Linux Blog

Fedora 11 Beta Release

Filed under: General Linux — TheLinuxBlog.com at 11:14 am on Tuesday, March 31, 2009

The Fedora Project Announced today that they were releasing the Beta version of Fedora 11. Stupidly I went and downloaded it. After installing from the live CD which I had never done before (It went really smoothly) I had realized I’d installed the Alpha release. Nice!

So now I’m trying to figure out how to update from the Alpha to the Beta and reading over the Fedora 11 Beta Release Notes. A lot has changed and I really wanted to give ext4 a shot but I guess I’ll just wait till the stable comes out.

Homemade Bench top Power Supply

Filed under: Linux Hardware,The Linux Blog News — TheLinuxBlog.com at 1:06 am on Tuesday, March 31, 2009

Homemade Bench Top Power Supply

I’ve always had an interest for electronics and recently I’ve been exploring my interests more. Last week I sorted through my tub of parts and placed them in individual draws. It took a good while to sort everything but I think it was worth it. I’ve seen power supplies built from PC power supplies before so I thought I’d build one my self. Thing is, I never really got around to it.

Yesterday I was feeling rather ambitious and decided to make a bench top power supply for small electronics. All the sites I found I have lost, so I kind of made it up as I went along. Most of them used ATX power supplies that are readily available, but I opted for the easy way out and used an AT with a hard on/off switch. At first this was the only reason I used it, but there are more advantages to using a AT over an ATX power supply for an external power supply. Firstly, it was cheap, well free actually. I took it from a PC that I had modified some time ago. I have a box full of AT power supplies in storage that I’ll get to some time and replace it. But I won’t be using the PC it came out of for a while, mostly because I have toaster ovens that are faster. Another reason it is better than a ATX is it has less voltages. The only voltages listed are 12v, 5v, -5v (7v) and GND. They vary in amps but are sufficient for what I will be using it for. It made it easy not to screw it up since there wasn’t many wires.

To make it was really easy. I took the top off. Drilled 4 holes in the case and inserted the insulated terminal, checking to make sure they didn’t ground out on the case. Cut most of the cables, leaving a couple of molex’s hanging out just in case I need them. I then soldered the remaining wires to a terminal by voltage (Yellow +12, Red +5, Red +/-5, Black GND.) It might not be the prettiest of them all, but I think it will do its job well.

APC Access Temperature Query and Conversion. (2 of 2)

Filed under: Shell Script Sundays — TheLinuxBlog.com at 6:55 pm on Sunday, March 29, 2009

This second part of the script APC Access Temperature Query Script and its been a long time coming. Basically this script is the part that runs as a cron and will e-mail me if the temperature goes over a certain threshold. Once it returns to normal it e-mails me again. It has the option to send a text message to me via my SMS gateway, but it is commented out.

#!/bin/bash
 
temp=$(/home/linux/bin/temp f)
threshold=76
 
if [ "`echo \"$temp > $threshold\" | bc`" == 1 ]; then
echo $(date +%s) $temp >> /home/linux/thermal-over.log
echo "High Temp";
 
if [ "$(cat temp.txt)" == "norm" ]; then
echo "Sending E-Mail, High Temp";
echo "Current Temperature Is: $(/home/linux/bin/temp f)" | mail -s "Thermal Overload" owen@linuxblog                #echo "Current Temp Is: $(/home/linux/bin/temp f)" | mail -s "Thermal Overload" mynumber@cingularme.com
echo "high" > temp.txt
fi
elif [ "`echo \"$temp < $threshold\" | bc`" == 1 ]; then
echo "Low Temp";
 
if [ "$(cat temp.txt)" == "high" ]; then
echo "Temp Resumed, Sending E-Mail";
echo $(date +%s) Resumed at: $temp | mail -s "Thermal Normal" owen@linuxblog
echo "norm" > temp.txt
fi
 
fi
 
echo $(date +%s) $temp >> /home/linux/thermal.log

When I first wrote the script, I did not do any temperature checking. I found out that I needed to when I came back one morning with a bunch of emails that I needed to delete. Its pretty simple to figure out, temp.txt holds a value that is either norm or high. It gets switched when the temperature changes, this will in turn stop it from e-mailing me repeatedly. Once the temperature drops it flips it back. It will still e-mail if your temperature fluctuates between 75 and 77 which can be annoying, but you can adjust the threshold with the variable and set it to what you need. Thankfully our chiller has been fixed and I no longer have to worry about the temperature, but it still runs on a cron just in case.

Academic Earth – Go Learn something.

Filed under: The Linux Blog News — TheLinuxBlog.com at 1:12 pm on Thursday, March 26, 2009

Some one (and I’m sorry if I’m breaking some sort of twitter code here) but I can’t remember who tweeted about this website called academic earth (http://www.academicearth.org/) The concept is simple, go there and you can watch video’s or lectures from some famous professors. I watched one on physics, but could not finish it. My thoughts through out this entire video were something as follows:

“This is a college course?”
“This is a college course at MIT?”
“This guy is nuts”
and
“Why are they using overhead projectors.”

