It doesn't matter whether or not there is/was/was ever a backdoor. No matter if it's entirely true or not, the public is set on the idea that "!seineew era sreenigne epacsteN" is a huge security problem. At least it's more tangable than buffer overflows (which the public at large tend to care nothing about - look at AOLIM).
At the very least, the idea is that the string shouldn't be in there no matter what it does (and yet we seem to care nothing about easter eggs) so why not go ahead and use it to push an advantage of open source? It's a foothold in Microsoft's own game! M$ does this sort of thing all the time (look at Mindcraft).
While I do agree that ESR should probably have clarified that this particular time the security implications of "!seineew era sreenigne epacsteN" are minimal, I do not think that it's ever a bad time to point out the advantages of OSS, especially when the public is more prone to accept and agree with it!
Well, look at it like this. Let's say you have a metal mesh antenna and you need to shield the back of it because you want to put another antenna behind it. If you put the lead foil or whatever you're using directly on the back of the antenna, you are modifying the antenna (even though lead foil would only be destructive modification) and it would be illegal. In this case, you are modifying a certified piece of equipment.
So in the ISM band where the antenna and the radio and all other equipment are certified TOGETHER, if you unscrew one antenna and attach another one, you may be operating with a modified unit and thus would be illegal.
But you are backwards. It is not illegal to sell an uncertified device. Usually you see these for sale as "for use only in europe or canada" or whereever.. Syncronized frequency hopping radios are an example of hardware that is often sold to US people and used in the US even though it's technically illegal (as you can clog bands with them)
I should say again that I still don't necessarily agree with this and I do not mind seeing people venture into uncertified territory responsiblly. In certain cases, there are actually better uncertified antennas for 802.11 than the ones that are certified. Phased-gate-array antennas come to mind, and I have never seen a 802.11 radio with a certified PGA antenna.
Get off your asses and certifiy this stuff if you're going to make ridiculous laws, FCC!
Direct line of site is going to reduce your signal only based on the equasions for free-space loss. And it's not just LOS, but 60% of your fresnel zone has to be free too otherwise you're going to take a hit.
Indoors, you have problems shooting through walls (drywall gives about 3dB loss... so does glass). Insulated walls and coated glass give about 6-8dB loss, etc. A row of trees outdoors gives about 3dBi of loss.
The major problem indoors is multipath propigation (where the signal bounces off of walls and stuff. I had to WLAN a room that had angled mirrors around lightbulbs on the ENTIRE ceiling. It took *FOUR* access points (one in each corner) to get rid of multipath problems (the didnt really want to change their mirrored ceiling!
That is because a lucent wavelan card doesn't put out 30dBm of power. It puts out something like 17 or 18. I don't know the specifics on this hardware because I use different brands.
Actually, FHSS (Spread spectrum frequency hopping) hops to a different frequency after a set amount of time. In 802.11 frequency hopping occurs on 76 distince frequencies in the 22Mhz ISM band centered at 2.4GHz. The hops are psuedo random and the radios are very expensive to jam. Even when you turn on your microwave, you only interfere with one or two hopping frequencies, so you notice maybe a 5% reduction in bandwidth and a couple retransmits but nothing too bad.
And as for the government's being concerned nonsense they are very concerned and I've seen quite a number of people get busted on 2.4GHz stuff. I dont know where you get off saying that sharing this band with microwave ovens is difficult. Remember that this is a 22MHz band and your microwave oven transmits about 50 feet or so. It's radiation curve is also very steep so it only interferes with maybe 1/50th of the band. Plus, microwaves have a 50% duty cycle on high so even when it's on full-blast it only interferes half the time!
Well, read my other post where I clarified this It's here.
Anyway, you can't tramsmit 30dBm+45dBi on this setup legally. To use 45dBi EIRP you'd have to have only 22.5dBm power maximum. Plus, you'd probably never make the link since that much gain would affect the shape of your radiation pattern. It would extend directly from the directional antenna in the shape of what amounts to a very long thin, pencil.
Think silly putty. Both antennas have to be inside the blob to make the link. The amount of silly putty is the dBm and the dBi is how much you stretch it out. You should check out some propigation patterns at even 24dBi. They are pretty skinny necked little buggers. I can't even imagine aiming a 45dBi antenna. Sure if someone else put their radio in that line it would be useless but then again, that propigation path is very small.
