Solid-state disks offer 'fast erase' features
- — 10 February, 2009 10:13
In contrast, SiliconSystems' fast-erase feature requires power, but disconnecting the drive won't kill the process: Erasure continues the instant that power is restored. "There's no way to stop it," says Handy. The technology can be applied to the whole drive or a preconfigured secure "zone" on the SSD that's also protected by a password.
SiliconSystems also offers an SSD self-destruct feature that applies an "overvoltage" to each of the flash chips, physically destroying them. The destruction can be triggered via software or a physical switch, says Drossel. SSDs can also be designed to self-destruct or erase if they are stolen and inserted into any unauthorized machine.
In the private sector, rapid-erasure techniques could be used in point-of-sale systems or kiosks that might contain sensitive customer or sales data. "The data may be gone, but at least it's not in the wrong hands," Drossel says.
More Costly Recovery
The flip side of the level of security SSDs offer is the fact that recovering data from them can be more difficult and expensive than for other media.
Each SSD vendor has its own proprietary method for mapping data from the file system to individual memory cells. "If you don't have the mapping table that records where everything is kept, you have random data distributed throughout the chips," says Bowen. "Everyone follows their own data-placement schemes. Without knowing the details of that, it would be next to impossible to piece all of that together."
That may be true for a hacker, but not for data recovery specialists, who can pull data even when an SSD has sustained physical damage. "Kroll Ontrack has developed methods to recover data without the controller chip available," says Barry. "We've been successful in discovering a number of data layouts for different manufacturers."
Another drawback is that data on SSDs can be far more costly to recover in the event of a physical failure, such as a broken circuit. "When an SSD becomes damaged, it's more difficult to get the data off the raw chips. We've had jobs go as long as three or four months," Barry says. Costs go up if the data is needed quickly and additional staffers are assigned to the project. "That jumps up the service level," he says, "and they pay accordingly."
WinTel and SSD
In the future, changes in how the Windows file system interacts with SSDs may improve both security and performance for end users. Today, when a user deletes a file on a Windows computer, the file system removes the pointers to the locations on disk where the data that makes up the file resides, but the data itself remains until the space is allocated to another file. Only then is it overwritten. That's why erased files can be recovered on hard disk drives, and SSDs operating under Windows are no different. But that may be about to change.