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Comment: Re:Intentional (Score 1) 148

by meadowsoft (#46648725) Attached to: Russian GLONASS Down For 12 Hours
From Wikipedia again:

"...it happened in 2000 once the U.S. military developed a new system that provides the ability to deny GPS (and other navigation services) to hostile forces in a specific area of crisis without affecting the rest of the world or its own military systems."

Perhaps the US is using such a system actively in the Ukraine region.

Comment: Re:Down? Or encrypted? (Score 3, Informative) 148

by meadowsoft (#46648685) Attached to: Russian GLONASS Down For 12 Hours
It is called selective availability. http://en.wikipedia.org/wiki/Selective_availability#Selective_availability My undergraduate thesis involved how to couple intertial senors using a Kalman filter to compensate for SA in GPS signals. Two years after my project concluded, the US disabled SA in GPS. I doubt that this recent "outage" was related to similar SA in GLONASS. Rather, perhaps it was indeed an encrypted transmission, or was based on a second independent synchronization signal only available to military assets used to put the scrambled transmissions back in the right order.

Comment: High degree of false positives (Score 1) 652

by meadowsoft (#29995200) Attached to: Iraq Swears By Dowsing Rod Bomb Detector
Since you can pretty much hit a landmine by walking into a random patch of Iraqi desert and throwing a rock, I don't find it surprising that any land mine sensing divining rod would have at least some random chance of success. I think that past research has shown that any tool that is picking arbitrary points on a grid will find positive results for "hidden" items (explosive or not) with a frequency of occurrence that matches the normal distribution. I encourage you to read The Drunkard's Walk by Leonard Mlodinow for a better description than I can give.

Comment: Zanac anyone? (Score 2, Informative) 404

by meadowsoft (#29732473) Attached to: Should Computer Games Adapt To the Way You Play?
I seem to remember in the promotional materials for the NES game Zanac (by FCI) that the game was supposed to get dynamically harder the better you played. When I was playing, I specifically remember this being the case, and that I enjoyed the game more as a result. I used to be able to play straight through to the 10th (out of 13) levels without dying once, and then I would die multiple times in a row. As if sensing my desparation the game would scale back the number of baddies it was throwing at me, and then I could regain my footing, collect some powerups and move on. Then the game would throw more and more at me until I got to the unholy nightmare 13th level.

Time to go dust this game off on the Wii...
The Courts

Court Orders Breathalyzer Code Opened, Reveals Mess 707

Posted by timothy
from the take-a-sober-look-at-this dept.
Death Metal writes with an excerpt from the website of defense attorney Evan Levow: "After two years of attempting to get the computer based source code for the Alcotest 7110 MKIII-C, defense counsel in State v. Chun were successful in obtaining the code, and had it analyzed by Base One Technologies, Inc. By making itself a party to the litigation after the oral arguments in April, Draeger subjected itself to the Supreme Court's directive that Draeger ultimately provide the source code to the defendants' software analysis house, Base One. ... Draeger reviewed the code, as well, through its software house, SysTest Labs, which agreed with Base One, that the patchwork code that makes up the 7110 is not written well, nor is it written to any defined coding standard. SysTest said, 'The Alcotest NJ3.11 source code appears to have evolved over numerous transitions and versioning, which is responsible for cyclomatic complexity.'" Bruce Schneier comments on the same report and neatly summarizes the take-away lesson: "'You can't look at our code because we don't want you to' simply isn't good enough."

Comment: Re:striped? (Score 2, Insightful) 274

by meadowsoft (#27589251) Attached to: First Look at Microsoft Exchange Server 2010 Beta
This is not unique to Microsoft products. Databases have been doing this for a long time. Oracle Database has options for RAW devices and disk access, where redundancy is handled in the application layer by throwing more disks at the problem. You can also stack your layers of redundancy by using Oracle automated storage management to have multiple logical disks while at the same time using an array controller to provide a level of RAID redundancy at the physical layer.

And a point about JBOD being useful for Exchange. In most Exchange environments I have worked with, replication happens at the appication layer, with huge portions of the data store being replicated amongst members of the Exchange Cluster, each with their own copy of the data. While expensive RAID/physical redundancy is a good idea, it is not critical as exact copies of the data store are available elsewhere in the cluster, and mailboxes can be failed over to those members.

And for the people that want a full RDBMS or SQL Server under the hood of Exchange - this is primarily a performance concern. Exchange access to data stores has such a unique profile that ca be modeled to show specific performance profiles that would benefit from a customized data access layer, overall Exchange performance would be hampered by the inclusion of an RDBMS that was designed to respond to a multitude of performance profiles. When you have the luxury of understanding how your application accesses data, it is best to choose (or develop) the data storage subsystem that will reap you the best performance. Here is where I believe Microsoft has the right approach.

Comment: Whither OCFS? (Score 1) 272

by meadowsoft (#27303547) Attached to: Reasonable Hardware For Home VM Experimentation?
Any reason you want to go down the (multi)path of OCFS for a 3-node Oracle RAC? Why not just use RAW shared disks? You aren't going to see the difference in a virualization environment anyhow - your disk bottleneck will be the shared access in the Virtual disk controller. OCFS is really only useful when using real HBA's for FibreChannel or iSCSI.

And don't forget to select "Enterprise Edition" when doing your Oracle install. Standard has a 2-node limit.

Comment: Re:Pure speculation... (Score 1) 64

by meadowsoft (#27068165) Attached to: Meteorite Hunters Find the West Texas Fireball

Unless the asteroid in question is small enough that it falls into the "OMFG HOW DID WE MISS THAT?!?! WE'RE DOOMED!!!" category. I can have a small asteroid knocking on our doorstep (a few hundred thousand kilometers, astronomically speaking) and still not be able to see it with the vast majority of instrumentation in our arsenal today.

Logic is a systematic method of coming to the wrong conclusion with confidence.

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