magicJack's "No Audio Found" Error Message

I had an issue with my magicJack phone. I could hear it ring and it had a dialtone but I could not dial out or receive calls. As a useful working indicator, I should see magicJack's stock symbol (CALL) on their desktop GUI. Instead, I observed the "No Audio Found" message.  Predictably, I rebooted my PC a couple times but no change. I decided to visit the PC's Device Manager.

I invoked the "Control Panel"=>"Hardware and Sound"=>"Device Manager"=>"Sound, video and game controllers" and then uninstalled the USB Internet Phone by TigerJet driver. Then I physically removed the magicJack device from the computer's USB port and then reattached it about 20-30 seconds later. Its driver was automatically found and re-installed. Now I could see magicJack's Stock Symbol: CALL on their GUI. At any rate, it works.

I never had a issue before but I think I had a conflict with another recently installed USB device.

Of course, you might get this error and it's something else. This is what worked for me.

By the way, the OS name is Windows 7.

How to Exclude a Directory for TAR

I am doing a few aesthetic upgrades, so naturally I want to backup some of my website files. However, I do not want everything, i.e. transient files such images. I tarred up the website's primary directory but excluded its images sub-directory.

Frankly speaking, I did not want to waste time and bandwidth downloading images. Here is the syntax to exclude a directory.

# tar cvfp mytarball.tar /mypath/Example.com_DIR --exclude=/mypath/Example.com_DIR/images

Tar everything in the current directory but exclude two files

# tar cvpf mytar.tar * --exclude=index.html --exclude=myimage.png

Restore MySQL Database via Command Line

This is mostly a note to myself. It is not really a tip.

Restoring a mysql database from the command line.

[root@server]# ls -la

total 326940

drwx------ 3 user1 usergrp 4096 Oct 29 12:10 .

drwxr-xr-x 3 root root 4096 Nov 4 05:22 ..

-rw-r--r-- 1 user1 usergrp 1239136 Oct 29 12:10 mysql_db.sql

[root@server]# pwd

/backups/db/backup

[root@server]# mysql --user=mysql_user --password=somepasswd mysql_backup < mysql_db.sql

Sun StorageTek 6140 Cache

We have a Sun StorageTek 6140 Array attached to a couple NAS heads. We share out its file systems from the NAS. But it seemed the NAS was creating bottlenecks and hanging NFS. As usual, it turned out to be something else.

We observed slowness during high or bursty I/O operations. Short story...It was the 6140's cache. Make sure your cache batteries are good to go and up to date. They have a 3 year shelf life. It will save you a lot of frustration in the long-run.

HTML Symbol Entities issue on Blogger

I have received a few requests on how to deal with the HTML Symbol Entities issue on Blogger. There really isn't a problem because you can just click the box below for your post and your character(s) will display correctly.

ERROR

Your HTML cannot be accepted: Tag is broken: xxxxx

Stop showing HTML errors for the body of this post

However, here are some good references for HTML Symbol Entities

http://www.w3schools.com/tags/ref_symbols.asp

http://www.ascii.cl/htmlcodes.htm

http://www.webstandards.org/learn/reference/charts/entities/symbol_entities/

http://webdesignerwall.com/tutorials/using-html-symbol-entities

http://www.entitycode.com/

Log an FTP Session with a Filter

A couple colleagues and I were looking for an effective way to tersely log the activities of an FTP effort. All we wanted was the file name and throughput rate. If you are Ftping hundreds or thousands of files, the first one (below) could be quite verbose, especially if you have a security banner notice. Here are a couple ideas that we considered. We went with the alternative (a lot less text-based overhead).

#!/bin/sh

ftp -nv some_host ›› /tmp/myftplog ‹‹EOFTP

user some_user some_password

cd /some_dir/some_dir1/some_dir2

binary

put some_image.jpg

EOFTP

and its log...

$ more /tmp/myftplog

Connected to some_host.

220 ProFTPD x.x.x Server ready.

331 Password required for some_user

230 User some_user logged in

250 CWD command successful

200 Type set to I

200 PORT command successful

150 Opening BINARY mode data connection for some_image.jpg

226 Transfer complete

ftp: 26753 bytes sent in 0.00Seconds 26753000.00Kbytes/sec.

221 Goodbye.

###ALTERNATIVE###

#!/bin/sh

ftp -n some_host ›› /tmp/myftplog ‹‹EOFTP

user some_user some_password

cd /some_dir/some_dir1/some_dir2

binary

verbose

put some_image.jpg

EOFTP

and its log...

$ more /tmp/myftplog

Verbose mode On .

200 PORT command successful

150 Opening BINARY mode data connection for some_image.jpg

226 Transfer complete

ftp: 26753 bytes sent in 0.00Seconds 26753000.00Kbytes/sec.

221 Goodbye.

Display it...

$ tail -f /tmp/myftplog

The Importance of Library Level Integration in Open Source Environment

By Jonathan Flack

Open Systems Engineer, Likewise Software

As an Open Systems Engineer at Likewise Software I routinely encounter unique customer problems. Most of these problems require a clever solution which tends to be specific to the customer site.

