Have you ever noticed that when you know a lot about an event or person you are associated with that gets written up in the news paper it is --without exception--grossly wrong? I mean positively without exception its always got factual errors or exaggerations or misstatements. So do you suppose that when you dont know anything about a subject and you read an article, its somehow correct?
As someone who has from time to time been the victim scientist in the company press release its awful. people assume you were bragging or dont know dick about your own work, because some reporter shaped your words. If you make a simple analogy to say base ball, you can bet your whole research program will become a giant metafor beginining with you hitting one out of the park.
its embarassing and gives people the wrong impression of you. plus every dorkl in the world then writes you an e-mail to say how you got something wrong.
The part I dread the most is that they often send you an advance copy to correct. And its always unsalvagable. you correct as much as you can but by construction you cant real change the gross distortions.
the comments so far to my post are interesting. So far two replys have said my estimates are too low and one says they are too high.
my estimates were based on a wild but rational guess that AOL spends between a hundred thousand and 10 million dollars per year in all costs fighting spam. by all costs I mean people setting up complaint websites, engineers to figure out how to recognize spam, etc.... Of course some costs are recoverable. like if I have to buy a bigger mailbox this costs AOL nada, infact it makes them money.
in any case if you accept these estimates as a rational range, and in fact if we just pick a number in this range: lets say 360,000$ per year. then the cost per spam at a billion per day is 0.000001 dollars per spam to AOL. If you think that's low then well multipy it by ten if you want.
there is a claim that spam costs money. Money to the ISP for bandwidth and money to the end user for reading/deleting. is this really true? well certainly I delete lots of spam and it costs me time. but what about the ISP?
I would guess that deleting spam is about as expensive as transmitting it for an ISP. that is the processor intensive task of scoring and removing a spam probably is a wash with the processor light task of tranmitting and storing it. Now for the sake of argument lets just guess a wild number for the cost of filtering or passing along a spam. lets say 0.001 dollars.
if that were true then a billion spam deleted would cost AOL 1million dollars per day (plus the ones that got through). that would be a third of a billion dollars a year. THat seems way to high. So it must be less. SO maybe its
0.000001 cents?? that would come to a third of a million dollars a year.
My guess is that the latter is probably a good guess. why? well how many engineers has AOL assigned to the de spamination? perhaps a third of a million dollars worth every year? it would of course not make sense to spend more on de spamination than the harm it costs.
so anyhow assuming this wild guessing is within an order of magnitude then the proper charge to fine a spammer would be some multiple of 0.000001 dollars per spam sent. which is not an awful lot.
so is spam really that costly to ISPs??? Maybe not
I love igor and have used it for 12 years now. It's matrix format is clumsy compared to R or Matlab. but for line plotting and data analysis I really like it. its script language is VERY fast (around half as fast as C) compared to say Matlab. The best part is that it is both GUI and command line so you have the best of both worlds. and its easy to come back to after you set it aside for a while (use the gui till you remember the commands). the on-line help is quite helpful too.
The next best thing is the ability to save and restore your entire state (plots, command history, variable and array contents, scripts, notes,... well everything) in a compact single file that is crossplatform with windows and macs.
finally it is very mac like in the way it works. I find this very nice. Other sci programs are good but dont act mac-like.
but my most favorite aspect is that this software is written by physicists and statistical quantum optics people. When you tell them what your are doing they sometimes actually get interested in it and will write you a special piece of code to do it.
the worst part of IGOR is that it is now so old, there are lots of options on every command rather than a consistent interface. So its becomeing a little less mac-like with time. this actually is fine for unix minded folks but confusing for many mac people. I hate reading man pages I like things that are intuitive.
coroporate sponsorship of media is the norm if you take a historical view. Indeed for all known history the arts have been almost exlusively supported by patrons not the masses. the wealthy, the kings, the lords, the church, and the state, have been the source of artisitic patronage beyond all written history. (think of the surviving art from the ancients: the mayan murals, the egyptian pyramids were the public art but it was not private). Micheal angelo painted for his patrons.
at only breif flickers in history has there been a middle class that could support the arts through small sales commerical routes. Troubadors may have made aa living but they were not stars, whose offerings were trades to others. Perhaps breifly in egypt there was a middle class. Perhaps briefly a few art centers, like venician glass makers held brief monopolies on desirabel art. but never for long.
it is only the rise of the ubquitous middle class, and a widespread media that has created the commerical conduits for art we have today. there is nothing to suggest these channels should or will be enduring. We as a generation or two grew up and thought these the norm but we were wrong.
To the extent that artistis are conduits of expression and the exchange of ideas, is this good or bad? its not clear. there are commmercial forces to tow the political norm on all artists whether they have patrons or must please the masses. Indeed one might claim that given the financial independence offerec by a patron is what frees the artist to challenge popular norms. You would not see many commercial artist these days advocating buttfucking small boys, but certainly many poets in greece spoke well of the idea. I know thats a bit gross, but I say it to make the point that stong ideas can come about when you dont have to please everyone.
After pondering this some I have come to the conclusion that this is a real threat. at first I dismissed it because it was going to take a bank employee with access to programming the machines low level inputs, plus a Very large list of card numbers, plus access to the pin offsets, plus a way to launder the money, plus the ability to make 15 tries without losing the card or having to override the system (which would get noticed).
but then I thought, well where could you do this an not get caught? how about North Korea or Nigeria. North Korea already mints high tech conterfeit US 100 dollar bills on government printing presses. So this would be small but useful potatoes.
but more important than the money, It also would make a nice weapon: UN provokes N. Korea, N korea dumps 100,000 cards with pins written on them in say the NY subway system. Next day all ATM banking is halted world wide. Nice little panic. Travelers stranded. Runs on banks as people have to now go inside to get money and they run out of cash. Anyhow you get the idea.
or maybe just one of the millions of merchant accounts visa hands out is owned by..... well you name it. Yikes
oops...posting with the correct formatting this time: The Register reports that Mike Bond and Piotr Zielinski have detailed how any ATM programmer (bank, repairman, etc..) insider can crack any ATM PIN in just 15 guesses. Banks use a hardware encryption scheme to avoid the having a crackable psswd-like file. Oops...turns out theres a hole in the hardware design. Direct link to download the pdf paper.
Here is how the crack works.
first you have to understand how the pin is generated.
banks had two problems they needed to solve, first an ATM had to be able to verify a card even if it went off-line from the bank computers. Thus to allow for on the spot verification, the pin has to derivable from the card somehow. Second, they also did not want to endure the security risk having to distribute a list of all PIN numbers of all cards to all machines, even if it was encrypted.
So the scheme they came up with is they take your PIN number and DES encrypt it, and the first four digits of the encrypted number becomes your base PIN. Then to allow you to change your pin, they permit an offset number. Since knowing this offset number does not tell anyone the base PIN, these offset numbers can be kept in the public domain and distributed worldwide.
thus when you type in your "pin" number to an ATM the sequence of steps is the machine reads the account code off the mag stripe, DES encodes it, grabs the first four numbers, adds your public offset, and compares it to the number you typed in at the key pad.
to keep everything secure the entire process is done in hardware. So even a priviledged bank employee could not have access to the encrypted account code and thus learn the PIN.
But wait, there's just one teeny tiny extra step I omitted that causes all the problems. when you DES encode something you get back a HEX number and since PINS are decimal you have to convert it to a decimal number. There's lots of ways you could do this, but what is done is simply to have a table that maps the 15 hex digits 0...F many-to-one down to 0...9.
Again still no problem if this mapping had been done in hardware. Unfortunately, it was not viewed as a securtiy risk and this mapping table is not fixed but is rather a software input to the hardware unit. Any one with access to the hardware device such as a priviledged bank employee or a repair man, or someone who found one at a salvage yard can send a substitute table to the hardware. And thats where the problem lies.
The paper gives several crack approaches one of which takes 15 tries maximum and is not easily explianed in a few words. they also give a simpler approach that takes max of 46 steps to get the pin which I'll explain.
first change the many-to-one mapping to all zeros, except for 1 digit. say this digit is a 3. Then type in a trial PIN of 0000. the hardware unit will say this pin is a correct match unless the encrypted Account number happens to have a 3 anywhere in it. (all other get mapped to zero) Next Change the map to all zeros, except say for say the digit 4, and repeat. after trying all ten digits, you know know which digits are in the PIN number. Now you just try all permuations of these. worst case is a total of 36+10=46 trials.
