Actually, rather than calling it "force-erase" it's better off being called as trickery.
From the Wikipedia article about DVD+RW,
DVD+RW supports random write access, which means that data can be added and removed without erasing the whole disc and starting over (up to about 1000 times).
While that 'add and remove without erasing the whole disc' thing sounds great, what if you want to erase the disc securely?
Try erasing it with say, K3B, and it'll bail out saying erasing will be done in the background; meaning that if you have 4.4GB of stuff on the disc and you overwrite it with a smaller amount, the old data is still there - Old data which you want to get rid of for some reason (security is a good excuse).
The simplest way of totally erasing a DVD+RW is by writing a 4.4GB ISO which has nothing but 0's in it.
So, from a terminal create the above mentioned disc image using dd.
dd if=/dev/zero of=/tmp/BlankISO.iso bs=1000000 count=4700
Now you just have to burn this ISO file onto your DVD+RW and you have a completely empty disc.
P.S : Blanking a DVD+RW actually defeats the purpose of using a DVD+RW but sometimes you just can't help it.
Cheers!
This HOWTO assumes that you're going to perform a fresh installation of Slackware 12. So lets start :
In this howto, i install Slackware on 3 sofware RAID0 configurations using mdadm. One for /, one for /home and another one for /mnt/extras.
Boot up the Slackware DVD and log in as root.
Use cfdisk to create the partitions on the harddrives :
The partitioning scheme for my 2 x 80GB SATA harddrives :
/dev/sda :
sda1 Primary Linux ext3 139.83
sda2 Primary Linux raid autodetect 5116.13
sda3 Primary Linux raid autodetect 59411.20
sda4 Primary Linux raid autodetect 15356.60
/dev/sdb :
sdb1 Primary Linux raid autodetect 5116.13
sdb2 Primary Linux raid autodetect 59411.20
sdb3 Primary Linux raid autodetect 15356.60
sda1 is a 140MB partition dedicated to hold the kernel image as well as the bootloader since no bootloader i know of can boot off a software RAID 0 array.
Build your arrays with Multiple Devices Admin (mdadm) program ( level=0 : Striped/RAID0, level=1 : Mirrorred/RAID1, level=4/5/6/10, man mdadm for more help on this )
- mdadm --create /dev/md0 --level=0 --raid-devices=2 /dev/sda2 /dev/sdb1 # for root
- mdadm --create /dev/md1 --level=0 --raid-devices=2 /dev/sda3 /dev/sdb2 # for home
- mdadm --create /dev/md2 --level=0 --raid-devices=2 /dev/sda4 /dev/sdb3 # for anything else ;)
Now fire up the installation as usual (# setup)
Now, when it comes to selecting partitions, pick /dev/md0 as the target for "/" (root)
As you progress in the installer, create the mountpoints :
- "/home" for the device "/dev/md1"
- "/boot" for the bootloader on "/dev/sda1"
- "/mnt/extras" or anything else for "/dev/md2" [this step is optional]
Install everything as you normally would.
Now we mount Slackware (/dev/md0) and the boot partition and chroot into the system
- mkdir /mnt/md0
- mount /dev/md0 /mnt/md0
- mount /dev/sda1 /mnt/md0/boot
- chroot /dev/md0
Now we are in the OS installed on our software RAID array. Next we mount the Slackware DVD, install and setup GRUB (because i prefer GRUB to LILO ;)
- mount /dev/cdrom /mnt/cdrom
- cd /mnt/cdrom/extra/grub
- installpkg grub*.tgz
- grub-install --root-directory=/boot /dev/sda # WARNING : GRUB goes into sda's MBR
- cd /boot/boot/grub
- touch menu.lst
Create boot entries in menu.lst for GRUB to boot (# nano /boot/boot/grub/menu.lst)
My /boot/boot/grub/menu.lst looks like this :
timeout 10
title Slackware Linux 12.0
root (hd0,0)
kernel /vmlinuz root=/dev/md0 ro
boot
Save & Close.