Earlier today, however, I got a query from an Ubuntu user that really made me consider how important library level integration by application developers can be when administering an open source environment. A lot of vendors out there provide free solutions without being open source, and a lot of these solutions solve one problem or another in your environment, but it's rare to come across a piece of software that really cleanly integrates into your deployed OS in a way that provides a multitude of very clean solutions to everyday problems.

This user had a simple Linux application for which he needed to verify user authentication by simply passing the username and password to generate a pass/fail response. The application was neither pam/nsswitch integrated or GSS-enabled (built with GSSAPI support).

The user's Linux environment was already authenticating to Active Directory using Likewise Open, our open source agent which allows user authentication against Microsoft's Active Directory. As a result, I know the user would have access to a fully functional Kerberos KDC.

Anyone who has integrated Kerberos in a large environment before knows configuration can be a very painful experience. Likewise Open however, properly configures the client side kerberos and server side DNS automatically during domainjoin, so this little trip down nightmare alley is completely avoided. We are also assured that the configuration is correct.

So the only thing left to do is leverage kinit to authenticate the user against AD's KDC.

The specifics of the code in his application are not relevant, but you can see a simple example of this working using kinit from the command line:

Positive Authentication -

[root ~]# kinit joesmith@MYDOMAIN.COM

Password for joesmith@MYDOMAIN.COM: ************ <== Correct Password

[root ~]# echo $?

0

Negative Authentication -

[root ~]# kinit joesmith@MYDOMAIN.COM

Password for joesmith@MYDOMAIN.COM: *^^^***^*** <== Incorrect Password

[root ~]# echo $?

1

This shows how tools which properly integrate across multiple subsystems ease the workload on already overtasked admins. It also clarifies the importance of open-standards based integration. By integrating directly with pam, nsswitch and Kerberos, Likewise-Open allowed him to leverage existing machine configurations and his AD authentication to easily solve a problem unique to his custom application.

One of the great side benefits is knowing that any other kerberized application, like Firefox or OpenSSH, will authenticate using the user's AD credentials as well.

This kind of elegant solution has been rare in large heterogeneous environments, but more and more open source developers are striving to achieve a high level of standards based integration without forcing closed source components on their end users. This is one of the clear long-lasting benefits of the open source movement and I'm very pleased to see more companies making this as part of their products' value proposition.

The Khan Academy is Teaching the Online World

Here is a great learning site to help brush up on your algebra, geometry, trigonometry, and calculus skills. You can also find courses for economics, finance, history and science. This growing site is called the Khan Academy. The instructor, Salman Khan, is helping current students and former students gain or regain their footing with these topics. He basically provides a 10 minute block of instruction (due to youtube’s time limit) on a given topic, which is short enough to keep your attention span. His site offers over 1800 different courses.

Salman gave up a successful career in finance to share his vast knowledge with the world for FREE. From what I can see, he’s a terrific math teacher.

The Khan Academy is a not-for-profit 501(c)(3) with the mission of providing a world-class education to anyone, anywhere.

Check out the Khan Academy and its amazing story.

And by the way, the Academy was recently selected by Google's project 10^100

Use Redirect Symbol to Zero File

I have mentioned this topic in an earlier post - zero'ing logfiles with cat /dev/null > logfile. But there is another easy way to zero a logfile in Bourne or Korn shell. It probably works in Bash and Zsh, too. I have to check. Here is an example below.

Note: I used the gts to represent the "greater than" or redirect symbol because blogger complained about using that particular character. Update: themadengineer reminded me on the use of "greater than" html syntax. Thanks.

Bourne Shell at the command prompt

# > mylogfile

or

Korn Shell at the command prompt

# > mylogfile

Earlier post: Don't remove those log files - zero them

Run the Windows Explorer GUI

Here are a few easy ways to invoke the Windows Explorer GUI, which displays certain parts of the directory/folder tree depending on given syntax. I also threw in a few other miscellaneous items.


1. Select Run
Then type "."
This action will invoke the C:\Documents and Settings\mysysad


2. Select Run
Then type ".."
This action will invoke a window that displays C:\Documents and Settings


3. Select Run
Then type "..."
This action will invoke a window that displays My Computer


Other misc Run exercises


Select Run
Type "explorer" - same as Type "My Documents"
Type "explorer c:"
Type "explorer desktop"
Type "explorer ."
Type "explorer .."


Select Run
Type "control panel"

Select Run
Type "recent"


Select Run
Type "calc"


Select Run
Type "notepad"


Select Run
Type "wordpad"


Select Run
Type "ping MySysAdDOTCOM"


Select Run
Type "c:" or "d:" or "a:"


Select Run
Type "freecell"
Type "sol"
Type "mshearts"
Type "spider"
Type "winmine"


Select Run
Type "mspaint"


Select Run
Type "nslookup"


Select Run
Type "cmd"