Their other algorithm is more efficient (only 15 trials maxiumum), but you get the idea.
I note that this is a big problem for the banks. The reason is that it would not simply do to replace the hardware units with ones that have a fixed map table. The PINS are crackable by anyone who still has one of the old hardware units. To fix the system they would have to both change all of the ATM hardware, change the DES salt in the hardware (to render old machines useless), and change everyone's PINS. this would all have to be done simultaneouly, world wide in every ATM for the banking systems ATMs not to stop working for customers. alternatively I guess they could upgrade all the hardware slowly if they were willing to leave the crack in place until they finished. to do this they woul have to have two sets of offsets. one for the new machines and one for the old machines. the cards would remain crackable until the last machine was removed and the users changed their PIN numbers.
I note that in a real system it only takes about 5000 tries on average to crack a 4 digit pin. However, the hardware units limit the rate of trials, so that reducing the number of trials by a couple orders of magnitude is significant.
The Register reports that Mike Bond and Piotr Zielinski have detailed how any ATM programmer (bank, repairman, etc..) insider can crack any ATM PIN in just 15 guesses. Banks use a hardware encryption scheme to avoid the having a crackable psswd-like file. Oops...turns out theres a hole in the hardware design. Direct link to download the pdf paper.
Here is how the crack works.
first you have to understand how the pin is generated.
banks had two problems they needed to solve, first an ATM had to be able to verify a card even if it went off-line from the bank computers. Thus to allow for on the spot verification, the pin has to derivable from the card somehow. Second, they also did not want to endure the security risk having to distribute a list of all PIN numbers of all cards to all machines, even if it was encrypted.
So the scheme they came up with is they take your PIN number and DES encrypt it, and the first four digits of the encrypted number becomes your base PIN. Then to allow you to change your pin, they permit an offset number. Since knowing this offset number does not tell anyone the base PIN, these offset numbers can be kept in the public domain and distributed worldwide.
thus when you type in your "pin" number to an ATM the sequence of steps is the machine reads the account code off the mag stripe, DES encodes it, grabs the first four numbers, adds your public offset, and compares it to the number you typed in at the key pad.
to keep everything secure the entire process is done in hardware. So even a priviledged bank employee could not have access to the encrypted account code and thus learn the PIN.
But wait, there's just one teeny tiny extra step I omitted that causes all the problems. when you DES encode something you get back a HEX number and since PINS are decimal you have to convert it to a decimal number. There's lots of ways you could do this, but what is done is simply to have a table that maps the 15 hex digits 0...F many-to-one down to 0...9.
Again still no problem if this mapping had been done in hardware. Unfortunately, it was not viewed as a securtiy risk and this mapping table is not fixed but is rather a software input to the hardware unit. Any one with access to the hardware device such as a priviledged bank employee or a repair man, or someone who found one at a salvage yard can send a substitute table to the hardware. And thats where the problem lies.
The paper gives several crack approaches one of which takes 15 tries maximum and is not easily explianed in a few words. they also give a simpler approach that takes max of 46 steps to get the pin which I'll explain.
first change the many-to-one mapping to all zeros, except for 1 digit. say this digit is a 3. Then type in a trial PIN of 0000. the hardware unit will say this pin is a correct match unless the encrypted Account number happens to have a 3 anywhere in it. (all other get mapped to zero) Next Change the map to all zeros, except say for say the digit 4, and repeat. after trying all ten digits, you know know which digits are in the PIN number. Now you just try all permuations of these. worst case is a total of 36+10=46 trials.
Their other algorithm is more efficient (only 15 trials maxiumum), but you get the idea.
I note that this is a big problem for the banks. The reason is that it would not simply do to replace the hardware units with ones that have a fixed map table. The PINS are crackable by anyone who still has one of the old hardware units. To fix the system they would have to both change all of the ATM hardware, change the DES salt in the hardware (to render old machines useless), and change everyone's PINS. this would all have to be done simultaneouly, world wide in every ATM for the banking systems ATMs not to stop working for customers. alternatively I guess they could upgrade all the hardware slowly if they were willing to leave the crack in place until they finished. to do this they woul have to have two sets of offsets. one for the new machines and one for the old machines. the cards would remain crackable until the last machine was removed and the users changed their PIN numbers.
I note that in a real system it only takes about 5000 tries on average to crack a 4 digit pin. However, the hardware units limit the rate of trials, so that reducing the number of trials by a couple orders of magnitude is significant.
Cathedrals and Nazi's use infrasound
on
Soundless Music?
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· Score: 4, Informative
This is not news and its bad science. Its been VERY well documented for over 1000 years that infrasound stirs emotions. Cathedrals have long had infrasonic and ultrasonic pipes in the organs. Nazi's used to play infrasonics at rallys to insight violent emotions.
dont beleive me? just do a google search for "cathedral infrasonic organ". Or check out this page which mentions the use by nazi's
the fact that the articel mentions none of this prior work sugests this is crap science.
If am interpreting this correctly, then this is saying that apples will communicate with extreme cards at the full data rate and the b-cards at the lower data rate. as you add more b-cards naturally the throughtput of the system goes down.
this makes perfect sense from a bandwidth slice point of view. if each card is getting an equal fraction of bandwidth (or time or whatever) and the b- cards are only exploiting that bandwidth at their normal 11MB/s flux then well yes they are wasting bandwith (but thats becasue they are B-cards).
the transmitter is still jamming bits as fast as it can, it just cat jam them as fast to the B-cards
of course a better situation would be if the bandwidth could be shared better so the b-cards got a smaller slice. but I doubt the b-cards would work that way.
The reason the heavy water plants were in norway and not back in the reich-land was they were co-located near easy access to electric power--hydro power. this was needed to product the heavy water.
Bombing a dam is damn hard. seen from the air they are very small targets. And they are concrete and over built. even if you hit the top you have not done much damage. to destroy the dam you have to hit is near the bottom where the water pressure is high. hence the need for a raid on the ground: to hard to hit.
Enter the skip bomb. the Skip bomb is a spinning cyllindric bomb dropped in the water above the dam. it skips, skips, skips and slams in to wall of the dam. but it does not explode. instead the back spin makes it claw its way down the side the dam where it detonates near the bottom.
I've brushed up against reconfigurable computing engineers in various applications I've had over the years. The last one was for trying to process laser radar returns coming in at gigabits per minute so we could do real time 3-D chemical spectoscopy of the atmosphere at long range. The problem with conventional hardware was the busses were too slow and the data rate too fast too cache, and too much to archive on disk. you could not effieicently break the task into multiple CPU since just transfering the information from one memory system to the next would become the bottleneck, breaking the system.
FPGAs worked pretty well here because they could handle the fire hose data rate from front to back. Their final output was a small nuumber of processed bytes so that could then go to a normal computer for display and storage.
the problems the engnieers had was two fold. first in the early chips there were barely enough gates to do the job. and in the later ones form xylinx there were plenty of transistors but they were really hard to design properly. the systems got into race conditions were you had to use software to figure out the dynamic proerties fo the chip to see if two signals would arrive at the next gate in time to produce a stable response. you had to worry where on the chip two signals were coming from. it was ugly and either you accepted instability or failed prootypes or you put in extra gates to handle synchronization--which slowed the system down, and caused you to waste precious gates.
still my impression at the time was WOW. here is something that is going to work, its just a matter of getting better hardware compilers. Since then Los Alamos has written a C compiler that compiles C to hardware and takes into account all these details it used to take a team of highly experienced engineers/artists to solve.
