b. Amateur rocket activities means launch activities conducted at private sites involving rockets powered by
a motor or motors having a total impulse of 200,000 pound-seconds or less and a total burning or operating
time of less than 15 seconds, and a rocket having a ballistic coefficient--i.e., gross weight in pounds
divided by frontal area of rocket vehicle--less than 12 pounds per square inch.
If your rocket activity doesn't fall into that exception, then you need a FAA launch license or experimental launch permit, and all the associated paperwork and analysis.
These rules are driven by politics, not by sound engineering. Most of the people making the rules probably don't know enough about flying to fold a paper airplane.
Please don't go around sticking your foot in your mouth.
The anon coward a few back is an industry outsider (I have a guess who, but it's obvious from what they said that they at least know the insiders). I participated in some of the discussions leading to comments filed with the FAA about the proposed rules which are now final. I know most of the people who wrote the industry comments, and saw a number of the comments in draft form prior to submittal. The FAA AST staff who did this are also people who've come out into the community.
The industry objected to some details of the proposed rules; those objections are noted appropriately and either got changed or explained well enough that the justification is sensible, though some of us may disagree with individual pieces of it.
The rest of it was ok, with a little jockeying back and forth to optimize some of our particular operating paperwork burdens for our spacecraft designs.
Characterizing this as random government abuse of a new industry is bullshit.
The United States has a land area of about 9.6 million square kilometers; California is about 0.4 million square kilometers. The US currently uses about 19%, or 1.8 million square kilometers of land, for agriculture.
So what you're saying is that we can't possibly use 22% of our agricultural land to produce fuels. That is a claim which is... well... innumerate. Especially if your fuel of choice is methanol, which can be produced from fermenting the leftover chaff from nearly all of the rest of the agricultural work nationwide, without dedicated land...
It would take about 2 million square km of cheap amorphous solar cell to give every man, woman, and child expected to be living worldwide at the population peak in 2060ish as much electrical power as people in the US use per capita now. We can treat this as a reasonable limit case for how much we need.
The earth has a surface area of around 510 million square km.
We'd preferentially want to use equatorial waters, which limit you to about 200 million square km, but that's still only using about 1% of the total ocean surface area.
Those solar cells tend to have a similar reflectance/absorbed as heat ratio as ocean water; that heat will end up slightly more preferentially in the air rather than in the water, but that's not a huge effect. Only about 10% of the total solar energy will come out in electricity and be "lost" compared to water's thermal absorbtion.
The total impact here is not negligible but is pretty minor. We shouldn't ignore climatic issues, but they are likely to be small, and in the opposite direction from global warming's impact.
Specialization is what makes modern economies work. It's called progress--it's a good thing.
And cross-training lets you solve larger problems. If all you can do is one job, you're a worker drone. If you understand several, you can solve cross-discipline problems.
Most college students who take in $1.3 million over 2 years are doing so via drug dealing. It doesn't take a post-9/11 conspiracy seeking banker to see something suspicious there.
Apparently this was the nearly unheard of exception, but that doesn't indicate that the suspicion was unreasonable.
Normal screws the size of nails tend to fail in shear at much lower stress. This is not bullshit.
Larger screws made out of stronger alloys don't, but are typically too big to usefully stick a 2x4 to another 2x4, or hold a sheet of plywood into a 2x4 with typical installation accuracy. And require a pre-drilled hole, which at least doubles the time to install. These screws are not useful for typical building construction tasks. Cracking the wood all to hell installing oversize nails or screws incorrectly is far from the best solution.
Wood is a hard material to join really well. You can do all sorts of half-ass methods and get two pieces of wood to stick together adequately, but doing a really good job is a lot harder. Because it's got grain and fiber, you need a lot of bearing surface to avoid the connector pulling out. Screws do great at that, but have less shear resistance, and lower cost screws are too brittle and crack right off in shear (and sometimes in tension). Nails are great at shear and are made out of alloys that rarely crack, but can pull right out. Boat nails, ring nails, other stuff is out there, but this seems to be a pretty big advance in balancing the shear and tension capabilities, ease of installation, etc.
