Archive for the ‘Linux’ Category
Sierra Wireless mobile broadband modem differences
As I was recently signing up for Sprint’s mobile broadband solution, I was presented with the choice between the Sierra Wireless USB 598 modem and the older Sierra Wireless Compass 597 USB. I couldn’t find any explanation of the differences between them, so here’s what I’ve found so far:
- The 598 is prettier with bright, attractive LEDs.
- The 598 supports higher capacity micro-SD cards
- The 598 comes with a longer USB extension cable and a laptop clip to attach the modem to the top of your laptop screen. (I miss this quite a bit, surprisingly)
- The 598 has a power saving mode that turns off the modem when the Sprint Smartview application isn’t running (OS X)
- I can’t get the USB disk feature to work at all with a 2GB micro-SD card on my 597, though I suppose mine could be broken
In the end I went with the 597 because of the out-of-the-box Ubuntu support in 8.10, but the 598 is better for non-Linux use. Of course, I get the impression that Sprint won’t be carrying the 597 for much longer, so the point may be moot…
So far I’ve gotten excellent customer support from Sprint. I’m really not used to such kind, helpful and competent assistance from a mobile company, so I felt like I should mention it.
Simple encrypted disk images in Linux
The Linux kernel supports encrypted loop images via the cryptoloop driver, so you can use losetup(8) to create simple encrypted loop devices for those situation when cryptsetup/LUKS/device-mapper is unavailable or too complicated.
You’ll need the following modules loaded (or compiled in):
- loop
- cryptoloop
- twofish (or whatever algorithm you prefer)
First you’ll need to allocate the file:
# dd if=/dev/zero of=<file> bs=1k count=<fs-size-in-kilobytes>
After that, you can ask losetup to loop it to the first free loop device and report back which it chose:
# losetup -e twofish -f -s <file>
The first time out you’ll want to format the device (e.g. mke2fs -j /dev/loop0), after that it’s just a matter of mounting (mount /dev/loop0 /mnt). After you’re done you can use losetup to close the file and remove the device:
# losetup -d /dev/loop0
An important note about this method is that there is no sort of password validation. Whatever password you enter will be used by the encryption algorithm. That means if you enter the incorrect password then you’ll just read (or worse: write) a bunch of garbled data from the device.
tech stuff. 