Also someone leaked a project going on at National Instruments that really lit up my interest in this. I don't know what ever became of it, maybe nothing. but the idea was this. National instruments makes a product called "labview" which is a graphics based programming language whose architechute is based on "data flows" rather than procedural programming. in data flows, objects emitt and receive data asynchronously. when an object detects that all of its inputs are valid data it fires, does its computation (which might be procedural in itself, or it might be a hierarchy of data flow subroutines hidden inside the black box of the object) and emitts its results as they become valid. there are no "variables" per se just wires that distriuted emitted data flows to other waiting objects. the nice thing about this language is that its wonderful for instumentation and data collection, since you dont alwayd know when data will become available or in what order it will arrive from different sensors. Also there is no such thing as a syntax error, since its all graphical wiringing, no typiing, thus it is very safe for industrial control of dangerous instruments.
anyhow the idea was that each of these "objects" could be dynamically blown onto an FPGA. each would be a small enough computation that it would not have design complications like race conditions and all the objects would be self timed with asyncronous data flows.
THe current state of the art seems to be that no one is widely using the C-code or the Flow control languages. instead they are still using these hideous dynamical modelling, languages that dont meet the needs of programmers because they require to much knowledge of the hardware. I dont know why. maybe they are just too new.
However these things are not a panacea. For example, recently I went to the FPGA engineers here with a problem in molecular modeling of proteins. I wanted to see if they could put my fortran program onto an fpga chip. the could not, because 1) there was too much stored data required and 2) there was not enough room for the whole algorithm. So I thought well maybe they could put some of the slow steps on to the fpga chip. for example, given a list of 1000 atom coordinates, return all 1 million pair wise distances. This too proved incompatible for a different reason. When these fpga chips are connected to a computer system the bottleneck of getting data into and out of them is generally worse than that of a cpu (most commerical units are on PCMCIA slots or the PCI bus). thus the proposed calculation would be much faster on a ordinary microporcessor since most of the time is spent on reads and writes to memory.! there was however one way they could do it faster and that was to pipeline the calculations say 100 or 1000 fold deep. so that you ask for the answer for one array, and then go pick up the answer to the array you asked about 1000 arrays ago. this would have complicated my program too much to be useful.
these new FPGAs are thus exciting because they are getting so large and have so much onboard storage and fast internal busses that a lot of the problems I just mentioned may vanish.
My knowlege of this is about year out of date so I apologize if some of the things I said are not quite state of the art. But I suspect it reflects the commerially avialable world
As an apple stock owner I get the annual report. This fact has been in the annual report of many years now. IN deed recently they asked us to vote on ways to increace excectuive compensation. this is not newsworthy. I mean even if he did get 0$ compensation he'd still be willing to run the ocmpany since he has stock and stock options.
the 1$ is just the standard minimum for a contract. do you suppose he gets health benefits worth more than $1 too. i'd say so.
the thing with steve is that he loves running apple and it shows. that's why I did not worry about voting stock options for him. I did not have the sense he was going to pull an enron, goose the stock price and bail. On the other hand I was a bit nervous about the rest of the board. What made me less owrried was that some of the principles ate the time was larry ellison and the head of genetech. These people are also into their own bussinesses in the same way steve is into his. So i felt reassured.
maybe i'm wrong basing investment decisions on personality, but its the only stock I own I have not lost money on in the past several years.
But the tone of this post, that the $1 salary is a hypocritical lie just does not past the reality test. only a naive dupe would think that was his only compensation.
Okay here's a practical question some here can answer.
what is the practical range of a wifi card? I'm talking here about with real houses and stuff. mine does not seem to reach the room on the far side of the house. (I have concrete interior walls.) So I know it wont reach my neighbor on the far side of that room.
on top of this my 2.4Ghz phone does an excellent job of jamming the connection. I suspect the microwave deteriorates the signal too. Thus I have real worries about if networks based on wifi are practical at the micro-isp level.
Another question is if a wifi pcmcia card, and a typical link-sys or airport basestation unit have the same range. That is to say if I run software basestation on my mac does this have the same range and throughput as a real basestation?
The article divides up usage patterns of the back button in to modalities. the main one being jumping back to the portal entry page after burrowing down a thread. this is exactly what the SAFARI snapback does.
in my own defense this is not a thread about creationism, its about adaption. So I spent very few words on it. I was just trying to make an observation about a link between the two, not a full argument. Creationist tend to look at evolution statically and want to say see this critter is optimal but theres no way it could have reached this perfect state incrementally. I wanted to remark, that evolution is a dynamics process and its not about being optimal, its about who survives, and adatation is one survivial strategy.
but since you brought it up let me address one small point in your comment.
Thus there still isn't any known adaptive mechanism to get to DNA/RNA.
While of course we cant say "whence dna" there are a lot of good leads at the moment. The most promising in my opinion is the growing realization is that RNA can do both the functions of DNA and Proteins. That is it is an information storage system that can replicate itself and edit itself, and it can form chemically active self-folded structures just like proteins. In fact in a perfectly benign environment its not absurd to suggest that life could be composed entirely out of RNA and small naturally available molecules.
The reason life could not currently be composed out of RNA is that its a hostile world and a lot of the precursur molecules dont exist anymore (other animals used them up). RNA is chemically unstable and easily digested. plus its reaction rates are too slow making it a lousy catylist for many activities. On the other hand in a primordial world, without hostile agents, and no competiton one has all the time in the world to wait for a slow catylist. Its the poker hand again: a pair of twos wins if everyone has has dick. thus its not unthinkable that RNA is the missing link. the fact that RNS still is the middle man speaks volumes. But we will probably never really know unless we find some alternate biospace that evolved differently (the possible discovery of nanobes in deep mines and maybe asteroids comes to mind).
Now the sentence in my discourse you keyed on ("The answer is that being adaptive can beat being the best."
) could obviously be made into a book length discussion. I probably could have chosen my words more carefully too. perhaps I should have said "being adaptive can beat being the most optimally adapted organism to a current environment". For example, if every one lives on mice then the one with the perfect irreducibly complex mouse trap may be the dominant species, but a crappy one that also floats or catches fish on out of every thousand tries might be a more adaptive but marginal species in the present environment (e.g. imagine a speer planted in the ground that requires the mouse or fish to fall on it. Not exactly irreducibly complex, but definitely adaptive. one does not need the perfect mouse trap to get started if a shift (e.g. waterworld) in environment suddenly gives you an advantage.). There are others who have actually taken behe mouse trap argument literally and shown one can infact reduce it.
Or to put it another way, people with a family history of being prone to genetic mutation, or behavioural disorders, may in the long long long term have a greater influence on the genetics and sociology of future humanity, than those beautiful, well behaved people.
What I cant decide is if this slash dot community represents a breeding place for diversification under harsh conditions or is a swarm fuzzy well balanced world for a particularly obnoxious phenotype and is thus not promoting its own evolution.
this reminded me of an older paper that tried to rationalize why optimal growing conditions does not seem to favor rapid evolution of a species. That is what scant evidence there is, it appears that evolutionary diversity and advancement occurs under not the optimal growing conditions but rather in the harshest. e.g. at the highest altitude, hottest temperaures or any place life struggles to survive.
While its obvious that harsh conditions by themselves impose evolutionary pressure this does NOT promote diversity--after all that pressure only is placed on genes that govern adaptation to the environment, and even there there is generally a narrowing of the gene pool not an expansion.
No instead the diversity arises because you have left your old balanced environment and predators, and thus have LOST the finely honed evolutionary pressure on those genes. thus you can evolve semi randomly with little selective pressure, leading to diversity. Another factor leading not to diversity but to rapid differentiation is that when these new traits that have nothing to do with survival get chromosomally linked to the features that enhance a species survival in the harsh environment, they get amplified.
some people call this the poker hand effect. You dont need a royal straight flush to win. all you have to do is beat your opponents. Or to put it another way if you are trying to live in a chemical wasteplant out flow, you dont have to generate a a very good enzyme for digesting plastics, anything that is better than your competitors is good enough for now. You can evolve it more later.
this explanation is perhaps the simplest and best answer to creationists who want to insist that life is too complex a process to spring into existance fully developed (.e.g. behe's mouse trap argument). The answer is that being adaptive can beat being the best.
anyhow its interesting that a species poised to exploit an opportunity will evolve faster than one that dominates its native environment.
Twirlip, how do we deal with the case insensitivity in UFS. it occasionally happens that a linux package will contain a directory with two files like "HEAD" and head or ReadME and readMe of "configure" and CONFIGURE.
if you unpack this on an HFS+ system the files will overwrite each other. How does one escape this in HFS+? it should of course not happen on an all mac network but the xserve is intended to be nfs and smb connected to widows and linux machines who will no know they are on HFS+. Has apple installed some magic fix in the HFS+ system. I asked an apple tech and they said no this was still a problem and suggested UFS.
