The last of the independent CDP (continuous data protection) players has disappeared, after replication software provider Double-Take, purchased CDP supplier TimeSpring.

Replication software copies disk writes on a source server to a second server so that if server number one crashes, server number two still has the data. CDP software copies every byte written to disk to a second system so that not a single byte of data is lost.

Where replication is typically used by systems people to recover from a server crash, CDP is for users to recover from file deletion or corruption. By combining CDP with replication you get improved data protection with the ability to roll back your server's data to any specific point in time which could be just before a system crash or virus infection.

The TimeSpring product is Microsoft application-aware to an extent and users can recover not just files, but application items such as calendar appointments, Outlook tasks, mail messages or mail boxes from Exchange, and SQL databases. They can also drag and drop items from an older version of their SharePoint site to a newer one.

TimeSpring is the last CDP vendor which hasn't been bought by, or received investment from, a major storage vendor. The list goes like this:-

- Alacritus - bought by NetApp in 2005
- Kashya - bought by EMC in 2006
- Mendocino - received strategic investment from HP
- Revivio - bought by Symantec in 2006
- StoreActive - bought by Atempo in 2006
- XOSoft - bought by CA in 2006.

CDP technology began life as a niche technology which rapidly became mainstream. When Microsoft introduced its near-CDP product, Data Protection Manager, in 2005, the writing was on the wall for independent CDP vendors and five had been acquired by the end of 2006.

Mendocino is technically still an independent CDP supplier but it has had investment from HP and has pursued distribution arrangements with major vendors such as HP, EMC (before the Kashya purchase), IBM and Sun. TimeSpring didn't achieve that blue chip level of distribution and the acquisition can be seen as TimeSpring bowing to the inevitable and realising it can no longer go it alone.

TimeSpring CEO Rick Carlson, said: "We are thrilled that Double-Take Software has selected us to extend its protection and recovery portfolio," indicating that Double-Take first approached TimeSpring.

Double-Take CEO Dean Goodermote said: "Double-Take Software is excited to be adding the Montreal-based company's employees to its roster. TimeSpring's engineering expertise, specifically in the area of file systems and application level recovery, fits extremely well into Double-Take Software's core capabilities as does its product design into our architecture."

Double-Take has been energised under new management and is ramping up its offerings following a successful IPO. Its products already support VMware virtual servers and it has worked with Yosemite Technologies to bring remote offices and notebook computers into the scope of its products.

The all-cash acquisition amounted to $8.3 million.