Debugging Embedded Linux with GDBserver and Insight (gdb GUI)

Although it it sometimes possible to debug applications using GDB (The GNU Debugger) on the target boards, there is often not enough memory available to run GDB on embedded systems running Linux. To work around this issue, you can use gdbserver to perform remote debugging. Installing and running gdbserver on the target board First of all you need to install gdbserver on the target board. Assuming you use a Debian based distribution:

If you distribution, does not have binary repository, you can download gdb source code and cross-compile gdbserver. Once gdbserver is installed, (cross-)compile your application in debug mode and start gdbserver as follows:

Where target_ip and target_port are respectively the IP address of the board and the chosen TCP port, and prog_dbg, the program under test compile in debug mode (CFLAGS=-g). Remote Debugging with GDB If you are familiar with gdb and prefer to use the command […]

How to Find IP Address Ranges Owned by a Company

If you have a firewall, you may want to whitelist and/or blacklist some IPs depending in the origin. Usually it’s easy to find the owner of an IP address, but how can you find the IP address(es) registered by one specific company ? Let’s say you want to whitelist Technorati bot. A simple way is to go to http://bgp.he.net/ and enter the company name (e.g. technorati). It will return the IP list as follows: Result Description AS16936 Technorati, Inc. 208.66.66.0/23 Technorati, Inc. 208.66.65.0/24 Technorati, Inc. 208.66.64.0/24 Technorati, Inc. 208.66.64.0/22 Technorati, Inc. I understand the AS entries correspond to the Internet provider, and the IP address ranges can be added to your firewall (I use CloudFlare service)  whitelist. Jean-Luc Aufranc (CNXSoft)Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in […]

Resize a VirtualBox VDI Image in Windows XP/7

I had a VDI image set to 8GB that was nearly full and re-sized it to 16 GB with the following command: “C:\Program Files\Oracle\VirtualBox\VBoxManage.exe” modifyhd  “C:\Documents and Settings\Jean-Luc\VirtualBox VMs\Debian 6.0.3\Debian 6.0.3.vdi” –resize 16384 16384 is the new virtual harddisk size in MB (16 GB). This will increase the size of the Virtual disk. However, it won’t increase the size of the partition in your virtual disk. You have then 2 solutions: Create a new partition with the extra free space Use Gparted Live ISO image to increase the size of your current partition. Jean-Luc Aufranc (CNXSoft)Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011. www.cnx-software.com

Color Converter for Nokia Symbian Anna / Belle

I’ve developed a small Qt Quick application called ColorConv that can convert RGB color to HEX color used in HTML pages (e.g. 255,255,255 -> #FFFFFF) and vice versa mainly to play with Qt Creator QML and test Nokia Ovi Store application submission process. You can enter the Red, Green, Blue values manually by typing with the default numerical keypad in Symbian or use the slider to select the value. Alternatively you can enter the hexadecimal code to get the RGB value. If you are interested, you can download it in Ovi Store and in case you have some requests please comment on the support page. Nokia Ovi Store Submission Process Nokia submission process is almost free (1 Euro) and it took about 2 weeks to get my application published. I basically followed the instructions given on submit Qt applications to the Ovi Store PDF. The first thing you have to […]

How to Access the Old Youtube Layout (December 2011)

YouTube has recently launched a new version of the website with a new layout. There are several things I do not like, but the main annoyance is that apparently I can not remove the videos I have already watched from the feed. If you are like me and prefer the old layout, you can do so by accessing: http://www.youtube.com/index_ajax. It seems to work fine showing your subscriptions and friends activities, but it just displays “Authorization Error. ” at the top. I have not found any problem for now, but it’s possible that a few things do not work. Jean-Luc Aufranc (CNXSoft)Jean-Luc started CNX Software in 2010 as a part-time endeavor, before quitting his job as a software engineering manager, and starting to write daily news, and reviews full time later in 2011. www.cnx-software.com

ARM Unveils 64-Bit ARMv8 Architecture

ARM has just disclosed the technical of the ARMv8 architecture (to selected partners), featuring 64-bit instruction set support, extended virtual addressing, and backwards-compatible 32-bit support, so that software designed for ARMv7 (Cortex-A family) cores will run on the ARMv8 architecture. Here are the key points of the press release: The ARMv8 architecture consists of two main execution states, AArch64 and AArch32. The AArch64 execution state introduces a new instruction set, A64 for 64-bit processing. The AArch32 state supports the existing ARM instruction set. The key features of the current ARMv7 architecture, including TrustZone®, virtualization and NEON™ advanced SIMD, are maintained or extended in the ARMv8 architecture. … In support of the introduction of the ARMv8 architecture, ARM is working to ensure a robust design ecosystem to support the 64-bit instruction set. The ARM compiler and Fast Models with ARMv8 support have already been made available to key ecosystem partners. Initial […]

Delete Old Revisions to Reduce Time to First Byte for WordPress Blogs

I’ve already implemented several steps to improve this blog performance: Install W3 Total Cache plugin. Register to CloudFlare CDN to reduce the load on the server. Those two work pretty well, but there was still a problem with the Time to First Byte according to http://www.webpagetest.org. It got an F mark for First Byte Time. Sometimes I would get TTFB (Time To First Byte) of 20 seconds and more. TTFB is synonym of slow back-end processing either because of poorly optimized software or insufficient hardware specs or both. Part of the problem is probably due to my hosting provider (I use a shared hosting) and I sometimes get very high server load in CPanel (e.g. 50 (4 cpus)) whether my blog is running or not. But I found a blog post explaining how to try to reduce the TTFB for WordPress blog by installing Better Delete Revision plugin in order […]

Disable Auto-Update for Thunderbird and Firefox

Mozilla has decided to speed up the release cycle of Thunderbird and Firefox. This is all good except that it often breaks Add-ons. If you want to do the update manually, when you feel like it or when you know the all important plugins you use are compatible with the new version,  you may follow the instructions to disable automatic update of Thunderbird and Firefox. Disabling Automatic Update in Firefox Type about:config in the address bar and press Enter. You should get a page trying to scare you off with a message starting with “This might void you warranty!”, just click “I’ll be careful I promise!“. Then in the Filter filed type app.update.enabled. It should be set to true, double-click on the line to set it to false. Disabling Automatic Update in Thunderbird On the top menu, click on Tools->Options to enter the Options window, then click on Advanced and […]