Woohoo. I have to eat my own words posted above. I just finished looking over the detailed specs in the apples pdf file and it turns out that the new RAID box has raid 5. this is great news. I wonder if they will retrofit the old 1-U xesrves to raid 5? or is the a feature of the new hardware raid controller?
any how I was mistaken--the apple web page did not mention the raid 5 so I assumed it was just the same as the old 1-U xserve. sorrty for the misinfomation
two words: raid 5. its missing from apple. You can buy a third party raid 5 however.
A while ago I bought two xserves to act as diskserves to a linux cluster and to backup my desktop macs. I bought these machines because I felt they were a good deal. I got bids on several pc based linux disk servers, as well as several NAS boxes. I was comparing 480GB machines. a high quality generic brand (supermicro) with scsi disks and dual Gigabit ran about $8000 (at the time). The lowest bid I got was $5000 but the unknown quality and reputation of the vendor was not satisfactory. The mac xserves ran just under $7000 using IDE disks with 4 indepenedent masters (out performs the scsi). Additionally the mac had other nice features such as: 1U versus 3U. hot swap. advanced admin tools.
I bought both the apple and supermicro based systems in the end and can compare them directly. . after I unpacked the mac I was even more impressed with the high quality construction and ease of access to the interior in comparison.
first the good news:
What really made it for me on the macs was the fact that I had to hire a sysadmin to correctly set up my linux box with load balancing, Ldap, mail server, and moreover to keep it patched and to monitor it. On the macs I set them up myself. No detected problems with load balance. and the mac tools let you set up nearly all the services you might want with an intuitive gui.
Actually, I had a few snags but even here I have to give apple a good reprot card. they chancged how they did network admin right when I got my box. so all the documentation was for the obsolete tools and none for the new. So I got things really screwed up with services I could not turne off once turned on. The machines would gag when they could not find their ldap serviers or when they were cut off from the internet. But I called apple on the free service plan. after a ten minute wait on came a guy who really knew his stuff and spent about an hour with me getting all of my various problems sorted out and teaching me the new system. And in fact the next day he called me back! said he had another idea about a question i had asked him. I was really impressed on the customer service. its much better than for my other mac computers. Since then Ive had mac people call me back three times with ideas for me. Now that the new tools are better docuimented (still a few gaps), life is easy.
perhaps the best feature is the software update feature. I get patches and new tools delivered automatically and have the confiudence they wont screw up my all apple configuration. thus I still have not needed a sys admin. At the purchase time I had considered some NAS boxes (e.g. iomega,snap...) for the purpose of making sys admin simple. But these things have lousy throughput for the price and aren't versatile computing machines.
Now the bad news:
However I have had three problems with my xesrves that I dont have with my linux box.
first no raid 5. that's absouluetly maddening. I bought a raid 5 solution from a third party but I'm nervous it wont be effieicnt or it will die someday when I do a self-update that makes it incompatible.
second, and this compounds the above problem is the UFS/HFS+ dichotomy. while macs do run UFS, they dont do it effieicently or with any advanced features like journalling. Moreover the OS and some mac apps wont work unless they are on UFS. so you always have to have a HFS+ partition. but wait! you cant partition a raid disk with different file systems (on apple) so this means if you want to have any hfs raid the whole disk has to be HFS+. on our four disk Xserve this means I ended up with two disks RAID1 HFS+ and and two disks UFS raid 1- a whopping 120GB of UFS out of my 480GB (raw) can be UFS. yuck!. fortunately there is now a partionalble raid 5 soultion from a theird party which fixes this issue. (the reason I wanted UFS, was because even though I lost some effieiceny i wanted no surprises for my linux systems due to the filenaming case sensitivity)
The third problem I have had is that while the admin tools are wonderful and run on remote machines, there are a few tools and apps that will not run remotely. for example, if I want to use the GUI software update remotely, I cant. I have to use the terminal CLI tool. This is not too bad, but its just an example. if you use other gui tools, like brickhouse firewall or whatever, you have to go to the terminal attactched to the machine.
My work around for this is to use OSXVNC which does the job. However there is a catch I dont like. You cant use osxvnc on a headless mac. that is you have to have a display device connected to the mac to use osxvnc!! there's no way I want to have a display for each mac xserve. Of course I could use a KVM switch but my preference would be that it should be unneccessary for remote admin. my work around here is that I can fool the macs by briefly connecting a display to them after boot. I can then unplug the display and OSXVNC will still work on my headless mac.
My conclusion is that apple has a wonderfulhigh quality machine. And it will work perfectly for you if you dont require UFS or remote admin of GUI based apps. When I bought my system I had just had a bad experience with 20 athalon servers that had died from heat delamination of the fans and were unstable due to current glithces from the cd roms. I was thus very risk averse. when I bought the apples I knew I was buying peace of mind, and not paying extra for it. I had no idea what good customer service I was going to get. PLus I did not realize I could also buy a complete replacement part kit (down to the motherboard) to have locally. Since my experience with their customer service I bought the extened warantee. its lot cheaper than a sys admin.
when mac comes out with native raid5 and someone writes a VNC that can run headless all will be well.
p.s. I apologize to the few slashdotters who are outraged when a post is reposted. this review was posted as a sub comment to a sub topic on an earlier artilce today. rightfully it belonged in this thread so I reposted it here.
two words: raid 5. its missing from apple. You can buy a third part raid 5 however.
A while ago I bought two xserves to act as diskserves to a linux cluster and to backup my desktop macs. I bought these machines because I felt they were a good deal. I got bids on several pc based linux disk servers, as well as several NAS boxes. I was comparing 480GB machines. a high quality generic brand (supermicro) with scsi disks and dual Gigabit ran about 8000 (at the time). The mac xserves ran just under $7000 using IDE disks with 4 indepenedent masters (out performs the scsi). Additionally the mac had other nice features such as: 1U versus 3U. hot swap. I bought both systems in the end. after I unpacked the mac I was even more impressed with the high quality construction and ease of access to the interior.
What really made it for me on the macs was the fact that I had to hire a sysadmin to correctly set up my linux box with load balancing, Ldap, mail server, and moreover to keep it patched and to monitor it. On the macs I set them up myself. No detected problems with load balance. and the mac tools let you set up nearly all the services you might want with an intuitive gui.
Actually, I had a few snags but even here I have to give apple a good reprot card. they chancged how they did network admin right when I got my box. so all the documentation was for the obsolete tools and none for the new. So I got things really screwed up with services I could not turne off once turned on. The machines would gag when they could not find their ldap serviers or when they were cut off from the internet. But I called apple on the free service plan. after a ten minute wait on came a guy who really knew his stuff and spent about an hour with me getting all of my various problems sorted out and teaching me the new system. And in fact the next day he called me back! said he had another idea about a question i had asked him. I was really impressed on the customer service. its much better than for my other mac computers. Since then Ive had mac people call me back three times with ideas for me. Now that the new tools are better docuimented (still a few gaps), life is easy.
perhaps the best feature is the software update feature. I get patches and new tools delivered automatically and have the confiudence they wont screw up my all apple configuration. thus I still have not needed a sys admin. At the purchase time I had considered some NAS boxes (e.g. iomega,snap...) for the purpose of making sys admin simple. But these things have lousy throughput for the price and aren't versatile computing machines.
However I have had three problems with my xesrves that I dont have with my linux box.
first no raid 5. that's absouluetly maddening. I bought a raid 5 solution from a third party but I'm nervous it wont be effieicnt or it will die someday when I do a self-update that makes it incompatible.
second, and this compounds the above problem is the UFS/HFS+ dichotomy. while macs do run UFS, they dont do it effieicently or with any advanced features like journalling. Moreover the OS and some mac apps wont work unless they are on UFS. so you always have to have a HFS+ partition. but wait! you cant partition a raid disk with different file systems (on apple) so this means if you want to have any hfs raid the whole disk has to be HFS+. on our four disk Xserve this means I ended up with two disks RAID1 HFS+ and and two disks UFS raid 1- a whopping 120GB of UFS out of my 480GB (raw) can be UFS. yuck!. fortunately there is now a partionalble raid 5 soultion from a theird party which fixes this issue. (the reason I wanted UFS, was because even though I lost some effieiceny i wanted no surprises for my linux systems due to the filenaming case sensitivity)
The third problem I have had is that while the admin tools are wonderful and run on remote machines, there are a few tools and apps that will not run remotely. for example, if I want to use the GUI software update remotely, I cant. I have to use the terminal CLI tool. This is not too bad, but its just an example. if you use other gui tools, like brickhouse firewall or whatever, you have to go to the terminal attactched to the machine.