So my time at MIT didn’t go very well, but atleast I didn’t pay for it. Anyway maybe you’ll do better. Head over to academicearth.org and watch some videos. Let me know if you find anything particurly interesting relating to technology – The introduction to robotics was cool, although I don’t think we should be teaching our students how to make killer robots.

DFD Today

Filed under: The Linux Blog News — TheLinuxBlog.com at 12:48 pm on Wednesday, March 25, 2009

No, not Dataflow Diagram. Document freedom day. Undoubtedly you’re are aware that it is today, given the amount of press it has got and what a good cause. I was thinking about how I could participate in Document Freedom Day. A few things came to mind. The first was was:

“How about I save all my documents in .odt, that will teach them.”

No go on that one, I already do that because I’m too lazy to save into .doc. I also call the “open source” people out on it when they ask me to save as .doc because it “works on Windows”.

“I could translate all the .doc’s and .docx’s on the file server to an open format.”

Well, my wife just lost her job, I don’t need to lose mine too, although it would be hilarious and it would raise awareness.

Too bad, I’ll have to do nothing this year, perhaps next year I can join the celebration if there is a “Team” in my area. They should really make it a Friday. I’d totally go out and down a few beers in the name of document freedom.

Aim for the Simple, not the Turd.

Filed under: General Linux — TheLinuxBlog.com at 10:18 am on Wednesday, March 18, 2009

TurdWhen something doesn’t work as expected, or stops working, for your own sake try the simple things first. It may seem pretty obvious to most people, but sometimes we all need a reminder. Recently I have been over complicating problems and landing in giant piles of turd.

I was going nuts one day because I couldn’t listen to streaming radio while I was trying to work. I started messing with all the settings, reconfiguring my sound card. I Removed the sound module and probed it again. Turns out that the reason my headphones were not working was because the cable was unplugged. Hey! it happens with those Dell’s with the slanted front inputs, but I’m still stupid for not checking the speaker volume first.

Fortunately this one was not me, but is still a funny story and something I’m sure most technicians will be familiar with.
User: “I can’t connect to the network”
Tech: “Is it plugged in?”
User: “How do I plug it in if it’s wireless?”
Tech: “Oh, why didn’t you say? Are you sure you’re connected to the right network?”
User: “How do I tell? The thing that normally tells me is gone”
Tech: “Ok, I’ll be there in a sec”
The technician tried to reinstall the driver, change the firewall settings and everything possible. Turns out they forgot to ask them if they’d hit the wireless function key.

Fresh off of the stupid, this one just happened to me five minutes ago. I was switching my KVM over to my Windows machine. I got nothing but a black screen and monitor telling me it was going to bed. My mind told me that Windows had crashed as usual and that I better shut it down and restart. I pressed the power button and waited. I’m used to Linux shutting down pretty quickly so since it was taking its time, I thought it had properly frozen up like it sometimes does. I held the power button in for the dreaded five seconds, poured myself a cup of coffee and turned it back on. What? Nothing! oh yea, I was rummaging around down there yesterday. What’s this? A loose video cable? Crap!

Who’s the sucker now?

Next time you jump off of the diving board of problem solving just remember to try the simple solutions first.
I’d love to hear your stories, and the pile of turd you landed in.

uCertify Linux+ CXK0-002 Exam Preparation Material

Filed under: General Linux,Linux Software — TheLinuxBlog.com at 12:03 am on Monday, March 16, 2009

How many people have ever considered getting certified in the Linux field? I’m sure there are a lot since there are a number of certifications available, RHCE, LPI, Novel/Suse and CompTIA’s Linux+ to name a few. Now, think of the number of study materials and exam preparation available for each of those. The number can almost be overwhelming.

uCertify have study materials available for a number of certification vendors. The vendors that are of specific Linux interest are CompTIA and LPI. Today I’ll be giving you my perspective on the Linux+ study material. I have already sat and passed the Linux+ XK0-002 exam and with the new one coming out pretty soon (Feb 17th was the Beta release date) I would recommend you take it too.

The first thing I did after downloading the uCertify preparation material was try and install it on Linux using wine. It failed on installation, but it may be able to work with some configuration tweaking and file copying. No time for that though, if your studying for an exam you need to get on it and start. So install it in a virtual machine or on a Windows box to save time.
uCertify’s interface is very easy to navigate and is organized well, it also has a clean interface which is easy on the eyes – great for those late night study sessions. The CXK0-002 exam has ample practice tests and study material. There are a number of methods of studying for the exam including:
Flash Cards, Study Notes, Articles.

There is not a large amount of text explaining theories and concepts in great detail but the study notes and flash cards are great at refreshing your memory and helping you remember what’s on the exam. The practice tests and assessments are pretty good but can be tricky – just like the real exams. Remember they are not only designed to make you pass, they guarantee it!

