A Non-Traditional Way Of Stress-Testing Hard Drive Arrays

Tremendous amounts of computing are now moving to the cloud. Those of us old enough to remember not just before the Internet, but before the personal computer, may remember that the cloud used to be called "mainframes." Like mainframes, the modern server farms that make up the cloud have unusual problems sometimes: here, engineer Brendan Gregg demonstrates how to reproduce one failure condition that you're not likely to run into at home.


Brendan has his own writeup of the error, which shows the diagnostic screens more clearly.

It's important to remember that even though computers are deterministic, they're still complicated enough that a given error can come from wildly improbable causes. The reason that we need monitoring systems is to observe errors as they happen, and to be able to to try and prevent them, even if we can't directly look at the underlying cause. Monitoring and testing let you answer the "what's happening?" question without requiring that you answer the "why is it happening?" question.

Five Things You Need To Test In Your iOS 5 App

At this week's Apple Worldwide Developers Conference, Mac OS X Lion, iOS 5, and iCloud are debuting, and they all look astonishing. The new services that Apple is offering are handing developers one enticing possibility after another with their new APIs. The possible apps that can be built on those APIs are amazing, and yet it'll take a lot of work to get from here to there. It's easy to get caught up in how cool the possible apps are and to overlook some of the questions that have to be answered in order to make an app that fully lives up to the promises of the iOS 5 APIs. So in order to help you get from API to all-star app, here are five aspects of an iOS app that should be on your list of things to test.

• What happens to your app when the device doesn't speak English?

  
  

Technology Advisory: Flash Player 10.2 Beta

Flash Player 10.2 beta has been released by Adobe and can be downloaded here.

The video above demonstrates one of the key new features to this Flash build, called Stage Video hardware acceleration. According to Adobe's website, Stage Video is

A new method for video playback in Flash Player that will allow developers to leverage complete hardware acceleration of the video rendering pipeline, enabling best-in-class playback performance. Stage Video can dramatically decrease processor usage and enables higher frame rates, reduced memory usage, and greater pixel fidelity and quality.

Other new features to this Flash Player build include:

• IE 9 hardware accelerated rendering support
• Native custom mouse cursors
• Full screen support for multiple monitors

Full details of this build can be found on Adobe's website, here.

How to restore iPad or iPhone with iOS 4.2 Beta version

Problem:
A connect to iTunes prompt is displayed instead of home screen in your iPhone or iPad device after installing iOS 4.2 Beta version.

When you connect the device to iTunes, message "The software on the iPhone has expired and you must be updated to a new version." is displayed.

When you try to update, message "This version of the iPhone software is the current version." is displayed but the home screen of the device is still not showing up.

When you try to restore, message "There was a problem downloading the software for the iPhone (or iPad). The requested resource was not found." is displayed.


Solution:
There are 2 ways to restore to the official iOS 4.2 version. Both would erase all your data and media files so you need to resync your device to iTunes afterwards.

Restore using an ipsw file.
1. Download the official iOS 4.2 ipsw file from the following links
http://appldnld.apple.com/iPad/061-9857.20101122.VGthy/iPad1,1_4.2.1_8C148_Restore.ipsw
http://appldnld.apple.com/iPhone4/061-9858.20101122.Er456/iPhone3,1_4.2.1_8C148_Restore.ipsw
2. Connect device to iTunes.
3. Close any message displayed.
4. Hit key and press Restore button simultaneously.
--Observe: Choose a File: iTunes dialog displayed.
5. Navigate to the directory where ipsw is downloaded to.
6. Select the ipsw file and press Choose.
iTunes will restore the device using the official iOS 4.2 ipsw file.