My work around for this is to use OSXVNC which does the job. However there is a catch I dont like. You cant use osxvnc on a headless mac. that is you have to have a display device connected to the mac to use osxvnc!! there's no way I want to have a display for each mac xserve. Of course I could use a KVM switch but my preference would be that it should be unneccessary for remote admin. my work around here is that I can fool the macs by briefly connecting a display to them after boot. I can then unplug the display and OSXVNC will still work on my headless mac.
My conclusion is that apple has a wonderfulhigh quality machine. And it will work perfectly for you if you dont require UFS or remote admin of GUI based apps. When I bought my system I had just had a bad experience with 20 athalon servers that had died from heat delamination of the fans and were unstable due to current glithces from the cd roms. I was thus very risk averse. when I bought the apples I knew I was buying peace of mind, and not paying extra for it. I had no idea what good customer service I was going to get. PLus I did not realize I could also buy a complete replacement part kit (down to the motherboard) to have locally. Since my experience with their customer service I bought the extened warantee. its lot cheaper than a sys admin.
when mac comes out with native raid5 and someone writes a VNC that can run headless all will be well
Slashdot Mirror
As someone who has from time to time been the victim scientist in the company press release its awful. people assume you were bragging or dont know dick about your own work, because some reporter shaped your words. If you make a simple analogy to say base ball, you can bet your whole research program will become a giant metafor beginining with you hitting one out of the park.
its embarassing and gives people the wrong impression of you. plus every dorkl in the world then writes you an e-mail to say how you got something wrong.
The part I dread the most is that they often send you an advance copy to correct. And its always unsalvagable. you correct as much as you can but by construction you cant real change the gross distortions.
my estimates were based on a wild but rational guess that AOL spends between a hundred thousand and 10 million dollars per year in all costs fighting spam. by all costs I mean people setting up complaint websites, engineers to figure out how to recognize spam, etc.... Of course some costs are recoverable. like if I have to buy a bigger mailbox this costs AOL nada, infact it makes them money.
in any case if you accept these estimates as a rational range, and in fact if we just pick a number in this range: lets say 360,000$ per year. then the cost per spam at a billion per day is 0.000001 dollars per spam to AOL. If you think that's low then well multipy it by ten if you want.
is that cheap or expensive?
I would guess that deleting spam is about as expensive as transmitting it for an ISP. that is the processor intensive task of scoring and removing a spam probably is a wash with the processor light task of tranmitting and storing it. Now for the sake of argument lets just guess a wild number for the cost of filtering or passing along a spam. lets say 0.001 dollars.
if that were true then a billion spam deleted would cost AOL 1million dollars per day (plus the ones that got through). that would be a third of a billion dollars a year. THat seems way to high. So it must be less. SO maybe its 0.000001 cents?? that would come to a third of a million dollars a year.
My guess is that the latter is probably a good guess. why? well how many engineers has AOL assigned to the de spamination? perhaps a third of a million dollars worth every year? it would of course not make sense to spend more on de spamination than the harm it costs.
so anyhow assuming this wild guessing is within an order of magnitude then the proper charge to fine a spammer would be some multiple of 0.000001 dollars per spam sent. which is not an awful lot.
so is spam really that costly to ISPs??? Maybe not
The next best thing is the ability to save and restore your entire state (plots, command history, variable and array contents, scripts, notes,... well everything) in a compact single file that is crossplatform with windows and macs. finally it is very mac like in the way it works. I find this very nice. Other sci programs are good but dont act mac-like.
but my most favorite aspect is that this software is written by physicists and statistical quantum optics people. When you tell them what your are doing they sometimes actually get interested in it and will write you a special piece of code to do it.
the worst part of IGOR is that it is now so old, there are lots of options on every command rather than a consistent interface. So its becomeing a little less mac-like with time. this actually is fine for unix minded folks but confusing for many mac people. I hate reading man pages I like things that are intuitive.
at only breif flickers in history has there been a middle class that could support the arts through small sales commerical routes. Troubadors may have made aa living but they were not stars, whose offerings were trades to others. Perhaps breifly in egypt there was a middle class. Perhaps briefly a few art centers, like venician glass makers held brief monopolies on desirabel art. but never for long.
it is only the rise of the ubquitous middle class, and a widespread media that has created the commerical conduits for art we have today. there is nothing to suggest these channels should or will be enduring. We as a generation or two grew up and thought these the norm but we were wrong.
To the extent that artistis are conduits of expression and the exchange of ideas, is this good or bad? its not clear. there are commmercial forces to tow the political norm on all artists whether they have patrons or must please the masses. Indeed one might claim that given the financial independence offerec by a patron is what frees the artist to challenge popular norms. You would not see many commercial artist these days advocating buttfucking small boys, but certainly many poets in greece spoke well of the idea. I know thats a bit gross, but I say it to make the point that stong ideas can come about when you dont have to please everyone.
but then I thought, well where could you do this an not get caught? how about North Korea or Nigeria. North Korea already mints high tech conterfeit US 100 dollar bills on government printing presses. So this would be small but useful potatoes.
but more important than the money, It also would make a nice weapon: UN provokes N. Korea, N korea dumps 100,000 cards with pins written on them in say the NY subway system. Next day all ATM banking is halted world wide. Nice little panic. Travelers stranded. Runs on banks as people have to now go inside to get money and they run out of cash. Anyhow you get the idea.
or maybe just one of the millions of merchant accounts visa hands out is owned by
Yikes
oops...posting with the correct formatting this time:
The Register reports that Mike Bond and Piotr Zielinski have detailed how any ATM programmer (bank, repairman, etc..) insider can crack any ATM PIN in just 15 guesses. Banks use a hardware encryption scheme to avoid the having a crackable psswd-like file. Oops...turns out theres a hole in the hardware design. Direct link to download the pdf paper.
Here is how the crack works.
first you have to understand how the pin is generated.
banks had two problems they needed to solve, first an ATM had to be able to verify a card even if it went off-line from the bank computers. Thus to allow for on the spot verification, the pin has to derivable from the card somehow. Second, they also did not want to endure the security risk having to distribute a list of all PIN numbers of all cards to all machines, even if it was encrypted.
So the scheme they came up with is they take your PIN number and DES encrypt it, and the first four digits of the encrypted number becomes your base PIN. Then to allow you to change your pin, they permit an offset number. Since knowing this offset number does not tell anyone the base PIN, these offset numbers can be kept in the public domain and distributed worldwide.
thus when you type in your "pin" number to an ATM the sequence of steps is the machine reads the account code off the mag stripe, DES encodes it, grabs the first four numbers, adds your public offset, and compares it to the number you typed in at the key pad.
to keep everything secure the entire process is done in hardware. So even a priviledged bank employee could not have access to the encrypted account code and thus learn the PIN.
But wait, there's just one teeny tiny extra step I omitted that causes all the problems. when you DES encode something you get back a HEX number and since PINS are decimal you have to convert it to a decimal number. There's lots of ways you could do this, but what is done is simply to have a table that maps the 15 hex digits 0...F many-to-one down to 0...9.
Again still no problem if this mapping had been done in hardware. Unfortunately, it was not viewed as a securtiy risk and this mapping table is not fixed but is rather a software input to the hardware unit. Any one with access to the hardware device such as a priviledged bank employee or a repair man, or someone who found one at a salvage yard can send a substitute table to the hardware. And thats where the problem lies.
