According to a recent Reuters news release, Nasdaq OMX Group has completed software changes to the system that caused a three-hour stoppage in trading last summer with hopes of limiting the length of future outages the system may experience.
When the software glitch struck the Nasdaq-run Securities Information Processor (SIP) in August, investors who did not subscribe to the exchanges’’ proprietary data feeds were left uninformed of critical stock information. To maintain a fair market, the exchange shut down trading in its listed securities for hours, initiating concerns among traders.
Brian Hyndman, Nasdaq's senior vice president of global information services, indicated in the article that technical outages are expected from time to time but the amount of time it took the system to get the market back up and running was alarming. Software changes have been made to correct these issues and will hopefully improve uptime of the system. Hyndman added, "It's not perfect - there are risks with any system - but by the end of this month, if we do have an outage, we feel like we can be back in a fairly short amount of time."
Executing system tests alone on application such as the ones running in the Nasdaq system will likely not result in 100% coverage. Many of the functions often contain error handling code that’s very difficult to stimulate using the fully integrated application. Software developers and those individuals that are responsible for business-critical systems like Nasdaq, should also perform unit and integration testing to ensure high code quality.