In answer to your first question the 2.4 gig stuff is actually ISM band stuff. The ISM band is a 22MHz band centered around 2.4GHz. And yes, 802.11 radios talk all throughout this band.
That original reg was written a long time ago primarily so that "microwave" devices (like your microwave oven) and similar medical equipment (scary thought) would have a free high-frequency range to interfere with legally. Put your wavelan on top of an operating microwave on high and you will see about a 50% reduction in bandwidth.
The redone spec allows this sort of use, or obviously there wouldn't be a bazillion companys selling ISM-band equipment today including cordless telephones and wireless lan equipment. See my other post (it's long and +5) for a layman's rundown of the law as it applies to wlan's and ISM stuff in general.
EIRP is the sum of dBm and dBi, and of course is measured in dB. To the recieving antenna they really are pretty much equivalent. The maximum dBm is 30 and the FCC extended the regulations for ISM band equipment to allow for an extra 6dBi of gain on top of the 30dBm. Plus, they allow you to add 6 dB of antenna gain (isotropic radiation -- dBi) for each time you subtract one dB of power (dBm from your setup before it reaches the antenna -- you can reduce the power output of the radio or add more cable, etc).
I have all the relevant calculations, but they don't make much sense in ASCII and since there really isn't a very good implementation of math rendering in a popular browser yet, I'll forgo that junk and just say that you can radiate a signal that would be comprable to a 4W signal legally in the ISM band.
Key testing is going to take a while too over 1Mb/s which is the speed at which the WLAN authentication is done.:) Unless you capture a packet and try to decode it brute force. Either way, hope you have a few hundred years or a very large supercomputer.
I am curious to know what brand card you have. I haven't seen one that lists ESSID's! Please let me know. Thanks,
The radios you have described at 2Mbps are Frequency-Hopping spread spectrum not direct sequence.
Frequency hoppping spread spectrum (FHSS) radios deal with interference very well but the 11Mb radios are not frequency hopping they are Direct sequence (DSSS) and if you get two conflicting DSSS systems on the same channel (of which there are only 3 non-overlapping you have total interference! The radios will share bandwidth if they're supposed to be on the same WLAN (Same ESSID) and the same brand but if they are different ESSID's, and especially if they're different brands, they are most likely going to cause each other TOTAL INTERFERENCE. I deal with this problem every day attempting to co-locate 11Mb DSSS equipment. It's a real headache. I'm just glad some IDIOT hasn't gone and started soldering on his airport in between some of my DSSS beams.
Ahem. Actually it is *NOT* FCC legal. It seems that there really are very few professional wireless networking people commenting on here, and to those of you who are reading this and feeling as pained as I, this reply is for you!
I will explain the regulations here and hopefully clear up a lot of other misconceptions as well.
The fines for this stuff, BTW, are very very large especially if you muss up and they get you for spurious emissions or accidentally putting out 10W of power or the like. And when you're blasting this thing over a radius of 3 miles, it's not like you're being quiet about it!
2.4 gHz Telephones, 802.11 Wireless Networking, various medical devices, and microwave ovens transmit in the public domain ISM band. This band is a 22Mhz frequency range centered at 2.4gHz. ISM-band equipment may have a total EIRP (Effective Isotropic Radiated Power) of 36dB.
This EIRP number is calculated as a maximum of 30dBi with up to 6dBm of gain at this power. The nice catch is that for every dBi of power you subtract, you can add 6dBm of gain!! This power output can actually be equivalent to about 4W of legal power depending on your antenna gain... as long as your dBi output is less than 30dBi.
So, regulation-wise, yes. It is possible to use 2.4gHz 802.11 radios to go up to 30 miles legally, but why cant you modify your WaveLan/AirPort to go 30 miles? The reason is this:
Because the ISM band is a public-use band, The radio, the antenna, the cable, and the amplification equipment MUST ALL BE CERTIFIED BY THE FCC AS A SINGLE UNIT!!! This means, that if a particular high-gain antenna and/or amplifier is certified to be attached to the Apple AirPort (of which there are none except its internal antenna) then you may legally use it.
The WaveLan range extender is certified for use with the WaveLan equipment, but the apple airport is not a lucent WaveLan Silver in the eyes of the FCC. Thus the wavelan range extender is not certified for use on the airport -- which is what the first modification describes.