For absolute optimal strength, pre-drilled carefully sized screws work pretty well. This nail should be about as strong, but about 10% the effort to install, and probably a tenth the cost for the fastener.
There was a time that it was safe to assume that people at least had built a treehouse or some such and had a clue about basic woodworking techniques. Apparently that time is now past.
...but for anything other than programmer teams, I want my people talking and cooperating on fixing problems, and cubes, open offices, bullpens and the like work just dandy.
I do IT operations and development rather than programming, so they are different work types. Joel may be right for cutting edge programmer productivity. But I've also seen very productive very loud programmer teams in open offices.
Some programmers will do terribly in that environment, but many will either thrive on the noise or tune it out (or put on headphones).
Niagra and Niagra 2 have lousy floating point performance (1 FPU for entire chip, shared by all the cores). Given that the DARPA project is for FLOPS, Nigra is just about the worst processor one could propose for the project.
I love the Niagra design; for 90% of what I need done, it does great. It's just terrible at floating point.
Sometime down the line, past Niagra 2, one could posit a version of such a chip with enough floating point units that it's efficient in FLOPS; it's an obvious upgrade of the current chips. However, that also is not optimal for FLOPS in the HPC regime. HPC is all about hiring enough computer scientists and physicists to micro-optimize the code so that you make close to theoretical maximum efficiency in utilizing the CPU cores. Niagra is all about keeping enough contexts on the chip that you can productively use the time that normal programs spend wasted, waiting for main memory accesses and so on. HPC by definition spends the CS time and effort to avoid that already.
Hey Derek. I take the flip side interpretation of this... the basic concept is just a http://en.wikipedia.org/wiki/Farnsworth-Hirsch_fus or Farnsworth Fusor, which is known to work (you can buy tabletop neutron generators in that configuration), with a couple of major variations, including the direct ion and electron well accellerators. The reason Farsnworth Fusors aren't practical for largescale power generation is that they more or less unavoidably lose energy to ion or electron collisions with the accellerator grid, which everyone has known for decades. It's also been widely postulated for decades that some form of magnetic isolation of the grids might enable you to get around that; there were arguments that the math worked and basic physics worked in the early 1980s, for example, but nobody had any idea how to do the detailed configuration to actually build a magnetically isolated grid fusor.
Bussard was openly talking about working on magnetic isolation in the 80s and 90s but hadn't really gotten far enough for anyone to believe that it was in fact necessarily possible. Then he shut up about it, and I think that the experts conclusion was that it either didn't work or his funding had run out. Assuming he's not lying in the talk (and I sort of doubt he'd do that), the actual story was that he was funded at a low rate with a nondisclosure restriction, and it took him 11 years to work on it enough to figure out the right combination of secret configuration and ingredients sauce to make the magnetic isolators actually work. The results he describes from his last set of tests, and the test configuration he described, sound exactly like what a successful working magnetic isolator would, as far as I can tell. His physics/engineering project has wandered over to where the theoretical predictions said things might work twenty years ago, and they seem to have worked. The fundamental question all along was whether the magnetic isolators were purely a mathematical construct, or if there was in fact a workable geometry which could make them real physical entities. The answer on first inspection is that yes, there must be, because it seems like they've demonstrated one.
Now that he's described it... I've looked into this myself in the past, considering building a conventional electrostatic Farnsworth Fusor just for fun, and it seems really credible. I think he's right that a demonstration unit at low power would answer the question conclusively, with only a few million more dollars investment. The scaling laws for pure electrostatic fusors aren't as beneficial as the model he's proposing, but I think that the math works for his model.
It also helps that he gave the hardware to Jim Benson, for obvious reasons to anyone who knows Jim and SpaceDev. Jim may not have enough money to pursue this super-actively, but Jim has a very strong clue, and knows how to talk business to people.
The APC InfraStruXure Express is a full-sized cargo truck trailer, bigger than a container. It's not as mobile as containers are. But it does include the A/C units (Sun's product needs chilled water input, apparently).
