The Answer Gang

By Jim Dennis, Karl-Heinz Herrmann, Breen, Chris, and... (meet the Gang) ... the Editors of Linux Gazette... and You!

---

/dev/ub

From

Answered By Frodo

A few days ago, I changed to kernel 2.6.9 on one of my machines and suddenly none of the sd devices were made for my usb harddisks. Turned out, 2.6.9 now uses the /dev/ub/ structure instead... took me a while to figure that one out... lol

Low Performance USB Block driver (BLK_DEV_UB)

It does not seem to be enabled by default... guess I accidentally enabled it, but it actually does seem to work a bit better with some of my devices, when using USB 2.0 instead of USB 1.1

(some external harddisks seem to not be happy with the way Linux used to handle USB 2.0)

[Heather] ooh so it isn't merely cosmetic. ok.

am trying to find out, what exactly happened

what I do know, is that the "old" way did a usb to scsi thingie...

 config BLK_DEV_UB
 	tristate "Low Performance USB Block driver"
 	depends on USB
 	help
 	  This driver supports certain USB attached storage devices
 	  such as flash keys.
 	  If unsure, say N.

might just make it a lil warning:

"If you happen to enable BLK_DEV_UB, your USB attached storage devices will no longer be known as /dev/sdxn (where x is a letter and n a number), but as /dev/ub/x/partn."

[Jimmy]

https://www.linux-usb.org/usb2.html

From: https://hulllug.principalhosting.net/archive/index.php/t-48985.html

> You're using the UB driver. Does it work if you turn that off and use the
> usb-storage driver instead?
Damn, you are right - this is a new driver...
I didn't notice that, i did rely on hotplug to load the correct modules.
Removed the ub driver and everything is fine now.
That means - just unloadin ub and loading usb-storage didn't work.
I had to remove it from the kernel config and rebuild the modules. Actually
usb-storage was the only module being rebuilt. Looks like usb-storage's
functionality is different if ub is built."

btw, about the linux-usb.org link... I know that page... but there seem to be quite a few external hard disks (WD, for instance) and cases for hard disks, that do not work too well with linux' usb2.0 driver afterall...

quite probably the fault of those devices... but it stinks anyway :)

[Heather] having to rebuild usb-storage? aw man, that does suck. can you keep both forms of it around or does it subtly affect other things too? (not to be tested with usb data you care about mind..)

nah, it seems to replace part of the usb stuff...

(well - usb-storage)

the rest seems unaffected

[Heather] A bit of binary diff on the other usb modules might be in order :/

Now I know where the device files are, I have no problem with it... it "just works" G

---

This page edited and maintained by the Editors of Linux Gazette
HTML script maintained by Heather Stern of Starshine Technical Services, https://www.starshine.org/

---