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It was not a banner week for cloud computing. Cloud computing rivals Google (NASDAQ:GOOG) and Microsoft (NASDAQ:MSFT) suffered brief outages that knocked off some of their key messaging and collaboration products.

Google Sept. 7 saw its Google Docs word collaboration application cramp up for one hour, shutting out millions of users from their document lists, documents, drawings and Apps Scripts. Microsoft, meanwhile, watched its online services, including Hotmail, SkyDrive and Office 365 software, go kaput for three hours Sept. 8.

Google’s outage was caused by a memory management bug software engineers triggered in a change designed to "improve real time collaboration within the document list," the company explained in a corporate blog post.

That’s the simple explanation. Google Engineering Director Alan Warren provided more technical detail for the outage in the blog post, noting:

"Every time a Google Doc is modified, a machine looks up the servers that need to be updated. Due to the memory management bug, the lookup machines didn’t recycle their memory properly after each lookup, causing them to eventually run out of memory and restart. While they restarted, their load was picked up by the remaining lookup machines–making them run out of memory even faster."

Pounded by such heavy usage, the servers couldn’t effectively process most of the requests to access document lists, documents, drawings and scripts. Thus, the outage occurred. Warren said his team has taken steps to eliminate the chance of a similar event in the future.

Microsoft’s outage was more serious. Beginning around 9:30 PDT Sept. 8, the company’s Hotmail, SkyDrive and Office 365 services went down, owing to a Domain Name System (DNS) issue. The DNS converts domain names into numerical IP addresses to route Internet traffic worldwide.

"We believe service restored for all Office365," Microsoft tweeted on its Office 365 Twitter account. "If customers are still having issues, please let us know. Thanks for your patience."

To read the original eWeek article, click here: Google, Microsoft Weather Cloud Computing Outages