A large investment bank running a datacenter on "at best 100 megabit" ??? For data-intensive workloads? I don't know if you have a SAN behind that or not, but... you don't need a grid, you need a gig switch and an architect internally who has a clue and can bring management around.
I've been at two investment banks, one midsized and one gargantuan. Gargantuan one has a grid, along with piles of Linux servers, piles of Sun servers, large medium and small databases of both transactional and data warehousing nature and software choice. The grid has its place in things, but that place is not doing any of the actual trading. If someone is suggesting that a grid is the right solution for trading, based on my knowledge of how trading is done at places I've been at, the apps, and the description that was given... run, don't walk, away. You may have a custom parallelizable griddable trading app, but I've never seen one before. Trading apps typically are network, data, and CPU centric in a very internally connected way. Grids are pretty much the absolutely wrong solution for the trading apps I have seen. It might be able to run on one, but it's a complete architectural mismatch.
I don't know why this got modded insightful, it's entirely wrong. A turbine is a axial or centrifugal flow gas or liquid flow to mechanical energy converter. A gas turbine, as the article is about, is a heat engine with a compressor, combustor, and power take off turbine which at least powers the compressor, and for non-jet gas turbines also powers the mechanical power output. As a heat engine, the Carnot cycle is entirely appropriate.
I was the chief engineer of a CEV interested party and COTS bidder. The statement that "in the event of an abort, the re-entry loads would likely not be survivable" depends entirely on vehicle and vehicle heatshield design specifications, and abort scenario assumptions. Using parametric vehicle design assumptions as weak as early CEV assumptions, yes, you lose the vehicle and crew within a certain abort window when you're high but not moving fast enough sideways yet, and you end up with a rather brutal nonlifting reentry back into very dense atmosphere. Taking surviving that abort as a design requirement is a perfectly reasonable design constraint, and our COTS vehicle had lineage from that design requirement (for the Atlas-V, Delta-IV, and Falcon-0).
If the server starts to swap, you've lost the battle. But randomly killing things or locking up is losing the war.
It's fine to set off alerts and alarms if you're paging. You should set off alerts and alarms if your servers start paging. Randomly killing things instead? Insanity.
You can never build reliable services for users/customers unless you can handle random or accidental error conditions gracefully. Swap space is a cheap and easy key way to do that.
I still use a small multiplier, typically 2-3x physical RAM, for swap partition sizes on Solaris, Linux, xBSD, etc.
Systems typically are paging less now that we have multiple gigs of RAM per server, but if something goes wrong, the disk is so cheap that having the overhead installed and ready to use is fine. Having a live, active safety margin is just good sytem planner sense.
If you skimp on OS hard disks so much that 2-3x physical RAM is an excessive chunk out of the hard disks, then you're doing something wrong.
Nobody's positioning PATA/SATA FC drive units as "Low end" anymore. I don't have the detailed statistics, but these were just coming out in 2003, and now dominate the marketplace in terms of volume of drives sold into large enterprises.
The PATA ones make me a little nervous, but SATA (especially the ones with command tag queueing and such) is generally just fine.
Capricorn is the system build spinoff from the Internet Archive; a friend of mine who works there was doing some of the QA work on these units. He's pretty picky about flaky hardware, and these measured up fine.
The SpaceX "Dragon" capsule will launch on the Falcon 9 launcher, not the Falcon 1 which costs $6 million and change.
The Falcon 9 list price (see http://www.spacex.com/falcon_overview.php ) is $27 million for the basic 3.6 meter diameter fairing. For that price, you get around 9 tons (9,300 kg) lifted to low earth orbit, based on the announced specifications.
I am glad to see that they got one of the contracts. This is good for the industry. So is the Rocketplane Kistler thing, sort of, but there's already been $500 million spent on the Kistler vehicle and it's only half-built, so I have my worries about that one...
Your mileage may vary, they haven't built a Falcon 9 yet or successfully launched a Falcon 1 yet, etc.
