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Image of Modern Operating Systems (3rd Edition)
Image of Linux Kernel Development (3rd Edition)
Image of Advanced Programming in the UNIX Environment, Second Edition (Addison-Wesley Professional Computing Series)
Image of Android Wireless Application Development

Copy DVD to Image File

On Linux, /dev/cdrom, /dev/dvd and /dev/cdrw are usually just symbolic links to /dev/sr0 or some other optical disc device. The following example shows one way to copy a a CD-ROM or DVD to an ISO file. dd if=/dev/dvd of=dvd.iso This mostly works, but sometimes a few extra NULL blocks are copied which will cause the DVD checksum not match the ISO image file checksum. The following will create an image of a DVD while ensuring that the image will have exactly the same checksum as the DVD itself: # COUNT=$(isoinfo -d -i /dev/cdrom) # dd if=/dev/dvd bs=2048 count=$COUNT conv=notrunc,noerror >

GRUB2 Sleep

So how do you make GRUB2 sleep for a number of seconds? Try out the following three command strings from the GRUB2 prompt: Type sleep 10, and nothing appears on the screen for 10 seconds. Type sleep -v 10, and you will see the number of seconds displayed counting down from 10 to 0. Type sleep -i -v10, and you can press the ESCAPE key at any time to return to your main boot menu. As you can see there are a number of useful option to the GRUB2 sleep command. Here is the formal syntax for the sleep command:

extensions.gnome.org alpha

Jasper St. Pierre just announced the alpha test of extensions.gnome.org: We’re happy to announce that extensions.gnome.org is now in public alpha testing at: https://extensions.gnome.org If you have GNOME Shell 3.2 on your system, you should be able to install extensions from the website via your browser. This uses the “GNOME Shell Integration” browser plugin which is likely already installed on your system if you have GNOME 3.2. The plugin only works with Firefox currently – see “Known Bugs” below. We’ve seeded the site with a small set of extensions, including the extensions from gnome-shell-extensions. If you are the author of

Sprintf Portability and Leading Zeros

On some platforms, code such as the following can be used to output a string with leading zeros left padded to a length of 4. sprintf(*str, “%04s”, *pstr); This works on AIX for example. However if the same code is compiled on Linux using gcc, it outputs leading spaces, padded to a length of 4, instead of leading zeros. There is no simple way to fix this behavior. This particular usage of leading zero padding with the string format is explicitly undefined in the various C standards. What is outputted depends on a platform’s libraries rather than the compiler. As

The Strange Birth and Long Life of Unix

The December 2011 issue of the IEEE Spectum magazine has an interesting article on Unix by Warren Toomey. It includes some material on the origins and evolution of Unix which I have never come across before. End runs around AT&T’s lawyers indeed became the norm—even at Bell Labs. For example, between the release of the sixth edition of Unix in 1975 and the seventh edition in 1979, Thompson collected dozens of important bug fixes to the system, coming both from within and outside of Bell Labs. He wanted these to filter out to the existing Unix user base, but the