Blog Amain » debian

Partitions on a loop device ( /dev/loop0p0, /dev/loop0p1, … )

Amain — Wed, 21 Apr 2010 11:38:11 +0000

Add the following kernel boot option to the kernel line in grub’s menu.lst and reboot ( I’m not sure which one does the trick ):
```
loop.max_part=63 max_part=63
```
Create a sparse disk image file ( 40 GB reserved, 0 bytes on disk )
```
dd if=/dev/zero of=fs.image bs=1024 seek=40000000 count=0
```
Initialize a new loop device ( /dev/loop0 )
```
losetup -f fs.image
```
Create a partition table, for example 2 partitions. A 4 GB swap(loop0p1) and a root filesystem(loop0p2) containing the remaining space.
```
fdisk /dev/loop0
```
Reread partition table for /dev/loop0. Nodes /dev/loop0p1, /dev/loop0p2, etc are created.
```
sudo blockdev --rereadpt /dev/loop0
```

Create filesystems

mkswap /dev/loop0p1
mkfs.ext3 /dev/loop0p2

Mount the filesystem and use debootstrap or any other method to create a file system. Don’t forget to install or copy grub to it.
```
mkdir fs
sudo mount /dev/loop0p2 fs
```
Install grub
grub
grub> device (hd0) /dev/loop0
grub> root (hd0,1)
grub> setup (hd0)

Wake-on-LAN (wol)

Amain — Thu, 03 Dec 2009 23:35:06 +0000

On the to-be-woken-up computer make sure to enable ACPI/APM (S3/STR) and Wake-On-Lan(WOL) in the BIOS and add in /etc/network/interfaces:

post-up /usr/sbin/ethtool -s eth0 wol g
post-down /usr/sbin/ethtool -s eth0 wol g

Write down the MAC-ADDRESS. Powerdown the computer. Only when the computer is powered down to S3 or STR(Suspend to ram), the computer can be woken up. A sudden power-failure might mess with everything so the computer might not respond then to WOL requests. For STR some additional action are necessary, because STR in Linux might/will totaly power-off the ethernet device. See this link for more info on that subject.

On another computer install a wake-on-lan package:

dpkg -i wakeonlan

and wake up the sleeping computer:

wakeonlan MAC-ADDRESS

note: create a small shell script in for example ~/bin/wol_dev.sh to make life easier and to not forget the MAC-ADDRESS:

#!/bin/sh
#
# Wake on lan server: dev
#
# dev eth0 00:02:44:57:dc:33
# dev eth1 00:10:4b:0e:ce:13
 
wakeonlan 00:02:44:57:dc:33

That’s all!

Links:

Debian on OpenWRT supported routers (ASUS WL-500gd and compatible)

Amain — Tue, 24 Mar 2009 17:00:59 +0000

I created a very nice project which turns an OpenWRT supported router into an embedded device running a full Debian ARM GNU/Linux distribution instead of the default small Busybox/uLibc based OpenWRT distribution. I called the project DebWRT. It took me a lot of time to make all the pieces work together.

I tested everything on an ASUS WL-500GD and a user has reported that it also works on an ASUS WL-500G Premium v.1. The project contains an customised OpenWRT kernel (2.4 or 2.6) (which will boot from an USB-disk or USB-stick) and an Debian Etch GNU/Linux pre-installed base image, which includes a lot of customisation. The image contains pre-configured out-of-the-box enabled networking, firewall, webserver, Samba server, and more.

Unfortunately there are some issues(see the project pages) with the b43 wireless driver and the 2.6 kernel, so for that reason I created also a 2.4 kernel image with full wireless support.

See the project website http://www.debwrt.net/ for more information. Also if you are interested in how to compile a custom OpenWRT kernel, or how to create an Debian base root filesystem for an embedded device from scratch.