Disclaimer: my company was a COTS phase 1 competitor, proposing to launch on a Falcon 9, which SpaceX was cheerfully interested in selling me despite their own Dragon project.
I'd like to second John's comments. He only has explored the trade space near realistic rocket fuels in depth; if you go outside it, there are whole categories of off the shelf, well known in the explosive industry explosive liquids.
TATP is about the dumbest possible route to a liquid explosive on a plane.
With any actual knowledge of explosives, any professional could come up with a few dozen easy options for alternate binary liquid explosives, or even pre-mixed liquid explosives which appear to be innocent sports drinks or sodas or wine or liquor, some of which could be safely drunk in moderate quantities to fool a security checkpoint guard into thinking it's a safe substance.
Several of these mixtures have no nitrogen whatsoever, and all of them have densities that don't alert the density-sensitive x-ray equipment.
Explosives experts have been quietly screaming at transportation security experts about this for years. Finally, once someone is caught trying it on a big scale, they listen.
Huh. I checked a couple of times to make sure it was persistent, across a couple of computers, but I guess it was anyways and expired. My apologies to the readers.
Control Number for the contract is: N043-226-0074
You can SBIR search for that control number at: DOD SBIR/STTR AWARDS - Custom Search
Strangely, regulation of homebuilt aircraft is less stringent than you might assume. The result is that homebuilt aircraft are more likely to have safety features (e.g. modern auto engines, ballistic parachute systems) than commercially built aircraft, because the commercial aircraft would have to undergo extensive safety testing to have these systems fitted. The result is that homebuilt aircraft have as good a safety record as commercially built designs.
Uh... neither the FAA nor EAA nor Kitplanes magazine nor any of the other reputable sources will back that up.
Homebuilts suffer more engine failures (even with 4-cylinder car engine conversions), more structural failures, etc.
That ballistic parachutes have lessened the fatality rate (and that's sure a good thing, and they should be added to all light planes) doesn't make them "safer". Just "less deadly".
Re:Easy - Think SAN - Apple XServe RAID + DNFStora
on
Best Server Storage Setup?
·
· Score: 2, Informative
Do not use XServe RAID. It's the worst possible pseudo-enterprise SAN product.
This is not to rag on Apple in general - the company is full of smart people, many of whom are friends. This is just a lame product in an otherwise excellent product line.
There are plenty of SATA based SAN storage devices out there which are cheap. I'm partial to Nexsan, having worked with them, and if you need slightly higher quality the Sun Storagetek, EMC/Dell boxes, etc.
Software RAID (Veritas or open source) striping on top of large HW RAID (RAID 5, or RAID 10) SAN storage array stacks works just fine.
A former coworker works there, so I'm biased, but the Mountain View Data PowerCockpit software seems to be pretty darn easy to use for large environments. Remote install, image-from-machine, install and configure many clones from an image, works with most of the PC OSes, etc.
Slashdot Mirror
And I quote:
If your rocket activity doesn't fall into that exception, then you need a FAA launch license or experimental launch permit, and all the associated paperwork and analysis.The United States has a land area of about 9.6 million square kilometers; California is about 0.4 million square kilometers. The US currently uses about 19%, or 1.8 million square kilometers of land, for agriculture.
... well ... innumerate. Especially if your fuel of choice is methanol, which can be produced from fermenting the leftover chaff from nearly all of the rest of the agricultural work nationwide, without dedicated land...
So what you're saying is that we can't possibly use 22% of our agricultural land to produce fuels. That is a claim which is
It would take about 2 million square km of cheap amorphous solar cell to give every man, woman, and child expected to be living worldwide at the population peak in 2060ish as much electrical power as people in the US use per capita now. We can treat this as a reasonable limit case for how much we need.
The earth has a surface area of around 510 million square km.
We'd preferentially want to use equatorial waters, which limit you to about 200 million square km, but that's still only using about 1% of the total ocean surface area.
Those solar cells tend to have a similar reflectance/absorbed as heat ratio as ocean water; that heat will end up slightly more preferentially in the air rather than in the water, but that's not a huge effect. Only about 10% of the total solar energy will come out in electricity and be "lost" compared to water's thermal absorbtion.