The paper gives several crack approaches one of which takes 15 tries maximum and is not easily explianed in a few words. they also give a simpler approach that takes max of 46 steps to get the pin which I'll explain.
first change the many-to-one mapping to all zeros, except for 1 digit. say this digit is a 3. Then type in a trial PIN of 0000. the hardware unit will say this pin is a correct match unless the encrypted Account number happens to have a 3 anywhere in it. (all other get mapped to zero) Next Change the map to all zeros, except say for say the digit 4, and repeat. after trying all ten digits, you know know which digits are in the PIN number. Now you just try all permuations of these. worst case is a total of 36+10=46 trials.
Their other algorithm is more efficient (only 15 trials maxiumum), but you get the idea.
I note that this is a big problem for the banks. The reason is that it would not simply do to replace the hardware units with ones that have a fixed map table. The PINS are crackable by anyone who still has one of the old hardware units. To fix the system they would have to both change all of the ATM hardware, change the DES salt in the hardware (to render old machines useless), and change everyone's PINS. this would all have to be done simultaneouly, world wide in every ATM for the banking systems ATMs not to stop working for customers. alternatively I guess they could upgrade all the hardware slowly if they were willing to leave the crack in place until they finished. to do this they woul have to have two sets of offsets. one for the new machines and one for the old machines. the cards would remain crackable until the last machine was removed and the users changed their PIN numbers.
I note that in a real system it only takes about 5000 tries on average to crack a 4 digit pin. However, the hardware units limit the rate of trials, so that reducing the number of trials by a couple orders of magnitude is significant.
The Register reports that Mike Bond and Piotr Zielinski have detailed how any ATM programmer (bank, repairman, etc..) insider can crack any ATM PIN in just 15 guesses. Banks use a hardware encryption scheme to avoid the having a crackable psswd-like file. Oops...turns out theres a hole in the hardware design. Direct link to download the pdf paper. Here is how the crack works. first you have to understand how the pin is generated. banks had two problems they needed to solve, first an ATM had to be able to verify a card even if it went off-line from the bank computers. Thus to allow for on the spot verification, the pin has to derivable from the card somehow. Second, they also did not want to endure the security risk having to distribute a list of all PIN numbers of all cards to all machines, even if it was encrypted. So the scheme they came up with is they take your PIN number and DES encrypt it, and the first four digits of the encrypted number becomes your base PIN. Then to allow you to change your pin, they permit an offset number. Since knowing this offset number does not tell anyone the base PIN, these offset numbers can be kept in the public domain and distributed worldwide. thus when you type in your "pin" number to an ATM the sequence of steps is the machine reads the account code off the mag stripe, DES encodes it, grabs the first four numbers, adds your public offset, and compares it to the number you typed in at the key pad. to keep everything secure the entire process is done in hardware. So even a priviledged bank employee could not have access to the encrypted account code and thus learn the PIN. But wait, there's just one teeny tiny extra step I omitted that causes all the problems. when you DES encode something you get back a HEX number and since PINS are decimal you have to convert it to a decimal number. There's lots of ways you could do this, but what is done is simply to have a table that maps the 15 hex digits 0...F many-to-one down to 0...9. Again still no problem if this mapping had been done in hardware. Unfortunately, it was not viewed as a securtiy risk and this mapping table is not fixed but is rather a software input to the hardware unit. Any one with access to the hardware device such as a priviledged bank employee or a repair man, or someone who found one at a salvage yard can send a substitute table to the hardware. And thats where the problem lies. The paper gives several crack approaches one of which takes 15 tries maximum and is not easily explianed in a few words. they also give a simpler approach that takes max of 46 steps to get the pin which I'll explain. first change the many-to-one mapping to all zeros, except for 1 digit. say this digit is a 3. Then type in a trial PIN of 0000. the hardware unit will say this pin is a correct match unless the encrypted Account number happens to have a 3 anywhere in it. (all other get mapped to zero) Next Change the map to all zeros, except say for say the digit 4, and repeat. after trying all ten digits, you know know which digits are in the PIN number. Now you just try all permuations of these. worst case is a total of 36+10=46 trials. Their other algorithm is more efficient (only 15 trials maxiumum), but you get the idea. I note that this is a big problem for the banks. The reason is that it would not simply do to replace the hardware units with ones that have a fixed map table. The PINS are crackable by anyone who still has one of the old hardware units. To fix the system they would have to both change all of the ATM hardware, change the DES salt in the hardware (to render old machines useless), and change everyone's PINS. this would all have to be done simultaneouly, world wide in every ATM for the banking systems ATMs not to stop working for customers. alternatively I guess they could upgrade all the hardware slowly if they were willing to leave the crack in place until they finished. to do this they woul have to have two sets of offsets. one for the new machines and one for the old machines. the cards would remain crackable until the last machine was removed and the users changed their PIN numbers. I note that in a real system it only takes about 5000 tries on average to crack a 4 digit pin. However, the hardware units limit the rate of trials, so that reducing the number of trials by a couple orders of magnitude is significant.
dont beleive me? just do a google search for "cathedral infrasonic organ". Or check out this page which mentions the use by nazi's
the fact that the articel mentions none of this prior work sugests this is crap science.
this makes perfect sense from a bandwidth slice point of view. if each card is getting an equal fraction of bandwidth (or time or whatever) and the b- cards are only exploiting that bandwidth at their normal 11MB/s flux then well yes they are wasting bandwith (but thats becasue they are B-cards).
the transmitter is still jamming bits as fast as it can, it just cat jam them as fast to the B-cards
of course a better situation would be if the bandwidth could be shared better so the b-cards got a smaller slice. but I doubt the b-cards would work that way.
Bombing a dam is damn hard. seen from the air they are very small targets. And they are concrete and over built. even if you hit the top you have not done much damage. to destroy the dam you have to hit is near the bottom where the water pressure is high. hence the need for a raid on the ground: to hard to hit.
Enter the skip bomb. the Skip bomb is a spinning cyllindric bomb dropped in the water above the dam. it skips, skips, skips and slams in to wall of the dam. but it does not explode. instead the back spin makes it claw its way down the side the dam where it detonates near the bottom.
there's lots on the web on this, including . http://www.pbs.org/wnet/secrets/case_nazidams/
FPGAs worked pretty well here because they could handle the fire hose data rate from front to back. Their final output was a small nuumber of processed bytes so that could then go to a normal computer for display and storage.
the problems the engnieers had was two fold. first in the early chips there were barely enough gates to do the job. and in the later ones form xylinx there were plenty of transistors but they were really hard to design properly. the systems got into race conditions were you had to use software to figure out the dynamic proerties fo the chip to see if two signals would arrive at the next gate in time to produce a stable response. you had to worry where on the chip two signals were coming from. it was ugly and either you accepted instability or failed prootypes or you put in extra gates to handle synchronization--which slowed the system down, and caused you to waste precious gates.
still my impression at the time was WOW. here is something that is going to work, its just a matter of getting better hardware compilers. Since then Los Alamos has written a C compiler that compiles C to hardware and takes into account all these details it used to take a team of highly experienced engineers/artists to solve.
Also someone leaked a project going on at National Instruments that really lit up my interest in this. I don't know what ever became of it, maybe nothing. but the idea was this. National instruments makes a product called "labview" which is a graphics based programming language whose architechute is based on "data flows" rather than procedural programming. in data flows, objects emitt and receive data asynchronously. when an object detects that all of its inputs are valid data it fires, does its computation (which might be procedural in itself, or it might be a hierarchy of data flow subroutines hidden inside the black box of the object) and emitts its results as they become valid. there are no "variables" per se just wires that distriuted emitted data flows to other waiting objects. the nice thing about this language is that its wonderful for instumentation and data collection, since you dont alwayd know when data will become available or in what order it will arrive from different sensors. Also there is no such thing as a syntax error, since its all graphical wiringing, no typiing, thus it is very safe for industrial control of dangerous instruments.
anyhow the idea was that each of these "objects" could be dynamically blown onto an FPGA. each would be a small enough computation that it would not have design complications like race conditions and all the objects would be self timed with asyncronous data flows.
THe current state of the art seems to be that no one is widely using the C-code or the Flow control languages. instead they are still using these hideous dynamical modelling, languages that dont meet the needs of programmers because they require to much knowledge of the hardware. I dont know why. maybe they are just too new.