The second modification describes attaching 'standard' antennas to the AirPort by manufacturing a special cable that will let you attach to the special connector on the WaveLan card. I should note here that the reason there is a special connector on this card is so that only certified antennas may be connected to it without voiding its warranty and lucent/apple's responsibility for its performance! Am I beginning to make sense here?
The point is simple. When you open the AirPort or your WaveLan card and attach antennas or amplification that is not certified for use with the radio, you are breaking the law. Now, I personally don't really believe in the "certified as a unit" crap the FCC dishes out on public frequency equipment, but it is still the law.
Now, to raise another point.
11Mb radios are currently all DSSS. There aren't any frequency hopping 11Mb radios yet, although the 802.11 standard provides for them. The DSSS radios may use channels that are 2mHz apart, giving them a total of 11 usable channels in the 22MHz ISM band. The problem with this is that there are only 3 non-overlapping channels So to all of you out there who just think that you can extend your range all to hell and back, don't be suprised when four other people in your zip code do the same thing and find that none of you can even use your DSSS WLAN's!
Frequency hopping is another story altogether. FHSS 802.11 radios operate at up to 2Mb and you can co-locate 17 of these radios in one room and you won't interfere! If you want to be very cool to other WLAN users in your area, do check out FHSS radios, as they are much more practical for most WLAN applications. Honestly, if speed wasn't such a big deal to everyone and their dog then we might not even have 11Mb wireless until the Frequency hopping hardware catches up.
Please be responsible with your 802.11! If you don't, you're going to turn the wireless networking industry back to licensed microwave transmitters, and you'll probably just piss yourself off because all the public spectrum is gone.
Well actually, what you have just described is three (maybe four) seperate attacks. First, you need the ESSID to talk on the WLAN before you can even authenticate. The ESSID is not too difficult to discover if you have physical access to another piece of equipment on the network (especially with the apple stuff), but if you have to crack it, it's similar to a password attack. Then you need the WEP keys for auth. The WEP keys are usually password protected in the configuration software, so unless you desolder the EEPROM and read the contents out, you will have yet another password to crack. Finally, after you are authenticated with WEP then you will have to break the stream cypher. Oh, and by the way, it's 2^128 keys not 128^2. Your number of keys falls short by about 3.4 x 10^38. And brute-forcing WEP is going to be a pair of 56 bit keys if you have to do that. Needless to say, your'e going to spend quite a while breaking into this one. And this is why wireless is more secure than wireline, even without stream encryption. Funny how banks seem to get really paranoid when we tell them that stream crypto isnt really necessary on their wireless links when they aren't requiring wireline crypto on their leased lines. Of course, explaining the whole mess to them usually gets me a nice sale of some 3DES routers:)
I use an 8 port Cybex AutoView 200 with the built in second console port for a LongView reciever.
You can set up three tiers of 8 port cybex 200's to control up to 512 systems from one menu. Also, for remote administration, the 200 has support for one local console (plugged directly into the switch) and a second console up to 500 feet away over standard cat 5. The two consoles can control different systems independently or (this is cool --) the same system at the same time. The colors on the "remote" screen faded and stuff at first, but i ran some shielded cat5 with shielded ends and hooked the remote console up with a flat panel monitor and it is perfect 400 feet away.
Actually, I'm predicting that in 10 years the present designs for both PC's and mainframes will reach a bit of common ground to give us more functional scalable computing. The same components will make up both both consumer and enterprise computing hardware and the amount of computing power will be directly proportional to how much money someone decides to spend.
The current design of mainframes has many advantages that the PC can benefit from on a smaller scale - hardware virtalization, componentized architecture. Likewise, the PC has some advantages that the mainframe market is going to have to take heed of in the next 5 years or so in order to stay alive - real-time interactivity, extreme flexibility, and standards-based hardware design.
The key here is architecture interoperability, and I am simply predicting that within 10 years there will be no more bold dividing line between "PC" and "Mainframe."
They accomplish this, generally, by a lot of virtualization in HARDWARE, while normal PC's do this virtualization in software using stupid tricks like time-sharing (and calling it multitasking)
The PC, though, is about to pull up its pants, so to speak. Crusoe is already virtualizing instruction sets of all the fanciest desktop processors. SMP is going to make a big leap when virtualization fully leaks into the desktop. This will probably happen inside of two and a half years.