Probably the biggest question I have when studying for a certification is
“Am I ready to take the Exam?”
Most times, I opt for “no” and do more studying. The uCertify preparation engine takes the guess work out by giving you “tracking” features. Basically these features allow you to track your past test scores and take the practice test. It will let you know when you’re ready.

Conclusion
All-in-all I think the uCertify preparation engine with the CXK0-002 material loaded is a good method of studying for the Linux+ exam, especially if you are familiar with the concepts and terminologies outlined in the exam objectives. If you are new to Linux and are looking for the best all inclusive study material out there, I don’t think that you would want to use this alone. I’d recommend reading a book or using video training aimed at bringing you up to speed in addition to a good preparation material. uCertify’s preparation can definitely fit the latter’s shoe’s.

Run Levels in a Nutshell

Filed under: Quick Linux Tutorials — TheLinuxBlog.com at 9:03 am on Wednesday, March 11, 2009

Run levels in Linux are a great thing. Basically, a run level is by definition a configuration for a group of processes. The run levels and default run level is specified in /etc/inittab. Most Linux systems these days, with exception of a few boot into run level 5 which is generally a graphical user interface such as KDM or GDM. The others boot into run level 3 most servers will boot into this run level which is multi-user with networking but no X, and is many users preference.

To define what run level your system boots into by default you would edit the /etc/inittab file and edit the line similar to:

 id:5:initdefault:

This is run level 5, if you wanted to switch to command line you’d change the 5 to 3 and vice versa.

If your not ready to make the jump yet but would like to check it out, you can (as root) use the command telinit to tell init to change run level. If you are in run level 5, try (be prepared to lose everything in X, as it will kill everything for you)

 telinit 3

If you are doing maintenance, you may want to switch to level 1 which is single user mode. Level 2 on Fedora is the same as 3 except it doesn’t have NFS support.

Level 0 is halt and run level 6 is reboot which are the best ones to accidentally set as a default run level (trust me on this one.) For more information on the different run levels check out the man pages.

Whats old is New!

Filed under: General Linux,Linux Hardware — TheLinuxBlog.com at 1:41 am on Tuesday, March 10, 2009

There was a display in a local library showcasing “What’s old is new again” Basically showing the similarities between new and older newspapers and the cartoons in them. It may have something to do with the NY Times tour, but maybe not. All I know is it was there the other day, and now I go to write about it – GONE. Many of the same concepts such as recession “funnies” are popping up again. What so these journalists and cartoonist’s have it easy eh? All they have to do to get their job done is find some old drawing and change it a little. Well, I’m jumping on the bandwagon folks. Here are two “What’s old is New!” Articles:
Living without Windows
Shell Scripting 101
Since they’ve been written we’ve learned a lot, new concepts are out there but while they are somewhat older, the concepts still apply. As everything old they enjoy receiving comments but don’t take criticism well. They know their faults such as bad spelling and grammar but their ageing and refuse to acknowledge their flaws unless you directly point them out. Give them a read and talk to them before they die and go to internet Heaven (or Hell).

Want a Free Linux Journal Subscription?

Filed under: The Linux Blog News — TheLinuxBlog.com at 2:26 pm on Monday, March 9, 2009

Psst. Want a Free Linux Magazine Subscription? Not just any magazine, the original Linux magazine The Linux Journal. If you missed out on the fifteen issues for $15 then this may be a better deal for you. This is not one of those scams where you get a free magazine in exchange for a limb at the end of the year. Basically each day there is going to be a Sesame Street “Today’s episode brought to you by the letter…”. At the end of the week, you have to unscramble the letters and submit your answer. Every correct answer submitted *cue count voice* “One HA HA HA HA” second before Sat 14th March gets a free digital subscription to The Linux Journal! It couldn’t be easier. Although, I still think you missed out on the $15 for fifteen print issues. Oh well, follow me on twitter @LinuxBlog and next time you’ll know.

Adjust sudo timeout

Filed under: Quick Linux Tutorials — TheLinuxBlog.com at 1:05 pm on Thursday, March 5, 2009

SudoI think its pretty evident that I love sudo right? Well, what I do not like about sudo is the timeout. I understand while its there but five minutes is not exactly what I’d call an overly generous time, especially when I’m parked here at my desk for hours upon end. This tutorial shows you the line you’ll need adjust the sudo timeout:

First as root you’ll want to get into the sudo file and edit it. I’m sure you know how to do this since you’ve probably already visudo’ed your way into using sudo and are now trying to adjust the timeout. For those just reading for the sake of it, you’ll do the command: visudo

Right, now you’re there, you’ll either be in nano, pico or vi depending on your distribution. Search for the Defaults section, and put

Defaults:[your username] timestamp_timeout=[your timeout]

Replace your username with yours. Change your timeout to the number of minutes, or -1 for unlimited per session. Save and quit, then exit. Try it again, then try it again after the sudo timeout you set has changed. If it works, great news if not double check your sudoers file for another Default property that may be acting up.