The total impact here is not negligible but is pretty minor. We shouldn't ignore climatic issues, but they are likely to be small, and in the opposite direction from global warming's impact.
Oh dear god, no. Yes, but noooooooo.......
And cross-training lets you solve larger problems. If all you can do is one job, you're a worker drone. If you understand several, you can solve cross-discipline problems.
Most college students who take in $1.3 million over 2 years are doing so via drug dealing. It doesn't take a post-9/11 conspiracy seeking banker to see something suspicious there.
Apparently this was the nearly unheard of exception, but that doesn't indicate that the suspicion was unreasonable.
Normal screws the size of nails tend to fail in shear at much lower stress. This is not bullshit.
Larger screws made out of stronger alloys don't, but are typically too big to usefully stick a 2x4 to another 2x4, or hold a sheet of plywood into a 2x4 with typical installation accuracy. And require a pre-drilled hole, which at least doubles the time to install. These screws are not useful for typical building construction tasks. Cracking the wood all to hell installing oversize nails or screws incorrectly is far from the best solution.
Wood is a hard material to join really well. You can do all sorts of half-ass methods and get two pieces of wood to stick together adequately, but doing a really good job is a lot harder. Because it's got grain and fiber, you need a lot of bearing surface to avoid the connector pulling out. Screws do great at that, but have less shear resistance, and lower cost screws are too brittle and crack right off in shear (and sometimes in tension). Nails are great at shear and are made out of alloys that rarely crack, but can pull right out. Boat nails, ring nails, other stuff is out there, but this seems to be a pretty big advance in balancing the shear and tension capabilities, ease of installation, etc.
For absolute optimal strength, pre-drilled carefully sized screws work pretty well. This nail should be about as strong, but about 10% the effort to install, and probably a tenth the cost for the fastener.
There was a time that it was safe to assume that people at least had built a treehouse or some such and had a clue about basic woodworking techniques. Apparently that time is now past.
...but for anything other than programmer teams, I want my people talking and cooperating on fixing problems, and cubes, open offices, bullpens and the like work just dandy.
I do IT operations and development rather than programming, so they are different work types. Joel may be right for cutting edge programmer productivity. But I've also seen very productive very loud programmer teams in open offices.
Some programmers will do terribly in that environment, but many will either thrive on the noise or tune it out (or put on headphones).
Niagra and Niagra 2 have lousy floating point performance (1 FPU for entire chip, shared by all the cores). Given that the DARPA project is for FLOPS, Nigra is just about the worst processor one could propose for the project.
I love the Niagra design; for 90% of what I need done, it does great. It's just terrible at floating point.
Sometime down the line, past Niagra 2, one could posit a version of such a chip with enough floating point units that it's efficient in FLOPS; it's an obvious upgrade of the current chips. However, that also is not optimal for FLOPS in the HPC regime. HPC is all about hiring enough computer scientists and physicists to micro-optimize the code so that you make close to theoretical maximum efficiency in utilizing the CPU cores. Niagra is all about keeping enough contexts on the chip that you can productively use the time that normal programs spend wasted, waiting for main memory accesses and so on. HPC by definition spends the CS time and effort to avoid that already.
Hey Derek. I take the flip side interpretation of this... the basic concept is just a http://en.wikipedia.org/wiki/Farnsworth-Hirsch_fus or Farnsworth Fusor, which is known to work (you can buy tabletop neutron generators in that configuration), with a couple of major variations, including the direct ion and electron well accellerators. The reason Farsnworth Fusors aren't practical for largescale power generation is that they more or less unavoidably lose energy to ion or electron collisions with the accellerator grid, which everyone has known for decades. It's also been widely postulated for decades that some form of magnetic isolation of the grids might enable you to get around that; there were arguments that the math worked and basic physics worked in the early 1980s, for example, but nobody had any idea how to do the detailed configuration to actually build a magnetically isolated grid fusor.