Either way, I am projecting that the life of the mainframe is 10 years, maximum. Likewise, the paradigm of desktop computing as we know it is also going to be gone in this same span of time. Both will probably be replaced with some sort of scalable, componetized architecture that eliminates (or greatly reduces) obselescence, improves reliability, and increases performance.
Someone already mentioned Mac-On-Linux. There are a couple more Mac emu's for LinuxPPC in development, though. SheepShaver is working on a Linux/PPC port of their popular BeOS/PPC product. And ARDI has just released a version of their Executor product for Linux/PPC. Executor doesn't emulate PowerPC, but it does emulate a 68040 quite well, and it doesnt require Macintosh ROM's, a real Macintosh, or MacOS to run Mac software.
OK. Here's another take. Many newer games using 3D API's have to be written with resolution independence. For instance, on an old 3DFX Voodoo, you're not going to be able to push 30fps in the newest games unless you run at 640x480 or maybe 800x600. But on your brand spanking new GeForce 256 DDR you can do 1280x1024 at like 60 fps.
I don't really understand how everything under the hood works, but it appears to me that when a game needs to display 2D graphics, sprites, or entire 2D UI's, it makes calls to the 3D libraries, loading these graphics as textures that the accelerator can then scale, rotate, and all that other fun stuff. Load up Quake 3 and look at the main menu. The text is the same size no matter what resolution you're at and unless you're in some absurdedly high resolution, it doesn't pixelate, and the graphics card automatically anti-aliases the pixels.
Display Postscript, Display PDF, and other forthcoming display technologies rely a lot on software and still treat the computer display as a raster medium. These will be interim solutions, but if the proper hooks aren't put into these software components for hardware acceleration, things like Display PDF will overrun the processor at very very high resolutions.
How about this? Let's treat the video memory area in the graphics card as a canvas and draw vector graphics in it. These will naturally include bitmaps with physical size information, and even a legacy "raster canvas" mode to accomidate legacy applications. Then all that has to happen is the graphics card does the rasterizing to whatever absurd resolution you need and pipes it to the display.
A few things this implementation has the ability to do:
1) Support everything NOW. In legacy modes, you'd get anti-aliased scaling, much like when I change my resolution on this LCD monitor in front of me to 640x480. Sure, you wouldn't get the benifit of 200 ppi, but at least you would have a crisper screen to look at (one of the things that annoys me most about my flat panel is that you can see the individual Pixels and the grid in between them)
2) Take a lot of the graphics burden off of the CPU -- the performance increase from the modifications made to DirectX 7.0 to accomidate the GeForce and a "GPU" in general really beg for the same kind of GPU idea to migrate back to 2D, where it will be needed to support massive resolutions needed in the future. Gradients, scrolling, and moving entire solid windows and widgets around are some of the most CPU intensive operations that can be done (check your meter while running E with all the bells and whistles on!) This are things that should be done by the video card anyway. Let's see some people start putting hooks in there software and OS's to allow this! Stop thinking in pixels already!
3) Support legacy apps on new software/hardware in the future. Load a rater-drawn app into a texture buffer and a virtual "screen" that has pixel dimensions, then scale those pixels on the canvas appropriately.
So anyway, I guess we'll see now how this idea will hold up.
This is the German comment babelfished for other people like me who are interested.
