Force Virtualbox Display in Fullscreen

I have a dual display setup with virtualbox.  In fullscreen I found that virtualbox would switched onto my smaller display.

This can be adjusted.

1) Switch to fullscreen with Virtualbox

2) Use the combination of your "host" key + "home" key. (right-ctrl + home) in my case.

3) Go to the "view" menu item -> "virtual screen"

4) Select the appropriate monitor.

5) If the size of your display varies,  you will have to go out of fullscreen and back into fullscreen to re-adjust the workspace to the correct size.

yum crashed with python import error - fixed corrupted rpm database

I ran into an interesting error while trying to find out, which repository one of my installed packages came from.  Before we proceed, let me explain that I had need to use the "repoquery" utility which is part of the "yum-utils" package.  I proceeded to install this one as I did not yet have it.  The installation worked perfectly well and did not install any dependencies.

# yum install yum-utils -y

Using the repoquery command, I attempted to query which repo my php53 package came from:

$ repoquery -i php53

Instead of getting the information I wanted, the script crashed with the following error:

File "/usr/bin/repoquery", line 38, in

from yum.i18n import to_unicode

cannot import name to_unicode

Googling around, many blog posts and site talked about the yum installation being broken.  That may well be, but I decided to see if maybe there was something a bit simpler at play here.  First I needed to find out which yum packages are already installed on this system:

# rpm -qa | grep -i yum

yum-fastestmirror-1.1.16-16.el5.centos
yum-3.2.22-37.el5.centos
yum-updatesd-0.9-2.el5
yum-utils-1.1.16-16.el5.centos
yum-metadata-parser-1.1.2-2.el5

NOTE: The listed version numbers do not reflect the original numbers I had on my system.  I went ahead and attempted to update all of the above listed packages:

# yum update yum yum-fastestmirror yum-updatesd yum-metadata-parser

Yum only found that yum and yum-fastestmirror needed to be updated.  I proceeded with the update.

After the update, the repoquery command started working perfectly well.  However, a completely unrelated problem occurred which I will discuss very briefly.

# repoquery -i php53

Instead of getting a nice listing of information from the RPM database, I received an error message saying the database was corrupted.  The next step then was to rebuild the dabase.  

The database files are located in "/var/lib/rpm" and are named __db.001 __db.002 etc... etc...

Delete those files:

# rm -f /var/lib/rpm/__db*

Rebuild the database:

# rpm -vv --rebuilddb

Once completed, I tried the repoquery command once again:

# repoquery -i php53

Name        : php53
Version     : 5.3.3
Release     : 1.el5_7.6
Architecture: x86_64
Size        : 3591477
Packager    : None
Group       : Development/Languages
URL         : http://www.php.net/
Repository  : updates
Summary     : PHP scripting language for creating dynamic web sites
Description :
PHP is an HTML-embedded scripting language. PHP attempts to make it
easy for developers to write dynamically generated webpages. PHP also
offers built-in database integration for several commercial and
non-commercial database management systems, so writing a
database-enabled webpage with PHP is fairly simple. The most common
use of PHP coding is probably as a replacement for CGI scripts.

The php package contains the module which adds support for the PHP
language to Apache HTTP Server.

Convert Blocks to Bytes

Very easily 

=========== CONVERT FROM BYTES TO BLOCKS =========== 

For example:

100 Megabytes = 1024 x 1024 x 100

---------------------------------

1 Megabyte = 1024 x 1024 x 1

1 Kilobyte = 1024 x 1

1 Byte = 1

A block is a set quantity of bytes. For example, a mounted partition could have blocks of 4096 bytes or 4k.

Typically however, quotas will have a block size of 1024 bytes ( 1k ).

To calculate the quantity of blocks for quotas you should allocate blocks using the following formula:

Allocate 100Mb of space to a user:

1024 x 1024 x 100 = 104,857,600 (in bytes) = 100Mb

Divide the number of bytes by the block size:

Block size of 4096: 104,857,600 / 4096 = 25,600 blocks

Block size of 1024: 104,857,600 / 1024 = 102,400 blocks

25,600  blocks = 100Mb if your block size is 4096 (unlikely for quotas)

102,400 blocks = 100mb if your block size is 1024

=========== CONVERT FROM BLOCKS TO BYTES ===========

Now determine how many Megabytes a quota of 262144 blocks equals:

1) 262144 multiplied by the size of the blocks:

262144 x 1024 = 268,435,456 (number of total bytes)

2) Since we are dealing with megabytes, divide by 1024 x 1024

( 268,435,456 / 1048576 ) = 256