Bussard was openly talking about working on magnetic isolation in the 80s and 90s but hadn't really gotten far enough for anyone to believe that it was in fact necessarily possible. Then he shut up about it, and I think that the experts conclusion was that it either didn't work or his funding had run out. Assuming he's not lying in the talk (and I sort of doubt he'd do that), the actual story was that he was funded at a low rate with a nondisclosure restriction, and it took him 11 years to work on it enough to figure out the right combination of secret configuration and ingredients sauce to make the magnetic isolators actually work. The results he describes from his last set of tests, and the test configuration he described, sound exactly like what a successful working magnetic isolator would, as far as I can tell. His physics/engineering project has wandered over to where the theoretical predictions said things might work twenty years ago, and they seem to have worked. The fundamental question all along was whether the magnetic isolators were purely a mathematical construct, or if there was in fact a workable geometry which could make them real physical entities. The answer on first inspection is that yes, there must be, because it seems like they've demonstrated one.
Now that he's described it... I've looked into this myself in the past, considering building a conventional electrostatic Farnsworth Fusor just for fun, and it seems really credible. I think he's right that a demonstration unit at low power would answer the question conclusively, with only a few million more dollars investment. The scaling laws for pure electrostatic fusors aren't as beneficial as the model he's proposing, but I think that the math works for his model.
It also helps that he gave the hardware to Jim Benson, for obvious reasons to anyone who knows Jim and SpaceDev. Jim may not have enough money to pursue this super-actively, but Jim has a very strong clue, and knows how to talk business to people.
The APC InfraStruXure Express is a full-sized cargo truck trailer, bigger than a container. It's not as mobile as containers are. But it does include the A/C units (Sun's product needs chilled water input, apparently).
A large investment bank running a datacenter on "at best 100 megabit" ??? For data-intensive workloads? I don't know if you have a SAN behind that or not, but... you don't need a grid, you need a gig switch and an architect internally who has a clue and can bring management around.
I've been at two investment banks, one midsized and one gargantuan. Gargantuan one has a grid, along with piles of Linux servers, piles of Sun servers, large medium and small databases of both transactional and data warehousing nature and software choice. The grid has its place in things, but that place is not doing any of the actual trading. If someone is suggesting that a grid is the right solution for trading, based on my knowledge of how trading is done at places I've been at, the apps, and the description that was given... run, don't walk, away. You may have a custom parallelizable griddable trading app, but I've never seen one before. Trading apps typically are network, data, and CPU centric in a very internally connected way. Grids are pretty much the absolutely wrong solution for the trading apps I have seen. It might be able to run on one, but it's a complete architectural mismatch.
I don't know why this got modded insightful, it's entirely wrong. A turbine is a axial or centrifugal flow gas or liquid flow to mechanical energy converter. A gas turbine, as the article is about, is a heat engine with a compressor, combustor, and power take off turbine which at least powers the compressor, and for non-jet gas turbines also powers the mechanical power output. As a heat engine, the Carnot cycle is entirely appropriate.
I was the chief engineer of a CEV interested party and COTS bidder. The statement that "in the event of an abort, the re-entry loads would likely not be survivable" depends entirely on vehicle and vehicle heatshield design specifications, and abort scenario assumptions. Using parametric vehicle design assumptions as weak as early CEV assumptions, yes, you lose the vehicle and crew within a certain abort window when you're high but not moving fast enough sideways yet, and you end up with a rather brutal nonlifting reentry back into very dense atmosphere. Taking surviving that abort as a design requirement is a perfectly reasonable design constraint, and our COTS vehicle had lineage from that design requirement (for the Atlas-V, Delta-IV, and Falcon-0).
It's fine to set off alerts and alarms if you're paging. You should set off alerts and alarms if your servers start paging. Randomly killing things instead? Insanity.
You can never build reliable services for users/customers unless you can handle random or accidental error conditions gracefully. Swap space is a cheap and easy key way to do that.
I still use a small multiplier, typically 2-3x physical RAM, for swap partition sizes on Solaris, Linux, xBSD, etc.
