At times, I’ll kick off an I/O intensive process, like running aide, or generating a photo album. I don’t want those things to interfere with the interactive feel of my Linux system. I stumbled on the following solution:
chrt --idle 0 ionice -t -c3 <program>
SELinux in Fedora 14 is configured to constrain the ports on which SSH can listen (see the bug report). The solution:
setsebool -P sshd_forward_ports 1
This allows SSH to listen on ports besides 22, and to forward ports. Reading the bug report is interesting. In my opinion, OpenSSH has an outstanding security track record, and we probably don’t need additional SELinux policy to constrain it. It’s probably wise to practice security in-depth (to have more than one line of defense), but it creates a large road bump for most SSH power users. From what I read, it sounds like most people still disable SELinux.
One of my QA coworkers had The Linux Phrasebook sitting on his desk. I noticed it was by Scott Granneman, and immediately thought, “if it’s by him, it’s got to be good.” As I thumbed through the pages of the book, I was impressed at the practical coverage of command line utilities including yum and rpm, apt and deb, etc. I highly recommend this book. It’s small so it’s easy to keep on hand.
For anyone wishing to write applications that take advantage of all that Linux has to offer, I recommend The Linux Programming Interface (also available from Amazon), aka TLPI. I used to recommend Stevens’ Advanced Programming in the UNIX Environment, but now I recommend TLPI because it is more comprehensive and just as readable. It’s not a small book, so a PDF makes it easier to keep on hand. I purchased my copy through the publisher, NoStarch with the coupon code “Mamaku” that gave me 30% off and a free PDF. The order total came to $80.00, including shipping.
When I needed to figure out where the performance bottlenecks were in some Linux software, I found helpful answers at http://stackoverflow.com in the form of two tools: 1. naming threads in combination with “top -Hp <pid>” and 2. “pstack <pid>”. The first was helpful in watching which threads were consuming the most CPU. The second was useful in sampling the application over time to find the hot spots and their stack traces.
Six months ago, I replaced the failing hard drive in my Linux laptop, and already, the SMART tools are telling me that I should back up and replace the hard drive — a high number of sectors have gone bad.
Hmmm. What’s this? SMART also reported that the hard drive had reached “overheating” temperature ranges. Why would that be? I did some Google searching, and came up with the following advice:
Based on a tip from my father (a long time Linux expert), I ran “smartctl -H /dev/sda”, and it says “SMART overall-health self-assessment test result: PASSED”. I assume it means the hard drive is still okay, but I had better not forget to make regular backups, and monitor the status of the hard drive.
Janice gave me an iPod Touch, 4th generation, for my birthday. Here’s my take on it, compared to a Palm T|X and a Nexus One.
I’m going to take a list of features that I claimed I wanted, and recast it in terms of the iPod Touch. Next, I’m going to describe what pleases me about the iPod Touch, followed by what is annoying.
Things I love about the iPod Touch:
Apps I love:
Annoyances:
I’ve never owned an Apple device until now. They’ve created an excellent device with the iPod Touch. It’s not perfect, but it’s adequate to replace my Palm TX as a personal digital assistant, and in many ways, it’s far superior.
“In 1976, the basic computational power of a $200 iPod would have cost one billion dollars, while the full set of capabilities would have been impossible at any price, much less in a shirt pocket.” — Erik Brynjolfsson, Paul Hofmann, and John Jordan, Communications of the ACM, May 2010, p 33.
In early October, I attended the Utah Open Source Conference. I’m not sure what outsourcing has to do with Open Source, but it was one of the more interesting presentations I attended.
Outsourcing, by Scott Lemon of HumanXtensions L.L.C.
Scott worked for Novell, and they had a development center in India, which is what got him into outsourcing. That was back in 2000. Since then, he’s refined his personal model of outsourcing.
Q: You suck! Are you taking our jobs offshore?
A: No. You are in control of your own destiny. You are in control of the value you create in an organization. People in other countries want the American dream that we’ve “pimped” to them. Those people are educated, hard working, etc.
Leveraging…
Communications…
Email isn’t any good. You have to use good project and task management tools. There are delays in email. You can’t track tasks via email.
Acunote is good for larger scale projects than Basecamp, but they do use Basecamp for smaller projects. Their projects are anywhere between $20K to $150K.
Where to outsource…
An audience member said: One thing to remember is that some countries devalue their currency. So, if you an overseas employee $1 per hour, that dollar has more buying power than we realize, in their own country, compared to our own.
Scott met with attorneys in the Philippines to write up legal contracts, and because he wants not to be arrested — he wants to abide by the law. He hires his people as contractors, because it’s so difficult to fire employees.
He found a real deal with Wells Fargo that makes it free for him to transfer payroll to a bank in the Philippines — because he already has a bank account and a mortgage through Wells Fargo. He uses WF for payroll as well.
He’s not saying that you have to outsource to the Philippines. Pick a place that works for you.
Who does he hire?
He picks recent graduates. He didn’t want the rent-a-coder model, but someone that works for him, and is committed to him or his company. He hires people outside of major cities! It’s far cheaper that way, and easier to find people. He has a lot less risk of losing that employee. Recent graduates are trainable.
He recently hired 5 guys. He told the candidates what tech he was hiring for. The candidates went out and learned the tech, and wrote demo programs in the technology that they could show up at the interview.
With recent graduate new hires, he can lay out a wage growth plan over ten years.
How did he do it?
He didn’t sit on Google trying to figure it out. He flew to the Philippines. He listed jobs in local job boards two weeks in advance. While there, he met with university professors, scheduled interviews and made offers.
Standardized tools…
Patterns of operation…
A day in his life…
He takes breaks on weekends. He does do things Sunday night, because that’s Monday morning in the Philippines.
His business doesn’t do the graphic design of websites — just the system and the infrastructure.
Scott seemed to think that Objective-C is a dead-end one-trick pony. He leverages Titanium to let his guys do JavaScript to develop iPhone and Android apps.
They do the testing of the apps. Customers pay for new features and maintenance. Customers get to hammer on a test server as well before deployment.
His contractors have to do their own taxes. He reminds them of this.
Q: What about the Philippine employees ripping off his intellectual property?
A: He worries about it just as much as he would with American employees. This is what contracts are for, and the legal system.
He uses Balsamic to prototype things. His offshore devs build his prototype into a product, and make it far better than his mockup. His devs are very capable and skilled.
I use ‘rdesktop’ from my Linux box to connect to a Windows machine. rdesktop can forward sound using the “-r sound” option, but it stopped working in Fedora 11, when PulseAudio made its appearance.
The reason is because:
The workaround, for now, is to, run this, as root:
sudo modprobe snd-pcm-oss
In August, reports of Windows DLL hijacking flaws surfaced. Lest Linux users get too comfortable thinking that they’re more secure, a similar problem can happen with dangerous use of LD\_LIBRARY\_PATH.
It’s a pain to recover from a failing hard drive, even months after the fact. The hard drive in my Linux server (a laptop), started going bad in May or June. Since it was still under warranty, HP replaced it.
Before I sent the drive back to HP, I copied what I could recover from it, and I restored the other files from backup. Or at least, so I thought. Tonight, I discovered that my music collection is missing. The file folders are there, but the mp3 and vorbis files aren’t. Not a big deal, since I have the CDs, except for the few albums that I purchased as mp3s. “What else is missing?”, I wondered.
find $HOME/Photos -depth -type d -empty
It turns out that some of my photos are missing as well. It’s a good thing I didn’t delete my backups once I thought I’d completely restored from them.