Review data Rescue 3
Friday, 12 March 2010
How does it work?
Normally, people just throw things in the trash and choose Empty Trash – this effectively deletes the path leading to the file itself, rather than deleting the file.
So the file just sits there on the hard drive, secure in its magnetic encoding, waiting to be written over by another file. This does (usually) effectively at least ruin the file, so that it cannot be recovered.
But there’s also Secure Empty Trash (below Empty Trash in the Finder’s File Menu), which does a better trashing job. Files deleted in this way are overwritten by meaningless data, which can take some time, depending on file sizes.
To go even further, you can open Disk Utility (it’s in your Applications’ folder in turn in the Utilities folder, and it’s a free Apple app) and click on a drive and ‘write zeros’, which writes zeros over ‘empty’ space, that being space on hard drives not linked to the directory structure.
So data rescue does little actual file retrieval – it’s more about restoring the pathways Unix (and then OS X) uses to let files open, and to make files open to specific applications when you double-click them.
You can do this in more and more fundamental manners, taking longer and longer of course, and I always delete files and applications and write zeros in a least one pass before I sell a Mac, or give it back to Apple if it’s a review unit.
Of course, another way you lose files is they just flicker and ... disappear. Either way, Data Rescue may be able to help.
Great recoveryData Rescue 3 claims to recover files in good condition, restoring icons, dates and even folder hierarchy. DR3 focuses on data recovery rather than hard drive repair, although the Analyze (sic) function will attempt to point out what's wrong with a drive, drawing on ProSoft's Drive Genius experience.
Data Rescue 3 sports a brand new Graphical User Interface, with animated visual effects – this is actually borrowed from Drive Genius. I don’t know why, actually – I didn’t like it myself, and said so in my review last year. It looks good, sure, but getting the icon you want is a bit like trying to grab slippery fish in a bucket. It's called Arena View, btw (pictured below), and luckily a quick click on the Detail View icon at bottom left gets rid of it for something less fun, but easier to use.
But over 100 new reconstructed file types have been added for Deleted and Deep scans and a new feature called FileIQ allows Data Rescue 3 to learn about new file types from user-supplied samples. You tell it ‘retrieve this type of data, please’ to extends the number of potential reconstructed file types supported.
A new File Previewer feature means you can preview many file types prior to recovery.
You can suspend and resume scans, and manage the results from multiple scans. Small performance increases come from improved support for scanning Apple software RAID drives, for scanning larger than 1TB drives, for recovering large sparse disk image files, recovering pkzip files and hard-linked files.
The ability to unmount or eject a volume has been added (useful when booted from the rescue DVD-ROM you can – and should – build from DR3) and there’s a New Home Folder feature when booted from DVD, which avoids the need to re-enter activation key each time it’s booted. DR3 has also had numerous bug fixes.
Timely
Apple computers have never been that crash hot (ha ha) at estimating times for tasks undertaken. Data Rescue 3 said it would take 36 hours to scan my 1TB external USB2 Seagate hard drive for deleted files, and after ten minutes, it said 32 hours. Half an hour later, it said an hour to go.
But then it went back up to 30 hours … when the scan actually finished, it was the following day – elapsed time was not recorded once the scan finished, but at least 20 hours elapsed over the USB2 connection. That was using an 8-core Mac Pro.
Using a 2008 MacBook Pro 15-inch on the same 1TB external USB2 Seagate drive, it estimated 59 hours for the same task. I started the scan at12 noon on a Wednesday; after 36 minutes 10% of the scan had been achieved, so multiplying that out, I’d expect it to take – yeah, about 54 more hours!
But try the Quick Scan first – this only took about three minutes and found a staggering amount of files I’d deleted. So if this didn’t work, imagine what a 54 hour scan would find!
I also wrote zeros with Disk Utility and then did the Quick Scan – this certainly radically reduced the amount of files DR3 detected, down to about the seven that I'd done something to or created after the zero-write.
You can use an unregistered copy of Data Rescue to scan for files, by the way. The demo works exactly as the fully licensed version would, which will allow you to see all files available for recovery. But in demo mode you can only recover a single file, and only if it's no larger than 10MB.
The manual recommends a Quick Scan first, in any event,and can work even if your drive won't mount. Do that to see if your missing files get listed, and go to the other options if they don't manifest themselves in the recoverable list.
Deep Scan uses every trick in DR3's arsenal to find every recoverable file on your HD. This may be the second option but is actually the last-resort, most-severe-cases, last resort option.
Deleted Files Scan looks for recently deleted files. It's the third option but should be used second, according to the manual.
Another option is Clone, which makes an exact copy of a drive. In theory, if you are losing files because of drive failures, those hardware errors may in turn hinder file recovery. So cloning the content to a sound drive may make those files recoverable again.
Analyze may help explain why your files are flickering, and File IQ lets you add new or unknown file types to the recovery criteria. The Quick Analyze of my 1TB Seagate occurred in just 20 seconds, presenting read times in a graph. Even the second option under Analyze took just two minutes, though.
Conclusion: On the packet it says 'Do it yourself data recovery software' and it's true, but if you want to, using the excellent manual, you really can become a data rescue expert.
What's great: Really comprehensive file scanning and recovery, plus the ability to learn new file types makes this exceedingly powerful. Coupled with a very comprehensive manual and you're potentially a hardware pathologist. Luckily, the extremely fast (comparatively) Quick Scan uncovers a surprising wealth of disappeared files.
What's not: I don't like the Arena interface. Why aren't the options available in the order the manual recommends using them? Time – you might be panicking when you begin your scan for lost files, but how will you feel 50-odd hours later? But hey, if you get your file back, that could be the best thing, right?
Requires: Time, patience and an extra hard drive to restore files to.
Verdict: Awesome.
Data Rescue 3, Prosoft Engineering, US$99 (Personal Use License cNZ$142), US$249 (Professional Use License, cNZ$356) and US$5 (Boot DVD Download if you already own DR3 and you want an updated boot DVD, cNZ$7.)
System: Compatible hardware includes all Apple computers developed in the last 3 years including G4/G5/Intel PowerBooks, MacBooks, MacBook Pros, iMacs, and desktop machines. Data Rescue needs at least 512MB of RAM to run (1GB is recommended).
A second hard drive with sufficient free space is needed for Data Rescue's workspace, and to recover files to.
Contact: Prosoft Engineering