However these things are not a panacea. For example, recently I went to the FPGA engineers here with a problem in molecular modeling of proteins. I wanted to see if they could put my fortran program onto an fpga chip. the could not, because 1) there was too much stored data required and 2) there was not enough room for the whole algorithm. So I thought well maybe they could put some of the slow steps on to the fpga chip. for example, given a list of 1000 atom coordinates, return all 1 million pair wise distances. This too proved incompatible for a different reason. When these fpga chips are connected to a computer system the bottleneck of getting data into and out of them is generally worse than that of a cpu (most commerical units are on PCMCIA slots or the PCI bus). thus the proposed calculation would be much faster on a ordinary microporcessor since most of the time is spent on reads and writes to memory.! there was however one way they could do it faster and that was to pipeline the calculations say 100 or 1000 fold deep. so that you ask for the answer for one array, and then go pick up the answer to the array you asked about 1000 arrays ago. this would have complicated my program too much to be useful.
these new FPGAs are thus exciting because they are getting so large and have so much onboard storage and fast internal busses that a lot of the problems I just mentioned may vanish.
My knowlege of this is about year out of date so I apologize if some of the things I said are not quite state of the art. But I suspect it reflects the commerially avialable world
the 1$ is just the standard minimum for a contract. do you suppose he gets health benefits worth more than $1 too. i'd say so.
the thing with steve is that he loves running apple and it shows. that's why I did not worry about voting stock options for him. I did not have the sense he was going to pull an enron, goose the stock price and bail. On the other hand I was a bit nervous about the rest of the board. What made me less owrried was that some of the principles ate the time was larry ellison and the head of genetech. These people are also into their own bussinesses in the same way steve is into his. So i felt reassured.
maybe i'm wrong basing investment decisions on personality, but its the only stock I own I have not lost money on in the past several years.
But the tone of this post, that the $1 salary is a hypocritical lie just does not past the reality test. only a naive dupe would think that was his only compensation.
I'm guessing the north pole is dry ice still. that means if the planet warms a bit we get club soda. I'll drink to that.
what is the practical range of a wifi card? I'm talking here about with real houses and stuff. mine does not seem to reach the room on the far side of the house. (I have concrete interior walls.) So I know it wont reach my neighbor on the far side of that room.
on top of this my 2.4Ghz phone does an excellent job of jamming the connection. I suspect the microwave deteriorates the signal too. Thus I have real worries about if networks based on wifi are practical at the micro-isp level.
Another question is if a wifi pcmcia card, and a typical link-sys or airport basestation unit have the same range. That is to say if I run software basestation on my mac does this have the same range and throughput as a real basestation?
comments?
The article divides up usage patterns of the back button in to modalities. the main one being jumping back to the portal entry page after burrowing down a thread. this is exactly what the SAFARI snapback does.
but since you brought it up let me address one small point in your comment.
Thus there still isn't any known adaptive mechanism to get to DNA/RNA.
While of course we cant say "whence dna" there are a lot of good leads at the moment. The most promising in my opinion is the growing realization is that RNA can do both the functions of DNA and Proteins. That is it is an information storage system that can replicate itself and edit itself, and it can form chemically active self-folded structures just like proteins. In fact in a perfectly benign environment its not absurd to suggest that life could be composed entirely out of RNA and small naturally available molecules.
The reason life could not currently be composed out of RNA is that its a hostile world and a lot of the precursur molecules dont exist anymore (other animals used them up). RNA is chemically unstable and easily digested. plus its reaction rates are too slow making it a lousy catylist for many activities. On the other hand in a primordial world, without hostile agents, and no competiton one has all the time in the world to wait for a slow catylist. Its the poker hand again: a pair of twos wins if everyone has has dick. thus its not unthinkable that RNA is the missing link. the fact that RNS still is the middle man speaks volumes. But we will probably never really know unless we find some alternate biospace that evolved differently (the possible discovery of nanobes in deep mines and maybe asteroids comes to mind).
Now the sentence in my discourse you keyed on ("The answer is that being adaptive can beat being the best." ) could obviously be made into a book length discussion. I probably could have chosen my words more carefully too. perhaps I should have said "being adaptive can beat being the most optimally adapted organism to a current environment". For example, if every one lives on mice then the one with the perfect irreducibly complex mouse trap may be the dominant species, but a crappy one that also floats or catches fish on out of every thousand tries might be a more adaptive but marginal species in the present environment (e.g. imagine a speer planted in the ground that requires the mouse or fish to fall on it. Not exactly irreducibly complex, but definitely adaptive. one does not need the perfect mouse trap to get started if a shift (e.g. waterworld) in environment suddenly gives you an advantage.). There are others who have actually taken behe mouse trap argument literally and shown one can infact reduce it.
but I'm getting off point here.
I'm waiting for it to reach X12
Or to put it another way, people with a family history of being prone to genetic mutation, or behavioural disorders, may in the long long long term have a greater influence on the genetics and sociology of future humanity, than those beautiful, well behaved people. What I cant decide is if this slash dot community represents a breeding place for diversification under harsh conditions or is a swarm fuzzy well balanced world for a particularly obnoxious phenotype and is thus not promoting its own evolution.
this reminded me of an older paper that tried to rationalize why optimal growing conditions does not seem to favor rapid evolution of a species. That is what scant evidence there is, it appears that evolutionary diversity and advancement occurs under not the optimal growing conditions but rather in the harshest. e.g. at the highest altitude, hottest temperaures or any place life struggles to survive.
While its obvious that harsh conditions by themselves impose evolutionary pressure this does NOT promote diversity--after all that pressure only is placed on genes that govern adaptation to the environment, and even there there is generally a narrowing of the gene pool not an expansion.
No instead the diversity arises because you have left your old balanced environment and predators, and thus have LOST the finely honed evolutionary pressure on those genes. thus you can evolve semi randomly with little selective pressure, leading to diversity. Another factor leading not to diversity but to rapid differentiation is that when these new traits that have nothing to do with survival get chromosomally linked to the features that enhance a species survival in the harsh environment, they get amplified.
some people call this the poker hand effect. You dont need a royal straight flush to win. all you have to do is beat your opponents. Or to put it another way if you are trying to live in a chemical wasteplant out flow, you dont have to generate a a very good enzyme for digesting plastics, anything that is better than your competitors is good enough for now. You can evolve it more later.
this explanation is perhaps the simplest and best answer to creationists who want to insist that life is too complex a process to spring into existance fully developed (.e.g. behe's mouse trap argument). The answer is that being adaptive can beat being the best.
anyhow its interesting that a species poised to exploit an opportunity will evolve faster than one that dominates its native environment.
Yeah, that could replace e-mail as way of communicating. Just think about it. instead of typing you use your voice.
Twirlip, how do we deal with the case insensitivity in UFS. it occasionally happens that a linux package will contain a directory with two files like "HEAD" and head or ReadME and readMe of "configure" and CONFIGURE. if you unpack this on an HFS+ system the files will overwrite each other. How does one escape this in HFS+? it should of course not happen on an all mac network but the xserve is intended to be nfs and smb connected to widows and linux machines who will no know they are on HFS+. Has apple installed some magic fix in the HFS+ system. I asked an apple tech and they said no this was still a problem and suggested UFS.
any how I was mistaken--the apple web page did not mention the raid 5 so I assumed it was just the same as the old 1-U xserve. sorrty for the misinfomation
A while ago I bought two xserves to act as diskserves to a linux cluster and to backup my desktop macs. I bought these machines because I felt they were a good deal. I got bids on several pc based linux disk servers, as well as several NAS boxes. I was comparing 480GB machines. a high quality generic brand (supermicro) with scsi disks and dual Gigabit ran about $8000 (at the time). The lowest bid I got was $5000 but the unknown quality and reputation of the vendor was not satisfactory. The mac xserves ran just under $7000 using IDE disks with 4 indepenedent masters (out performs the scsi). Additionally the mac had other nice features such as: 1U versus 3U. hot swap. advanced admin tools.
I bought both the apple and supermicro based systems in the end and can compare them directly. . after I unpacked the mac I was even more impressed with the high quality construction and ease of access to the interior in comparison.
first the good news:
What really made it for me on the macs was the fact that I had to hire a sysadmin to correctly set up my linux box with load balancing, Ldap, mail server, and moreover to keep it patched and to monitor it. On the macs I set them up myself. No detected problems with load balance. and the mac tools let you set up nearly all the services you might want with an intuitive gui.
