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Posts Tagged ‘linux’

Linux Kernel MTRR Trim problems

13 Mar

I recently came across an interesting problem with a newly purchased set of servers. These were HP DL165 G7, very nice 1U machines with dual sockets and capable of good RAM expansion. Once the OS (64 Bit CentOS) was booted it couldn’t see the full 16GB of installed memory. The memory being reported was only 3011MB, 3GB approx.

On closer examination it was established that the dmesg log had a indicated a potential problem, the message suggested that some of the memory, although detected by the kernel was “trimmed” and the box was left with 3GB to run.

The problem was fixed by enabling the kernel argument “disable_mtrr_trim”.

 
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Posted in Kernel, Linux

 

My first C/C++ learning environment – Quincy

30 Oct

When I was about to start learning C programming back in college many years ago, I took a peek at what was about to come my way. I had some issues understanding the ‘cryptic’ syntax. I was familiar with Turbo BASIC from Borland Corp and could program quite well in it. I started looking around for some good book to learn C. I found a very nice book named ‘Al Stevens Teaches C’, it was an interactive tutorial that accompanied a C interpreter with it. This is the same Al Stevens who used to write great articles in Dr. Dobb’s journal. I enjoyed the way he took me through the core concepts and simplified approach to C syntax. The interpreter allowed very quick testing of the code I produced and it was pure fun.

You might be thinking why a post on such an old thing, well the interpreter created by Al was special, I loved it and I have recently been looking for it. I didn’t find the original text based version, but I was able to locate a newer GUI version that runs on windows or WINE on top of Linux. This specific version was produced in 2005 and works like a breeze. Its not an interpreter anymore. It is now more of an IDE built around the GNU C compiler. Its something nice for those who wish to No need for those bulky commercial compilers for newbies anymore, just get your hands on Quincy and get on with your learning with the power of open source.

By the way, I must mention that Quincy was named after the adorable cat of the author of the book, I wonder if the cat still lives? You’ll find a photo of her in the program logo.

You can download Quincy from this link.

http://www.uploadmb.com/dw.php?id=1255959978

More information can be found at http://quincy.codecutter.org

 
 

gOS – Lightweight Ubuntu for Netbooks

15 Sep

 

gOS Logo
gOS Logo

gOS or “good OS” is an operating system created by ‘Good OS LLC’, a Los Angeles-based corporation. The company initially advertised it as “An alternative OS with Google Apps and other Web 2.0 apps for the modern user.” The first version gOS was based on Ubuntu 7.10 and the Enlightenment window manager.

Based on the idea of cloud computing, all versions of gOS lean heavily on on-line applications built on Web 2.0 and AJAX technology so they also do not use much hard disk space for applications. The whole gOS-1 system fits comfortably in less than 2 GB of disk space. Also many of the documents created with gOS, such as Google Docs documents, can be saved on Google servers instead of on the local hard disk, so gOS can work with very small hard disks. In gOS V2 Rocket, Good OS introduced the use of Google’s “Google Gears” technology which promises to make Google’s web applications usable without an internet connection. Currently, Google Reader and Google Docs are the only supported Google applications. Read the rest of this entry »