QuickTip: Cold Boot iPod Nano

Chances are that you have struggled with a situation where the iPod Nano just hangs and does not take any input. One of the options is to let the battery drain.

The other option is to cold boot the iPod. For that

1. Hold the Menu and Center key for approx 10 seconds.
2. You should see the Apple logo appear and the iPod should re-start.

Enjoy!

QuickTip: Setting HTTP Proxy for SVN

For setting the HTTP proxy for SVN the regular setting of http_proxy environment variable would not work.  i.e.

export http_proxy=http://my-proxy-server.com:8080/ would not work.

There is a “servers” file in svn which is present at the following location

Win : C:\Documents and Settings\hazrativ\Application Data\Subversion\servers

Linux: /etc/subversion/servers

Here you need to set the proxy server and port settings so that command line SVN can access the external world form the proxy. Uncomment and change the lines necessary

[global]
# http-proxy-exceptions = *.exception.com, www.internal-site.org
http-proxy-host = myproxy.us.com
http-proxy-port = 8080
# http-proxy-username = defaultusername
# http-proxy-password = defaultpassword
# http-compression = no
# http-auth-types = basic;digest;negotiate
# No http-timeout, so just use the builtin default.
# No neon-debug-mask, so neon debugging is disabled.
# ssl-authority-files = /path/to/CAcert.pem;/path/to/CAcert2.pem

If you get something like

svn: C:\Documents and Settings\hazrativ\Application Data\Subversion\servers:73:
Option expected

then it means that you have a space at the start of the property which you have un-commented. Make sure that there is no space in the beginning of the property in the servers file.

Active Versus Passive Exception Handling

Exception handling is an important tool. The effective use of this tool would help in improving the reliability and availablility of the system.

Reliability is termed as the probability of failure-free software operation for a specified period of time in a specified environment. With good exception handling the system would be able to take corrective action and/or take an action which would ensure that the software will not fail.

Availability is defined as the uptime and is inversely proportional to the downtime and the recovery time. Good exception handling would ensure that if there is a failure then the problem can be isolated quickly and the recovery time is fast.

Thus effective exception handling would help both the reliability and availability of the software.

Lately there has been the much desired shift towards unchecked exceptions. Earlier, the client code had to catch a number of exceptions even though there was little that the client could do in scenarios such as programming errors or resource related errors.

What do you expect the client to do when the database is down? The best way would be to throw an unchecked exception through your layers and finally the presentation tier would deal with it so that the end user can see a relatively decent message on the screen.

Exception handling can be further classified into Active and Passive

• Passive Exception Handling is when the exception is logged onto a file. Now the message would remain there unless someone looks at it and then acts upon it.

• Active Exception Handling is when the exception message is pushed across for attention. An example would be to page the person or email the support group when an exception occurs. This push sends the message to the radar of concerned people/systems rather than waiting in a log file to be acted upon.

For critical pieces of the software it is essential that a strategy which combines active and passive exception handling is considered so that any failure is immediately looked upon so that recovery is faster. The reliability would also be higher as with active exception handling the faults would be potentially contained before they become failures.

How does Oracle GUID work?

I was having a discussion with my colleague this morning about the guarantee that Oracle GUID would be unique on multiple horizontal stacks that we are deploying our application to.

My understanding is that for generating Pseudo random numbers you need to have some seed to start with, I was wondering what seed does GUID use to ensure that it is mathematically unique. Following is the answer that I discovered on the net.

“A Globally Unique Identifier or GUID is a pseudo-random number used in software applications. Each generated GUID is “mathematically guaranteed” to be unique. This is based on the simple principal that the total number of unique keys (2^64) is so large that the possibility of the same number being generated twice is virtually zero.

SYS_GUID generates and returns a globally unique identifier (RAW value) made up of 16 bytes.

On most platforms the generated identifier consists of a

• host identifier,
• a process or thread identifier of the process or thread invoking the function,
• and a non-repeating value (sequence of bytes) for that process or thread.

Software Releases and Sustainable Pace

Several times we all have been in situations where there is a lull period in the product life-cycle. This is when the team is not being pressurized by the product owner to spew out releases because in turn marketing is not ready to push out external releases to the customer. This usually saps out the energy out of the Agile team and is against the principle of Sustainable Pace.

The Agile team should work on a sustainable pace and keep churning out production worthy internal releases. Marketing and business then have the opportunity of picking up the one that they want to promote to the external world.

Assume that you have created internal releases (IR)  like this

• IR1 – Product + F1, F5, F6
• IR2 – Product IR1 + F4, F9, F15
• IR3 – Product IR2 + F6.1, F12, F10
• IR4…n

Top Posts of 2008

This weekend I decided to do some analysis on the blog hits for 2008 and here are the results

The top posts of 2008 averaging 2775 hits amongst themselves were, with the highest being 4391.

• QuickTip : How to increase the Java heap memory for Maven 2 on linux
• QuickTip: Resolving Bluetooth Issues With Ubuntu 8.04 LTS
• DBUNIT : Extracting Test Data into XML file
• QuickTip: JUnit: The input type of the launch configuration does not exist
• QuickTip : Spring 2.0 testing: java.lang.NoSuchMethodError

The top referred article posts were