Actually, I had a few snags but even here I have to give apple a good reprot card. they chancged how they did network admin right when I got my box. so all the documentation was for the obsolete tools and none for the new. So I got things really screwed up with services I could not turne off once turned on. The machines would gag when they could not find their ldap serviers or when they were cut off from the internet. But I called apple on the free service plan. after a ten minute wait on came a guy who really knew his stuff and spent about an hour with me getting all of my various problems sorted out and teaching me the new system. And in fact the next day he called me back! said he had another idea about a question i had asked him. I was really impressed on the customer service. its much better than for my other mac computers. Since then Ive had mac people call me back three times with ideas for me. Now that the new tools are better docuimented (still a few gaps), life is easy.
perhaps the best feature is the software update feature. I get patches and new tools delivered automatically and have the confiudence they wont screw up my all apple configuration. thus I still have not needed a sys admin. At the purchase time I had considered some NAS boxes (e.g. iomega,snap...) for the purpose of making sys admin simple. But these things have lousy throughput for the price and aren't versatile computing machines.
Now the bad news:
However I have had three problems with my xesrves that I dont have with my linux box.
first no raid 5. that's absouluetly maddening. I bought a raid 5 solution from a third party but I'm nervous it wont be effieicnt or it will die someday when I do a self-update that makes it incompatible.
second, and this compounds the above problem is the UFS/HFS+ dichotomy. while macs do run UFS, they dont do it effieicently or with any advanced features like journalling. Moreover the OS and some mac apps wont work unless they are on UFS. so you always have to have a HFS+ partition. but wait! you cant partition a raid disk with different file systems (on apple) so this means if you want to have any hfs raid the whole disk has to be HFS+. on our four disk Xserve this means I ended up with two disks RAID1 HFS+ and and two disks UFS raid 1- a whopping 120GB of UFS out of my 480GB (raw) can be UFS. yuck!. fortunately there is now a partionalble raid 5 soultion from a theird party which fixes this issue. (the reason I wanted UFS, was because even though I lost some effieiceny i wanted no surprises for my linux systems due to the filenaming case sensitivity)
The third problem I have had is that while the admin tools are wonderful and run on remote machines, there are a few tools and apps that will not run remotely. for example, if I want to use the GUI software update remotely, I cant. I have to use the terminal CLI tool. This is not too bad, but its just an example. if you use other gui tools, like brickhouse firewall or whatever, you have to go to the terminal attactched to the machine.
My work around for this is to use OSXVNC which does the job. However there is a catch I dont like. You cant use osxvnc on a headless mac. that is you have to have a display device connected to the mac to use osxvnc!! there's no way I want to have a display for each mac xserve. Of course I could use a KVM switch but my preference would be that it should be unneccessary for remote admin. my work around here is that I can fool the macs by briefly connecting a display to them after boot. I can then unplug the display and OSXVNC will still work on my headless mac.
My conclusion is that apple has a wonderfulhigh quality machine. And it will work perfectly for you if you dont require UFS or remote admin of GUI based apps. When I bought my system I had just had a bad experience with 20 athalon servers that had died from heat delamination of the fans and were unstable due to current glithces from the cd roms. I was thus very risk averse. when I bought the apples I knew I was buying peace of mind, and not paying extra for it. I had no idea what good customer service I was going to get. PLus I did not realize I could also buy a complete replacement part kit (down to the motherboard) to have locally. Since my experience with their customer service I bought the extened warantee. its lot cheaper than a sys admin.
when mac comes out with native raid5 and someone writes a VNC that can run headless all will be well.
p.s. I apologize to the few slashdotters who are outraged when a post is reposted. this review was posted as a sub comment to a sub topic on an earlier artilce today. rightfully it belonged in this thread so I reposted it here.
A while ago I bought two xserves to act as diskserves to a linux cluster and to backup my desktop macs. I bought these machines because I felt they were a good deal. I got bids on several pc based linux disk servers, as well as several NAS boxes. I was comparing 480GB machines. a high quality generic brand (supermicro) with scsi disks and dual Gigabit ran about 8000 (at the time). The mac xserves ran just under $7000 using IDE disks with 4 indepenedent masters (out performs the scsi). Additionally the mac had other nice features such as: 1U versus 3U. hot swap. I bought both systems in the end. after I unpacked the mac I was even more impressed with the high quality construction and ease of access to the interior.
What really made it for me on the macs was the fact that I had to hire a sysadmin to correctly set up my linux box with load balancing, Ldap, mail server, and moreover to keep it patched and to monitor it. On the macs I set them up myself. No detected problems with load balance. and the mac tools let you set up nearly all the services you might want with an intuitive gui.
Actually, I had a few snags but even here I have to give apple a good reprot card. they chancged how they did network admin right when I got my box. so all the documentation was for the obsolete tools and none for the new. So I got things really screwed up with services I could not turne off once turned on. The machines would gag when they could not find their ldap serviers or when they were cut off from the internet. But I called apple on the free service plan. after a ten minute wait on came a guy who really knew his stuff and spent about an hour with me getting all of my various problems sorted out and teaching me the new system. And in fact the next day he called me back! said he had another idea about a question i had asked him. I was really impressed on the customer service. its much better than for my other mac computers. Since then Ive had mac people call me back three times with ideas for me. Now that the new tools are better docuimented (still a few gaps), life is easy.
perhaps the best feature is the software update feature. I get patches and new tools delivered automatically and have the confiudence they wont screw up my all apple configuration. thus I still have not needed a sys admin. At the purchase time I had considered some NAS boxes (e.g. iomega,snap...) for the purpose of making sys admin simple. But these things have lousy throughput for the price and aren't versatile computing machines.
However I have had three problems with my xesrves that I dont have with my linux box.
first no raid 5. that's absouluetly maddening. I bought a raid 5 solution from a third party but I'm nervous it wont be effieicnt or it will die someday when I do a self-update that makes it incompatible.
second, and this compounds the above problem is the UFS/HFS+ dichotomy. while macs do run UFS, they dont do it effieicently or with any advanced features like journalling. Moreover the OS and some mac apps wont work unless they are on UFS. so you always have to have a HFS+ partition. but wait! you cant partition a raid disk with different file systems (on apple) so this means if you want to have any hfs raid the whole disk has to be HFS+. on our four disk Xserve this means I ended up with two disks RAID1 HFS+ and and two disks UFS raid 1- a whopping 120GB of UFS out of my 480GB (raw) can be UFS. yuck!. fortunately there is now a partionalble raid 5 soultion from a theird party which fixes this issue. (the reason I wanted UFS, was because even though I lost some effieiceny i wanted no surprises for my linux systems due to the filenaming case sensitivity)
The third problem I have had is that while the admin tools are wonderful and run on remote machines, there are a few tools and apps that will not run remotely. for example, if I want to use the GUI software update remotely, I cant. I have to use the terminal CLI tool. This is not too bad, but its just an example. if you use other gui tools, like brickhouse firewall or whatever, you have to go to the terminal attactched to the machine.
My work around for this is to use OSXVNC which does the job. However there is a catch I dont like. You cant use osxvnc on a headless mac. that is you have to have a display device connected to the mac to use osxvnc!! there's no way I want to have a display for each mac xserve. Of course I could use a KVM switch but my preference would be that it should be unneccessary for remote admin. my work around here is that I can fool the macs by briefly connecting a display to them after boot. I can then unplug the display and OSXVNC will still work on my headless mac.
My conclusion is that apple has a wonderfulhigh quality machine. And it will work perfectly for you if you dont require UFS or remote admin of GUI based apps. When I bought my system I had just had a bad experience with 20 athalon servers that had died from heat delamination of the fans and were unstable due to current glithces from the cd roms. I was thus very risk averse. when I bought the apples I knew I was buying peace of mind, and not paying extra for it. I had no idea what good customer service I was going to get. PLus I did not realize I could also buy a complete replacement part kit (down to the motherboard) to have locally. Since my experience with their customer service I bought the extened warantee. its lot cheaper than a sys admin.
when mac comes out with native raid5 and someone writes a VNC that can run headless all will be well