My objection over LinuxONE LinuxONE had its saying, and this is meins. Which follows, a call is to the complaint on from us, which are interested -- large enough number for challenging vitriolic acceptance LinuxONE's over grade of transmission performance. I must protest to LinuxONE's use of bad Prudisharten to obtain its sadistic targets. This acknowledgment indeterminateness the demonstrability regarding an external to accompany objective reality is concerning a crisis our ability, to be known had that the only way, which is I LinuxONE perhaps forgive can, if it says the truth and forms returning. No matter how much discussion and analysis occur, an organization, which would like to receive in front, should tries, to understand the extensive consequences of its jokes. LinuxONE never had these training bodies. It always does, what would like to do and to figures it be able to do it at the moment to be situated even from all possible problems which develop. LinuxONE's cronies it seems to struggle that it cannot do injustice. I know, because I experienced that personally. LinuxONE's lackeys is frequently intercepted trying to stamp brutishwhinges. Of course they refuse this, but all we know full recess that LinuxONE is not capable to use the English language effectively or correctly. LinuxONE's maneuvers disbursed themselves: squalid wrongmoderated liars and cheat something success in their efforts, in everyone had to already interfere otherwise affairs. It is far away well-known that LinuxONE's philosophies are based on somewhat deep-rooted Funktionseigenschaftstoerung. But I have a tendency, over which more sensationalsachen the fact that LinuxONE to, is shocking the things, things to report as, like it would like to lead substantial documents hidden from the public, until they become politically contentious. And I carry out the difficulty, which has the average person when coming to the grasps with that, but it the case is literal, which we begin to witness the absorbed effects of its new interpretations of the historical cases. It is person suffering from a brain injury, so that LinuxONE regulates debt for social printing, economic loss, or loss of the political energy on a target group their debt designed, supplies a highly simplified assertion. Or possibly I should say, it am political false. If one needs a character the fact that LinuxONE is uncertain regards you that it forms a virtue of the not again-good-closing disturbance. Not too belabor the point, but LinuxONE states that its requirements are approximately hurt not worth receiving. I react that there is another page to the output. An old joke explains from the optimist up to now, which away from a building 60-story and, since it whizzes behind the 35th stick falls, " proclaims, so well! ", but such blind optimism, which henchmen LinuxONE's, is not over to think caused that they can animate a Arcadian behind that again existing ducks never. And that, in my opinion, is our real problem.
A Javascript OnMouseOver inside of an Anchor tag can change the apparent destintaion of a link by changing the text in the status window. So unless you like digging through the page's HTML and checking out the link you're clicking then this isn't really verifiably secure.
I for one think this is a stupid feature of javascript. I want the statusbar to tell me what the link is doing. A webpage shouldn't have the ability to screw with my browser's status bar! At least this should be a javascript option -- "Restrict Statusbar control" -- as other people have pointed out -- on and off aren't enough control!
How you people so quickly forget bringing about your own demise, and how quickly you defend companies who really aren't even your friend!
When Windows Media Player's streaming was first incarnated as Microsoft NetShow, MS worked with Xing to deliver players for damn near every single platform out there including Linux. In fact, I believe it was their second piece of software for Linux after the FrontPage extentions.
Now, we have everybody complaining about how MS is becoming more commonplace and RealPlayer is the only (large-market) solution still available under Linux.
Let me ask you this: have you ever tried to license a Real Media *SERVER* ? The licensing is absolutely ridiculous. Yes, I know they have the basic version but that's no good for any kind of commercial use. WMP's server-side application is included with IIS and has unlimited capacity. Hell, buying NT BackOffice (The entire operating system!) costs you half as much as supporting 100 streams of Real Media.
On top of that, WMP has better quality at the same bandwidth (at least for video). Just watch it or listen to it and it is not really a disputable argument. I'll give RealPlayer a chance too and say that it's more responsive when you want to skip around in a stream and it's way more fault tolerant.
Still, do you realize why you're complaining? You didnt support M$ tech when they tried to support *you*! I hate to have to defend them, but if the Linux/UNIX/Whatever people started driving and thriving in the streaming media market then we wouldnt look so second class to streaming media companies. M$ would probably still have a media player for Linux, and maybe some of their API's and CODECS would have opened up by now.
I am a bit annoyed with the defense of Real on this one. Getting the newest version of RealPlayer has always been delayed months (and close to 1 year on 5.0 and G2 -- they skipped 4.0 altogether), and until the release of at least 5.0 for Linux (which Real's web page makes nearly impossible to obtain) Real was an absolutely useless format if you wanted to do cross-platform video. Coupled with that, RealPlayer is a billion meg download that forces you to replace damn near every piece of multimedia software (at least on W32) -- I've stopped installing it on Windows. It absolutely is the most bloated, slow piece of garbage in the universe, and on top of that it (at least used to) gather up all of my personal info and beam it to RealNetworks!!
Please, stop supporting RealNetwork's trash! I would think that the/. community would be the first people screaming against this sort of thing!
First off, this is the first time I've ever jumped into a GPL debate, so cut me some slack if I'm wrong about things.
OK, these are indeed Litestep *modules* are they not? I'm of the opinion that a closed source shell could include in its distribution one of these modules (as long as the interface that the module hooked to was developed independently, and could be put under a commercial license) As long as the author of the non-gpl application acknowledged the modules GPL status and distributed them with source, what would be wrong with the main appilcation even depending on these modules?