Just to make sure that fstab mounts the right arrays in the right places, its better to take a look at it is in /etc before we boot into the system (# nano /etc/fstab)
My /etc/fstab looks something like this (Your's probably should look something similar to this ) :
/dev/md0 / ext3 defaults 1 1
/dev/sda1 /boot ext3 defaults 1 2
/dev/md1 /home ext3 defaults 1 1
just type 'exit' to get out of the system and into the DVD, unmount all the drives and reboot.
- exit
- umount /dev/sda1
- umount /dev/md0
- umount /dev/md1
- umount /dev/md2
- reboot
Now if all went well, your Slackware should boot normally that too from a RAID array! ;)
Enjoy !
Installing Apache HTTP Server
- tar zxvf httpd.tar.gz
- cd httpd
- ./configure --prefix=/usr/local/apache --enable-mods-shared=most --enable-deflate
- make
- make install
- echo "/usr/local/apache/lib" >> /etc/ld.so.conf
- ldconfig
For Apache to run at boot :
- echo "/usr/local/apache/bin/apachectl start" >> /etc/rc.d/rc.local
Installing PHP 5
- tar zxvf php.tar.gz
- cd php
- ./configure --prefix=/usr/local --with-config-file-path=/etc --with-apxs2=/usr/local/apache/bin/apxs --disable-debug --enable-memory-limit --enable-inline-optimization --enable-magic-quotes --enable-mbstring --enable-track-vars --enable-xml --with-dom --with-xml --enable-sockets --with-zlib --with-gettext --with-pear
- make
- make install
- cp php.ini-recommended /etc/php.ini
Edit /etc/php.ini and do the following:
- change "short_open_tag" to On
- change include_path to ".:/usr/local/lib/php"
Edit /usr/local/apache/conf/httpd.conf and do the following:
- add "LoadModule php5_module modules/libphp5.so"
- add "index.php" to DirectoryIndex
Now, get back to your terminal and just run the following.
- echo "application/x-httpd-php php" >> /usr/local/apache/conf/mime.types
- sudo /usr/local/apache/bin/apachectl start
Summer, 2008
Blissfully unaware about Hardware Compatibility Lists in driver pages, i finally got myself a USB web cam. It was this little thing i thought would work without hassle. >>
Looks like i was wrong. A `lsusb` output on my Debian GNU/Linux box and this was what i got :
$lsusb
093a:2460 Pixart Imaging, CIF Single Chip
Looking all good, i headed down to Google to search for the vendor ID. I ended up with this (http://mxhaard.free.fr/download.html) page and found out that my cam was supported by the spca5xx drivers. Downloaded the tarball from the same site, wasted a couple of hours downloading hell lot of dependencies for the compilation and finally it compiled. ;)
It just didn't work no matter what. The cam was sitting there literally for months together until i found another blog deeply hidden in Google in which the guy had the same problem as mine and thank heavens he had a workaround too.
So this is what i had to do :
$ cd /path/to/the/tarball/
$ tar xvf gspcav1-20071224.tar.gz
$ cd gspca/modules/gspca/Pixart/
Once there, you need to edit a file called pac207.h
In Line 137, replace if(id[0]!=0x27) with if(id[0]!=0x27 || id[1]!=0x08)
So you'll end up with this :
....
PDEBUG(2, " Pixart Sensor ID 0x%02X Chips ID 0x%02X !!\n", id[0],
id[1]);
if(id[0]!=0x27 || id[1]!=0x08)
return -ENODEV;
return 0;
....
Well, that's pretty much it. Just save the file, close and rebuild it with "make" and "make install" as root.
Plug in the cam and you'll see some messages appear in `dmesg | tail` if your webcam was successfully detected and gspca driver was loaded right and yes the cam was working!
P.S : If your kernel doesn't auto-load modules, just do a modprobe gspca
