

How can I use the slug with just a USB flash memory key - I don't want to attach a hard disk

This page relates to Unslung. Other systems (OpenSlug, Debian) dont have the complexity described here.

The slug has two USB ports marked as:

Disk 1
Disk 2/Flash

The Linksys documentation specifically says: do not plug a USB flash memory key into the "Disk 1" port. You are instructed by Linksys to plug it into the "Disk 2/Flash" port. The Unslung doco however indicates you should format the hard disk (your USB flash memory key) before you do the firmware upgrade and validate its functionality. You plug the USB flash memory key into the "Disk 1" port as recommended and find you can't format it with the Linksys firmware. Now what?

The fundamental problem is not really with USB ports, it is that the native Linksys firmware will not permit any device smaller than 10 Gigabytes in size to be formatted. Therefore, the flash device has to be formatted later using the Unslung firmware. Follow all the Unslung steps as documented and at this step format the USB flash memory key using the web interface. Versions prior to 6.8-beta may require that the formatting be done in the Disk 1 port. As of 6.8-beta, the disk can be plugged into either port and can be succesfully formatted.

Note: bcrowell tried formatting a 16 Gb flash drive using the Linksys web interface, and it didn't work, so apparently the size <10 Gb isn't the issue.

"4) Identify which drive you wish you "unsling", and plug it in. Wait a minute or two while the disk is mounted.
If the disk has not been previously formatted on the NSLU2, then now is the time to do that. Make sure that the drive is recognized in the web interface."

The web interface is a bit vague about whether it has performed a successful format, so give it a minute or so, switch to the Home page and then return to the "Administration-->Disk" page to refresh it. It should now show "Formatted" for the disk you just finished formatting, and "Not Installed" for the other one. If the first format results in a FAT/Win32 file system being displayed for the drive in the Web UI, power down, power back up, and do the format again, after which it should show ext3 file system (assuming your flash drive is either 1GB or larger, OR is on Drive 1, or both -- see below).

It's worth checking out http://www.nslu2-linux.org/wiki/Unslung/Ext3flash, to cut down on unnecessary writes to the flash disk, prolonging its life.

Notes:

1) The USB flash memory key must be 256MB (or bigger) for Unslung 5.5, and 512MB (or bigger) for Unslung 6.8. (dustinemptyspace wrote: I had problems also with the 256Mb and I had to prepare the flash manually: http://www.nslu2-linux.org/wiki/HowTo/UseAMemoryStickAsMainDrive)

2) Once you are up and running the ports are mapped to these two directories:

Disk 1 ---> /share/hdd/.. (your USB flash memory key)
Disk 2/Flash ---> /share/flash/.. (nothing attached)

This is confusing as you are now using a USB flash memory key for the hard disk -> ie /share/hdd/.. but /share/flash/.. is unused.

3) This FAQ originally referred to 3.x Unslung software... some of the above has been updated to refer to 6.8-beta software.

4) Background info credited to Rod Whitby:

Linksys treats 10GB or larger as disks (ext3) and assumes that devices less than 10GB are flash (VFAT). In addition, Linksys only allows flash on disk2. For Unslung 5.5, the Unslung firmware treats 1GB or larger as disk (ext3), and less than 1GB as flash (VFAT), unless the flash is on disk1, in which case it is treated as a very small ext3 disk. For Unslung 6.8-beta, there is no distinction made - all devices are treated as disks, regardless of size or port.

For the flash disk, 256MB is the minimum for Unslung 5.5, and 512MB is the minimum for Unslung 6.8-beta. This minimum is due to the way that the Linksys software partitions devices. In the case of Unslung 6.8-beta, the standard Linksys formatting procedure will allocate 128MB of space for swap, 128MB of space for the "conf" partition, and the remainder is available for the root filesystem and your data. Whether or not you need larger depends on how many packages you are going to load.

view · edit · print · history · Last edited by bcrowell.
Based on work by Stephen Hippisley-Cox, Phil Endecott, mwester, Anonymous, dustinemptyspace, and tman.
Originally by tman.
Page last modified on December 27, 2007, at 11:28 PM