A week ago I had a hairy crash when stopping ZFS/FUSE on my box, which I mentioned on the ZFS/FUSE mailing list. I upgraded from 220.127.116.11 to 2.6.26-rc7 and in the process blew away the kernel build tree for the 18.104.22.168 kernel to recover the disk space. Shortly after that I received a query off-list from Miklos Szeredi, the FUSE maintainer, asking if I could supply him a disassembly of the offending function from the kernel build – which was now consigned to the bit bucket. 🙁
Fortunately I’ve been regularly rsync’ing various important parts of my computer onto ZFS/FUSE partitions and snapshoting them with timestamps so I (theoretically) was only a few commands away from getting to the defunct kernel tree once more. The problem is that unfortunately you can’t look at a ZFS/FUSE snapshot directly at the moment, it’s one of the parts that is still to be gotten working under Linux.
A clone is a writable volume or file system whose initial contents are the same as the dataset from which it was created. As with snapshots, creating a clone is nearly instantaneous, and initially consumes no additional disk space. In addition, you can snapshot a clone.
The magic command to do this was just:
zfs clone ZFS/home@20080606-2201 ZFS/temp
and suddenly I had /srv/ZFS/temp, a fully working version of this machines /home directory as it was around 10pm on the 6th June and in it was the kernel tree.
If you attempt to compute a single hash on an entire card, you won’t get any improvement. Same as you wouldn’t if you tried it on a single vs. quad core CPU. But if you compute four hashes, than single vs. quad makes a huge difference. And the GPU cards are effectively 128 core CPUs, so when you need to compute millions of hashes…
One way of visualizing this is noting that a single 8800 Ultra could brute-force break an MD5 hashed password of eight or less characters+numbers (A-Z, a-z, 0-9) in about ~16 days.
But this really is just a quick hack:
The MD5 code used here was written in less than 2 days, as a proof-of-concept, and with only a single one-liner GPU-specific optimization.
Of course if people do want to try playing with it the program is available, though at the moment there isn’t a software license included with it. I’ve emailed Mario about the license to see if he can clarify what the rules are.
If, like me, you’re curious about how petrol prices vary across the world then this handy site has a nice table made up from information from contributors around the world (and they want more). The figures are normalised to USD per gallon and Indian Rupees per litre (and be aware of the caveats at the end).
Interesting to see that whilst Americans complain about the cost of petrol they still pay less for it than Australians were in 2005 and presently the UK pays 2.5 times the price of gas in the USA.
Top secret – The compromise of this information or material would be likely: to threaten directly the internal stability of the UK or friendly countries; to lead directly to widespread loss of life; to cause exceptionally grave damage to the effectiveness or security of UK or allied forces or to the continuing effectiveness of extremely valuable security or intelligence operations; to cause exceptionally grave damage to relations with friendly Governments; to cause severe long-term damage to the UK economy.
OK, so maybe you’ve got a few hundred, or thousand, photos that you’ve taken, but how do you search them ? You could try and tag them for everything (if you’ve got the time) but wouldn’t it be nice if you could just draw a picture and search for that ?
Well the Digikam folks are working on that by incorporating some of the existing ImgSeek projects code into the KDE4 version of Digikam (0.10.0).