Systems typically are paging less now that we have multiple gigs of RAM per server, but if something goes wrong, the disk is so cheap that having the overhead installed and ready to use is fine. Having a live, active safety margin is just good sytem planner sense.
If you skimp on OS hard disks so much that 2-3x physical RAM is an excessive chunk out of the hard disks, then you're doing something wrong.
Nobody's positioning PATA/SATA FC drive units as "Low end" anymore. I don't have the detailed statistics, but these were just coming out in 2003, and now dominate the marketplace in terms of volume of drives sold into large enterprises.
The PATA ones make me a little nervous, but SATA (especially the ones with command tag queueing and such) is generally just fine.
Capricorn is the system build spinoff from the Internet Archive; a friend of mine who works there was doing some of the QA work on these units. He's pretty picky about flaky hardware, and these measured up fine.
The SpaceX "Dragon" capsule will launch on the Falcon 9 launcher, not the Falcon 1 which costs $6 million and change.
The Falcon 9 list price (see http://www.spacex.com/falcon_overview.php ) is $27 million for the basic 3.6 meter diameter fairing. For that price, you get around 9 tons (9,300 kg) lifted to low earth orbit, based on the announced specifications.
I am glad to see that they got one of the contracts. This is good for the industry. So is the Rocketplane Kistler thing, sort of, but there's already been $500 million spent on the Kistler vehicle and it's only half-built, so I have my worries about that one...
Your mileage may vary, they haven't built a Falcon 9 yet or successfully launched a Falcon 1 yet, etc.
Disclaimer: my company was a COTS phase 1 competitor, proposing to launch on a Falcon 9, which SpaceX was cheerfully interested in selling me despite their own Dragon project.
I'd like to second John's comments. He only has explored the trade space near realistic rocket fuels in depth; if you go outside it, there are whole categories of off the shelf, well known in the explosive industry explosive liquids.
TATP is about the dumbest possible route to a liquid explosive on a plane.
With any actual knowledge of explosives, any professional could come up with a few dozen easy options for alternate binary liquid explosives, or even pre-mixed liquid explosives which appear to be innocent sports drinks or sodas or wine or liquor, some of which could be safely drunk in moderate quantities to fool a security checkpoint guard into thinking it's a safe substance.
Several of these mixtures have no nitrogen whatsoever, and all of them have densities that don't alert the density-sensitive x-ray equipment.
Explosives experts have been quietly screaming at transportation security experts about this for years. Finally, once someone is caught trying it on a big scale, they listen.
Huh. I checked a couple of times to make sure it was persistent, across a couple of computers, but I guess it was anyways and expired. My apologies to the readers. Control Number for the contract is: N043-226-0074 You can SBIR search for that control number at: DOD SBIR/STTR AWARDS - Custom Search
Do not use XServe RAID. It's the worst possible pseudo-enterprise SAN product. This is not to rag on Apple in general - the company is full of smart people, many of whom are friends. This is just a lame product in an otherwise excellent product line. There are plenty of SATA based SAN storage devices out there which are cheap. I'm partial to Nexsan, having worked with them, and if you need slightly higher quality the Sun Storagetek, EMC/Dell boxes, etc. Software RAID (Veritas or open source) striping on top of large HW RAID (RAID 5, or RAID 10) SAN storage array stacks works just fine.
A former coworker works there, so I'm biased, but the Mountain View Data PowerCockpit software seems to be pretty darn easy to use for large environments. Remote install, image-from-machine, install and configure many clones from an image, works with most of the PC OSes, etc.
- Master server / slave (media) server
- Central management point for the whole enterprise's backups (master server)
- User friendly restore management for end users
- Application-aware hot / warm backup plugins for enterprise apps like Oracle, SAP, Peoplesoft, Siebel, Informix, Sybase, Exchange
....
- Optional global management of multiple sites from a master master server
- Native clients for all OSes including Windows
- Tape vaulting management software addon
- Support for arbitrarily large tape libraries
- Block-level incremental backup option
Just off the top of my head.