The Sicilian defense chess opening: Black fight for center control.

White begins the game with the “king’s pawn” opening by moving pawn to E4. Blacks immidiately responds with the Sicilian defence chess opening and a fight for center control by moving pawn to C5.

The Sicilian defense chess opening: White moves pawn to E4. Black moves pawn to C4.

This move leads to many opening variants, that can create complex positions. The PGN for the Sicilian defence is 1. d4 c5.

The Sicilian defense chess opening.

The dragon variant of Sicilian defense.

One of these variants of the Sicilian defense is the dragon variant. White moves knight to F3. Black immidiately fights for center control and puts pressure on white’s pawn on the E file by moving pawn to D6.

The dragon variant of Sicilian defense: White moves knight to F3. Black moves pawn to D6.

White moves pawn to D4. Black takes it by moving pawn to D4.

The dragon variant of Sicilian defense: White moves pawn to D4. Black takes it by moving pawn to D4.

White takes pawn by moving knight to D4. Black moves knight to C3.

The dragon variant of Sicilian defense: White takes pawn by moving knight to D4. Black moves knight to C3.

White moves knight to C3. Black moves pawn to G6.

The dragon variant of Sicilian defense: White moves knight to C3. Black moves pawn to G6.

These positions looks like a dragon. The PGN for the dragon variant of the Sicilian defense is 1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 g6.

The dragon variant of Sicilian defense.

White might consider moving bishop to E3, bishop to E2, bishop to C4, pwn to G3 or pawn to E4. Black can move bishop to F2, attack white’s knight by moving knight to C6, attack white’s knight by moving pawn to E5 or move pawn to A6.

The dragon variant of Sicilian defense. Possible moves.

The Najdorf variant of Sicilian defense.

Another variant of the Sicilian chess opening is the Najdorf variant, which is the same as the dragon variant with the exception of the last move: White moves knight to C3 as in the dragon variant. Black moves pawn to A6.

The Najdorf variant of Sicilian defense: White moves knight to C3. Black moves pawn to A6.

The PGN of the Najdorf variant is 1. e4 c5 2. Nf3 d6 3. d4 cxd4 4. Nxd4 Nf6 5. Nc3 a6.

The Najdorf variant of Sicilian defense.

White will often move bishop to E3, bishop to F5, bishop to E2, bishop to C4, pawn to H3 or pawn to F3.

The Najdorf variant of Sicilian defense. White’s possible moves.

You might also want to study the Italian game chess opening.

How to upgrade to new minor and major releases of FreeBSD.

New versions of FreeBSD are posted on the front of the homepage.

https://www.freebsd.org/

The supported releases comes with an announcement, release notes, installation instructions, hardware compatibility list, readme, errata and more, which I recommend looking into before upgrading.

https://www.freebsd.org/releases

The homepage of The FreeBSD Project.

Determine the version of FreeBSD kernel and userland.

The built-in freebsd-version utility can determine the installed, running and userland version and patch level of FreeBSD. These should all match.

# freebsd-version -k -r -u

Confirm, that the system can be restored in case of failure.

You might want to ensure, that the system can be restored, if something goes wrong during the upgrade.

If the FreeBSD in question runs on a virtual host, then an offline snapshot at this point in time will make you able to do a quick and easy restore. If the system uses ZFS, then a snapshot can also be used to do a quick restore of one or more datasets. This requires, that the file system and partitions are still working.

In any case you should be able to restore the data from a regular backup repository.

Upgrade FreeBSD to new minor or major version.

FreeBSD can be upgraded to a new minor or major release by using the built-in freebsd-update utility, which can fetch, install and rollback binary updates to the FreeBSD base system. The current patch level does not matter. The upgraded system will have the current patch level.

The update utility will first inspect the system before it will fetch patches, apply patches, fetch files and merges changes in configuration files. The patches and files depends on the internet speed and can take a long time. In the following example FreeBSD is upgraded from 12.1 to 12.2.

# freebsd-update -r 12.2-RELEASE upgrade

When the first step has completed, then the kernel updates can be installed and the system can be rebooted into the installed kernel.

# freebsd-update install
# reboot

The userland updates, which is everything else than the kernel updates, can now be installed. This depends on hardware and can take some time.

# freebsd-update install

If a third party software rebuild is required.

If the upgrade requires, that old shared object files are removed, then third party software, such as packages and ports, needs to be rebuilt. This rebuild can also be done, if you experience problems with packages after the upgrade.

If packages are used, then a static version of pkg can be used to upgrade itself and packages.

# pkg-static install -f pkg
# pkg-static upgrade -f

If ports are used, then portmaster can be used to upgrade the ports, but the recommended practice is, that the package builder poudriere and pkg-static is used. Follow the last procedure, that is given in the manual.

# man portmaster

If a mix is used, then portmaster can be used to rebuild the ports after the packages has been rebuilt. They will overwrite the target files. An example of this could be a desktop computer, which has to use a special port, that replaces a default package, such as a graphics driver.

When third party software has been rebuilt, then the freebsd-update utility can finish the upgrade.

# freebsd-update install

If the running kernel can not be identified.

If the running kernel can not be identified, then a symbolic link can be created as a work-around and the upgrade can be continued. This is a problem, that is related to encryption and ZFS. The issue is described in FreeBSD Forums.

Cannon identify running kernel
# ln -s /bootpool/boot /boot
# freebsd-update install

If the upgrade failed.

If the upgrade failed, then the upgrade can be rolled back by using the rollback feature of the freebsd-update utility.

# freebsd-update rollback
# reboot

If the upgrade was succesful.

If the upgrade was succesful, then the new version and patch level of FreeBSD can be confirmed with the freebsd-version utility. These should all match.

# freebsd-version -k -r -u

You might want to update packages at this point. This would ensure, that your FreeBSD system is completely updated.

The Ruy Lopez chess opening: Start attack immidiately.

A well known opening is the Ruy Lopez chess opening. If you do not know much about openings, this one might be worth studying first. I will go through each move, show the final positions of the chess opening and then round off with possible moves from that.

White starts an attack immidiately with “king’s pawn” by moving pawn to E4.

Black mirrors white’s move and moves pawn to D5. White moves knight to F3.

Black moves knight to C3. White attacks by moving bishop to B5.

White has taken control of the center of the board and has prepared to castle at the same time. The PGN for the Ruy Lopez chess opening is 1. e4 e5 2. Nf3 Nc6 3. Bb5.

The Ruy Lopez chess opening.

Blacks might consider attacking white’s bishop by moving pawn to A3. Black might also consider other options.

The Ruy Lopez chess opening: Possible moves.

You might also want to study the Sicilian defense chess opening.