Restore in recovery mode.
1. Launch iTunes.
2. Connect USB cable to computer but not the device yet.
3. Do a hard reset by pressing and holding down Sleep/Wake and Home button simultaneously. Ignore the switch off prompt and just keep on pressing the buttons until black screen is displayed.
5. When black screen is displayed (before Apple logo comes up), release the Sleep/Wake button and plug in the USB to the device. Keep on pushing the Home button until the recovery mode message "iTunes has detected an iPhone (or iPad) in recovery mode. You must restore this iPhone before it can be used with iTunes." is displayed in iTunes.
6. Press OK to dismiss
7. Press Restore button and follow the prompts to download official iOS 4.2
iTunes will download the official iOS 4.2 restore file which would take around 15-20 minutes. You may need to put the device back to recovery mode (repeat steps 1-6) after the download and then press Restore button again to restore to the downloaded file.

Automated Web Services Testing - An Interview With Matt Krapivner of SmartPilot Software

As more and more companies face decisions about automating their testing, it's important to understand some of the pitfalls of automation and explore methods that avoid those pitfalls. Likewise, we need to find mature open source testing tools that help bend the test automation curve in the right direction. In previous articles, we've written about model-based and keyword-driven testing, each promising to reduce test automation script maintenance costs while increasing effectiveness (coverage). As I've searched for answers in this areas, I've sought examples of how others have approached test automation as a way of benchmarking good ideas. Recently, I've had the good fortune to meet a practitioner who has pursued new and more effective approaches to test automation. His name is Matt Krapivner and his consultancy business has provided a very impressive test automation framework to a local Web 2.0 company.

We interviewed Matt recently and talked to him about the new approach he's using with his current client and how it's a step up from traditional test automation practices.

Understanding The Differences Between Testers And Developers

Are testers from Venus and developers from Mars? In an ACM article titled An Exploratory Research Study on Interpersonal Conflict between Developers and Testers in Software Development, the authors look at the difference between testers and developers.
As stated in the article, the goal is to better understand the differences between thse two actors in order to produce better software. The authors' call to action is based on two reasons:

1. Because of a trend toward more agile software development, testers are in contact with developers earlier and more often
2. Conflict can have negative consequences not only in relation to the end product but also in relation to the job satisfaction of both developers and tester

This paper points to studies that clearly separate testers from developers in terms of their goals: developers seek to maximize efficiency while testers are all about effectiveness. Developers seek to do get their work done with the least effort while testers seek the highest quality.  Those are clearly different goals that can easily create conflict if each group sub-optimizes. Unless upper management reconciles these different goals and helps align them to reach the broader objective of the company, failure may ensue.

How Much Is Your Offshore/Outsource Testing Defect Find/Fix Cycle Costing You?

Update:  Linda G. Hayes, who is the CTO of Worksoft, Inc., and the founder of three software companies including AutoTester, the first PC-based test automation tool, wrote an interesting article on this subject at StickyMinds.com.  She wrote about the "promise of the same value proposition" and outlined some key factors for success or failure with offshoring.  One of the more interesting, and relevant comments (at least as it pertains to this article), was on "Time to Value".  Linda said:

Offshore resources are never a quick fix, especially for testing. A 2005 report from AMR Research found that it took between fourteen months and three years before the offshore testers had sufficient familiarity to be effective in finding the root cause of problems. Others have found that the lack of domain knowledge resulted in spurious defects being reported that actually increased development overhead due to review and response times. In fact, one organization identified that as many as 33 percent of reported issues were traceable to tester error.

There are many reasons to involve external testing services. Sometimes companies need the expertise of an interoperability lab, other times they are attempting to reduce testing staff costs. Whatever the reason, one cost that should be calculated based on a known process is the Find/Fix Cycle Cost for defects. It's important to evaluate these costs not just based on the hourly rate of the offshore/outsource testing service provider, but on the total cost involved in finding and fixing defects. Ultimately, this cost involves all QA and developer resource costs.

iPhone Development Basics - Memory Management Part 5

This week is the final video from Mark Johnson on iPhone memory management. In case you missed any of the previous videos, here's a list of the articles we've posted with Mark's first 4 memory management videos:

iPhone Development Basics - Memory Management Part 1
iPhone Development Basics - Memory Management Part 2
iPhone Development Basics - Memory Management Part 3
iPhone Development Basics - Memory Management Part 4