Letters

Readers sound off.

Ultimate Linux Box Cooling?

I was impressed by the desire to make a quiet PC—more people should complain to their OEMs/System integrators about this—it is the only way it will be fixed [“Ultimate Linux Box”, August 2005]. But I am not sure that removing 100% of the airflow is a positive thing for overall system performance or stability.

I have seen motherboards designed where the processor power supply components can exceed the design rating from the suppliers without airflow. Even if things don't go bad enough to cause system stability issues, it can damage the processor by allowing the CPU voltage to go out of specification. Intel is so concerned about this—they are telling motherboard manufactures to add circuits to the motherboard to monitor the temperature of the processor power supply and modulate the clock of the processor if things get too hot. See Section 9.4 in download.intel.com/design/Pentium4/guides/30235604.pdf.

Thanks—and looking forward to more sub-minute kernel compiles.


Robin

Whenever you experiment with any alternate cooling method, always measure and log temperatures. —Ed.

Linux/BSD Confusion

My child is almost two in the picture. The laptop is running KDE on FreeBSD. He quite plainly CALLED it “Linux”. My wife and I both looked at each other and at him and he said it again. He has also said “Ethernet”. We are afraid, very afraid. Thanks for a (decade of a) great publication!


kurtseel

More on the ULB

I'm used to reading the annual Ultimate PC article in Maximum PC magazine each year, and they give a great deal of detail and many more pictures than the Ultimate Linux Box article [August 2005]. However, the big difference between the two articles is that your Ultimate Linux Box does much more customization.

The big question is, if I want to replicate the Ultimate Linux Box, where would I get details on the custom-made power supply cooler modifications?

I went to the Resources page, but many of the things I would need to access require that I'm a Linux Journal subscriber. I have subscribed to the Linux Journal in the past, but for the last year, I simply run out and purchase Linux Journal.


Dean

Articles from that issue will be openly available soon. We'll look for more info on the power supply mods. —Ed.

Ten Years of Progress

The shock has worn off from seeing my name in Linux Journal, and I'm able to write again. [See “Ten Years Ago in Linux Journal”, July 2005, page 14.] Has it been ten years since “Novice to Novice” appeared in Linux Journal? It must be. I stopped writing the column after my first child was born and—bless it! —if it's not his tenth birthday already.

And how much has Linux changed (and stayed the same) in ten years. Though I haven't quite made the switch away from Microsoft, I did recently install Fedora Core. In ten years, installation has vastly improved since when I used version 0.99 of Slackware. The Fedora installation was relatively fast and idiot-proof. Everything worked except the modem, and although I'm finally getting DSL installed, I wanted modem access as backup. Turns out I have a PCTel modem, which seems unsupported by the 2.6+ kernel and by the drivers currently out there in Webland.

(Hmmm, could be another “Novice to Novice” here.)

But what's blown me away about Linux are the live CDs. Knoppix and the variations are fantastic not only for emergencies but also just to learn *nix, which is why I got involved with Linux originally.

Ah well! Thanks for remembering me after all these years. Yes, I still have the 0.99 Slackware CD with the grinning Bob. It just seems right to keep it.


Dean

Become Boring and Pigeonholed, Please

Hi. I've been a subscriber to LJ for several years, and I've never figured out your niche. Servers, or desktops? Sysadmins, application programmers, system developers or home users? Your intention seems to be: appeal to everyone. Unfortunately for me, you cover so many different topics that there is very little in each issue for me.

If you can't figure out your niche, I'll let my subscription expire in January.


jh

When different areas of information technology can stop learning from each other, we'll pick a “niche”. —Ed.

Ergonomic Comments on Ultimate Linux Box

The case on the cover for your Ultimate Linux Box is gorgeous [August 2005]. Beautiful. Amazing.

It also blows. It's a terrible design. Ghastly. Ideal for a computer show, but awful to use. There's no legroom on the box. For many folks, that would mean sitting obliquely or too far from the keyboard—both would cause strain.

Tactile response acts as a brake reducing the amount of impact on the end of the fingers (while, agreed, increasing the finger travel) so the keyboard used may actually increase hand-stress for some. Its placement isn't adjustable for height, and that can be catastrophic for arm stress.

On a much less important note, I'd point out that the case puts the cooling up very high indeed, into airspace often several degrees hotter than the rest of the room.


Paul Pomerleau

The coolant loops need to run well above the motherboard in order to get adequate convective cooling. For daily use, you can build a tall case without the monitor mounts or keyboard shelf. —Ed.

