dd utility: the rescue versions

Apart from the traditional implementations of a Unix dd utility (e. g., one found in the GNU Core Utilities), there are some special versions of it, dedicated for rescuing the data from damaged (badly readable) disks:

1. GNU ddrescue (by Antonio Diaz Diaz);
   seems to be the best choice from these two ones [1, 2];
   there's a GUI log viewer for it (ddrescueview), and also some other helper utilities (ddrutility);
2. dd_rescue (by Kurt Garloff);
   there's also a wrapper script for it called dd_rhelp.

The Debian distribution software archives, starting from version 7.0 ("Wheezy"), have only the GNU ddrescue; you can install it the following way:

# apt-get install gddrescue

The convenient way to use this utility is to make an image (a binary dump) of the whole defective disk (FDD, HDD, CD, DVD etc.) with its help, and then apply data recovery / content extraction programs (e. g., TestDisk) directly to the disk image.

Anyway, regular backups & redundant data storage solutions should save you from data recovery problems :-)

References:

1. Disk drive recovery: ddrescue, dd_rescue, dd_rhelp - System Administration Bits of Knowledge (by John Gilmore)
2. Damaged Hard Disk - CGSecurity

---
Last updated: 2013-12-08

Default Sudo lecture

Here is a standard Sudo lecture, which can be seen at the user's first sudo run time (the following is an unmodified quote extracted from the sudo-$VERSION/plugins/sudoers/check.c source file found in the original sudo 1.8.6p7 source tarball):

#define DEFAULT_LECTURE "\n" \
    "We trust you have received the usual lecture from the local System\n" \
    "Administrator. It usually boils down to these three things:\n\n" \
    "    #1) Respect the privacy of others.\n" \
    "    #2) Think before you type.\n" \
    "    #3) With great power comes great responsibility.\n\n"

References:

1. Sudo Main Page

Few notes about using Canon LBP CAPT laser printers in Linux / *nix

LBP means "laser beam printer" and CAPT does "Canon advanced printing technology".

CAPT devices are some kind of "Windows GDI [Graphics Device Interface] printers". All the RIP [Raster Image Processing] for these printers is done by the driver installed on the host computer, which allows the printer itself to stay relatively "dumb" and inexpensive. They use some proprietary / undocumented protocols called SCoA ("smart compression architecture") and HiSCoA ("high" version, probably) for data compression and communication.

The official Linux CAPT drivers are closed-source with some open-source parts. They support mainly RPM-based (like RHEL, Fedora and openSUSE) and DEB-based (like Debian and Ubuntu) Linux distributions.
CUPS carries out the standard PostScript print processing work, the rest is done by the CAPT driver part itself (and it has some bugs and limitations).
Some instructions about configuring the CAPT printers in Ubuntu can be found here:

• CanonCaptDrv190 - Community Help Wiki
• HardwareSupportComponentsPrinters/CanonPrinters - Community Help Wiki

Note. It's quite interesting that LBP-810 is unofficially supported by the LBP-1120 driver.

AFAIK, currently the most up-to-date version of official Linux CAPT driver is 2.71 (May 2017).

1. Canon South & Southeast Asia ("Issue Number : 0100459601");
2. Canon Australia support website ("Issue Number : 0100459602");
3. Canon Europe support website (it's called "Download: 0100459604", but unfortunately I can't find a more specific generic direct link; please try to search using your printer model).

(Sometimes, some regional sites can have some delays in version release, so it's better to check multiple download links above).

Also, some projects do exist in attempt to develop alternative, free & open source Linux / *NIX drivers with some help of reverse engineering.

1. Canon LBP-810 / LBP-1120 CAPT Linux driver (inactive; there's also a Canon LBP-660 / LBP-460 Linux driver there).
2. Unofficial LBP-3010 CAPT3 Solaris driver at SourceForge (another inactive project).
3. captdriver is a project somewhat inspired by the preceding ones; initially was aimed at LBP-2900, support planned for LBP-810 / LBP-1120 and newer printers like LBP-3000 etc.
   1. GitHub - agalakhov/captdriver: Driver for Canon CAPT printers
   2. GitHub - agalakhov/anticapt: CAPT reverse engineer scratch repo
   3. foo2capt [old versions at SourceForge]
   4. Canon LBP-2900 и другие CAPT-принтеры - ПИШУ ДРАЙВЕР [a discussion in Russian on the LINUX.ORG.RU forum]

---
Last updated: 2017-07-15