Aleksandar's computer workshop
Let's see what Aleksandar was fixing today.
My findings, tips & tricks related to computers, internet, programming and other stuff I was working with.

Best way to practice and learn how to manage complex networks

November 29, 2010 22:43 by Aleksandar

Just use GNS3!

GNS3 is a graphical network simulator that allows simulation of complex networks.
To allow complete simulations, GNS3 is strongly linked with :

  • Dynamips, the core program that allows Cisco IOS emulation.
  • Dynagen, a text-based front-end for Dynamips.
  • Qemu, a generic and open source machine emulator and virtualizer.

GNS3 is an excellent complementary tool to real labs for network engineers, administrators and people wanting to pass certifications such as CCNA, CCNP, CCIP, CCIE, JNCIA, JNCIS, JNCIE.

It can also be used to experiment features of Cisco IOS, Juniper JunOS or to check configurations that need to be deployed later on real routers.

This project is an open source, free program that may be used on multiple operating systems, including Windows, Linux, and MacOS X.

Features overview

  • Design of high quality and complex network topologies.
  • Emulation of many Cisco IOS router platforms, IPS, PIX and ASA firewalls, JunOS.
  • Simulation of simple Ethernet, ATM and Frame Relay switches.
  • Connection of the simulated network to the real world!
  • Packet capture using Wireshark.

Some usefull links:

A lot of documentation and video tutorials http://www.gns3.net/documentation

Download page http://www.gns3.net/download

 


Fixing power connector on ASUS M6000 (M6N) laptop

April 6, 2009 00:48 by Aleksandar

Today I got ASUS M6N laptop for repair. It did not want to turn on and also it does not give any sign that it’s charging the battery.

Laptop was previously sent by it's owner to ASUS repair center and paid 70 EUR only for diagnostics. ASUS came up with 600 EUR bill for repair so owner did not accepted the offer. They suggested motherboard and HDD replacement (?!). I did not understand why HDD because HDD works just great.

Anyway, laptop finished at my place and after 1.5h work laptop is working again! It needed some dust cleaning and bit soldering...

First I had to find disassembly or service manual. Bit of Googling and visiting some favorite sites I found the manual here
http://1toppc.com/Merchant2/images/Notebook/Assembly/M6A_V-Chapter%2003-v1.1.pdf

After laptop is taken apart I made these pictures (click on image for high resolution):

CPU and surrounding covered with dust.


Loose broken power plug and very dirty fan


Again broken plug after I have "shaked" the laptop a bit. Now you can also see the rest of the power connector.


Bigger picture of the open case and power connector location



Here is the "guilty" part



Which came out from here... Good luck that motherbord and othr parts are not affected with accident


After operation it looks like this. Metal part is soldered properly to the motherboard.
I have melted together top part of the connector case to assure better joint.


As you can see everything is clean and neat again.


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R4DS SDHC - how to resolve missing games, files or strange folder names

March 11, 2009 02:20 by Aleksandar

If you have Nintendo DS and using R4DS SDHC (clone of popular R4DS but with SDHC cards support) you might face some problems in case you are using SD card bigger than 2GB.

You might face following simpoms:
* you can't start-up the moonshell or it freezes on load.
* If you have more than 25 files in one folder and you select the folder in the file browser you DS will freeze
* If you have more than 70-100 files on the SD(HC) card some games are not listed or folders are showed as chineze writting
* If card (I had problem with 8GB) is almost full (more than 150 games) you might "loose" the theme icons

New firmware upload and "plain" SD card format in Windows will NOT help.

In order to fix the problem you have to do following:

* Make backup of your SD card
* Download the SD Memory card formatting software from this link http://panasonic.jp/support/global/cs/sd/download/sd_formatter.html
* Follow the instructions as described here http://panasonic.jp/support/global/cs/sd/download/ftp/SDF_manual.pdf and format the SD card. Be sure you have selected FULL (ERASE ON) and Format size Adjustment is ON
* When format is done. First copy the R4 firmware (files in root, _system_ and moonshl folders) and then create one folder called Games. Create several subfolders and place up to 20 games per subfolder.
Here is sample folder structure.

Trick is in special software for SD memory formatting. This cloned version of R4 is sensitive to "dirty sectors" on SDHC card bigger than 2GB.

Hope this will help you out as it did help me.

Usefull links:

SD Memory Card Formatting Software
http://panasonic.jp/support/global/cs/sd/download/sd_formatter.html

Cannot get all R4DS Games to show...
http://www.r4ds-forums.com/viewtopic.php?f=50&t=2571

Alternative R4DS Firmware: YSMenu (with automated builders)
http://www.r4ds-forums.com/viewtopic.php?f=16&t=1957

Using YSMenu on an R4 Clone
http://www.r4ds-forums.com/viewtopic.php?f=54&t=2377


How to enable AHCI mode after installing Windows

February 20, 2009 21:01 by Aleksandar

AHCI (Advanced Host Controller Interface) is present on newer Intel chipsets such as 975X (ICH7), P965 (ICH8), and P35 (ICH9). AHCI mode is enabled in the BIOS and 3 settings are commonly available: IDE, AHCI, and RAID. The last two (AHCI and RAID) require a driver floppy and the F6 method when installing Windows XP otherwise the hard disks won't be detected.

AHCI mode brings 3 main advantages:
Supports NCQ (Native Command Queuing) allowing SATA drives to accept more than one command at a time and dynamically reorder the commands for maximum efficiency.
Supports hot plugging of devices
Supports staggered spin ups of multiple hard drives at boot time

However, in the real world the performance difference isn't huge.

The problem is that if you installed Windows in IDE mode (i.e. you didn't use F6 and supply a driver disk), then simply changing the BIOS setting to AHCI mode and rebooting will cause Windows to fail and will require a repair install. Most people have been advising to reinstall Windows if you want AHCI enabled.

Here you will find the sollution :

http://forums.pcper.com/showthread.php?t=444831

Copy of the article is here (5.07 kb)