Another Happy Reader

Here's a photo of my son Merit (about 26-months old) sitting on his trusty fire truck checking out my July 2005 issue of LJ. When he was done, he went back into the office and picked up an Advanced C Programming book!


tim

Pipe Tip

“Text Manipulation with sed” by Larry Richardson had some useful hints [July 2005]. For instance, I wasn't aware of the ! modification to the range field.

But writing to a file at the same time you are reading it is decidedly dangerous. You are depending on the pipe buffer between cat and sed to hold the entire contents of the file. You are also banking on the assumption that cat will be started and allowed to fill its buffer before the file is written and, therefore, truncated at zero length. A far better way to do this is in two steps:


sed -e 's/$/ mycomputer/' < /etc/exports > tempfile \
&& mv tempfile /etc/exports

The mv command is executed only if sed returns without problems. You don't want to be overwriting important files with the wrong data!


Allen Brown

Her First Computer T-Shirt

My daughter (2.2-years old) made the transition. She was introduced to Potato Guy and Tux Paint on my Linux box. On this day, she learned everything she needed to know about the mouse operations. A very proud moment for me, she is on road to becoming a geek just like her daddy. Elizabeth Su WOHID Certified (Wireless Optical Human Interface Device), T-shirt awarded shortly after. You can't start them too young. This is only the beginning for them. I am just happy to be there.


Jesse Apple

sed Tip

I read with great interest the article by Larry Richardson entitled “Text Manipulation with sed” [July 2005]. We're in the early stages of porting a MS Access application to Linux using MySQL and Qt to build the GUI. I've recently been working with sed, so the article hit the spot, so to speak.

One thing I noted missing from the article is the fact that when writing commands that substitute one string with another, for example, using slashes to separate the from string and the to string is only one option. Actually, any unique character could be used as a separator. In the example on page 81 (first column, second example), which reads:


cat customer.txt \
sed -e 's/Sam Jones/Samuel Jones/' > customer.txt

The slashes could be replaced by the plus (+) sign (or most any other unique character) as in:


cat customer.txt \
sed -e 's+Sam Jones+Samuel Jones+' > customer.txt

I've found this useful when I'm editing a file containing paths, such as /etc/exports. In this case, the command:


cat /etc/exports |
sed -e 's/\/windows/\/winNT/' >/etc/exports

reduces to:


cat /etc/exports |
sed -e 's+/windows+/winNT+' >/etc/exports




Bill Lugg

Patent Searching

I've liked open software since the time it had no name yet, when you were nearly a hacker because you had a 1,200-baud modem and a dial-up connection to some friend's BBS.

I'm writing from the old continent, where a battle is being played between software companies who want the ratification by the EU of the right for software patents and developers who don't want to have their mind and ideas limited.

And now the question: I suppose that any person should be granted the same rights as anyone else, but in the fight between open software and non-open software there is a disparity. Any company developing non-open software can check any open software to look for similar, copyright infringing, code. The same right is not granted to the counterpart. How can we be sure that Microsoft, Oracle, SAP or anyone else, is not importing code and concepts from open-source software? Maybe this issue has been discussed many times, but I couldn't find a definitive answer to it.


Andrea Rui

GPL violators do sometimes get caught. See gpl-violations.org for examples. —Ed.

Photo of the Month: A Linux Father's Day

I had a great father's day and hope all the other open-source dads did too. Of course, the best gift was Paige, my going-to-be-seven-in-September daughter—and you will see she painted Tux on a rock for me this father's day. She always has been a good drawer, and her favorite program is Tux Paint with Tux Racer a close second.


James M. Susanka

Photo of the month gets you a one-year subscription or extension. Send photos to ljeditor@linuxjournal.com.

LDAP Question

I just found your OpenLDAP article on www.linuxjournal.com [July 2005]. I notice you include the nis.schema, but you don't use NIS at all, correct? Thanks for any clarification.


Jiann-Ming Su

Craig Swanson replies: thank you for your interest in “OpenLDAP Everywhere Revisited”. You are correct that we are not using Network Information System (NIS). The nis.schema provides several essential attribute types that are used in our LDAP directory. For example, nis.schema defines the LDAP entries that take the place of fields in /etc/passwd. For background information on the history of NIS and LDAP, see the IETF RFC2307, “An Approach for Using LDAP as a Network Information Service”.

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