Thursday, September 20, 2012

Using IOMeter

Excerpted from

The IOMeter tool can be used to test disk performance, IO transfer rate and IO response time. I used it to pump some traffic (read, write or both) in the network and measure the performance of the ports utilized and trigger threshold crossing events.

Some important points about using this tool are mentioned below:

1. Run this tool as an administrator user.

2. Select the disk targets which are generally in my case remote SAN/LAN disks presented to the host or VM on the hypervisor. You should specify the number of sectors Iometer can use for the performance test otherwise it will use all available disk space and if the disk is huge then the tool just appears to have stuck in “preparing disk”. So set the “Maximum Disk Size” to 1000 sectors as shown below.


3. You should configure the “Access Specifications”. Any pre-configured specification (like “512B; 100% Read; 0% random”) can be used for basic traffic related tests.

4. Start the performance test by clicking the green flag button on the toolbar.

5. IOMeter will prompt for specifying the results.csv file where it will log the test results.

6. Now go to the “Result Display” tab as shown below to watch the result. You can set the update frequency to 3 or 5 secs to watch the updates in real time.


7. To end the test, click the Stop button on the tool bar.

Wednesday, September 12, 2012

A simple chrome web app

To create a chrome web app follow the below steps:

1. Create a new folder.

2. Have an icon from and save the icon (PNG format one in the above folder).

3. Create a new text file and copy paste the below (the below sample creates a chrome web app to launch this blog):

"name": "Watsh's Blog",
"version": "1.0",
"manifest_version": 2,
"description": "Launcher for Watsh Rajneesh's blog",
"icons": { "128": "gnome_blog.png" },
"app": {
"urls": [
"launch": {
"web_url": ""

The highlighted parts above can be changed to create your own chrome web app.

4. Save the above file with the name “manifest.json” in the same folder we created above. The complete manifest file info is found here.

5. Now to install it in chrome browser, select the settings icon “wrench” on the top right hand corner of your chrome browser and select Tools > Settings > Extensions and check the “Develolper mode” check box. Then click on the “Load unpacked extension” and select the folder we created above which contains the icon and the manifest files.

6. That’s it. Your web app is installed and available in chrome.

The above tutorial is based on this nice tutorial. The only change I have done above is to port the manifest.json to comply with manifest file version 2.

15 sorting algorithms visualized in 5 minutes, with awesome arcade sounds

15 sorting algorithms visualized in 5 minutes, with awesome arcade sounds from r/programming