My reasoning comes from looking at something like perl. There are plenty of people out there selling perl programs under a commercial license. Many of these are not open source and are run through a code-scrambler and then sort of "linked into" a perl binary so they are standalone. Many of these programs use GPL'd perl modules and interfaces to many other closed and open-source applications. E.g. Tk, ImageMagick, GD on the free software side and things like Win32::GUI on the commercial side. As I understand it, the perl application can be licensed under any terms as long as accompanying software is acknowledged as being developed independently.
Let's just for kicks say there is no deCSS and/or CSS wasn't feasably breakable. So I open up my DVD player and solder a few jumper wires from the data pins of the MPEG2 decoder chip, wire them up in some bizzare way to a computer, and press play. There we go. Decrypted DVD.
Look, MPAA. The assembly language code for deCSS is pretty much present in the BIOS or some other form of firmware inside of every DVD player ever made. Why don't you go sue every DVD player manufacturer? Why don't you go sue yourselves?
The normal transmission medium, however, is not where Tivo gets its program guide. The program guide gets downloaded via modem every three days or so along with the "Tivolution" digital magazine, software upgrades, and the like. The best part of this case is that even if the Tivo people have to change the device's operation somewhat to sidestep a bunch of bunk patents, they can!
I thought this article might be a good place to mention AT&T's DjVu image format. I have been working with their DjVu tools to develop quite a few web applications and they are phenominal. The format takes an image (it is designed for scanned documents) and creates an IW44 (wavlet compressed) background layer of the image and then creates a non-lossy overlay foreground layer to compress foreground components like text and lines.
The net result? 300 dpi full page scans in under 50K! When you print them, they are true enough to the original to justify the difference between a 5MB TIFF and the 50K DjVu.
I'm very glad to see some of the same technology being adopted into JPEG. I'm kind of dissapointed that the spec doesn't seem to allow the mixing of compression algorithm's inside of one image, which is what most all of the very very good compression methods seem to rely on -- the fact that different information in the same chunk of data can be optimally compressed in different ways. I mean, depending on the image, JPEG in some cases can smear wavlet-based methods into the dirt.
Slashdot Mirror
It doesn't matter whether or not there is/was/was ever a backdoor. No matter if it's entirely true or not, the public is set on the idea that "!seineew era sreenigne epacsteN" is a huge security problem. At least it's more tangable than buffer overflows (which the public at large tend to care nothing about - look at AOLIM).
At the very least, the idea is that the string shouldn't be in there no matter what it does (and yet we seem to care nothing about easter eggs) so why not go ahead and use it to push an advantage of open source? It's a foothold in Microsoft's own game! M$ does this sort of thing all the time (look at Mindcraft).
While I do agree that ESR should probably have clarified that this particular time the security implications of "!seineew era sreenigne epacsteN" are minimal, I do not think that it's ever a bad time to point out the advantages of OSS, especially when the public is more prone to accept and agree with it!
~GoRK
Well, look at it like this. Let's say you have a metal mesh antenna and you need to shield the back of it because you want to put another antenna behind it. If you put the lead foil or whatever you're using directly on the back of the antenna, you are modifying the antenna (even though lead foil would only be destructive modification) and it would be illegal. In this case, you are modifying a certified piece of equipment.
So in the ISM band where the antenna and the radio and all other equipment are certified TOGETHER, if you unscrew one antenna and attach another one, you may be operating with a modified unit and thus would be illegal.
But you are backwards. It is not illegal to sell an uncertified device. Usually you see these for sale as "for use only in europe or canada" or whereever.. Syncronized frequency hopping radios are an example of hardware that is often sold to US people and used in the US even though it's technically illegal (as you can clog bands with them)
I should say again that I still don't necessarily agree with this and I do not mind seeing people venture into uncertified territory responsiblly. In certain cases, there are actually better uncertified antennas for 802.11 than the ones that are certified. Phased-gate-array antennas come to mind, and I have never seen a 802.11 radio with a certified PGA antenna.
Get off your asses and certifiy this stuff if you're going to make ridiculous laws, FCC!
~GoRK
Well, yeah if you can line it up like a laser pointer! And if you're in a vacuum!
Direct line of site is going to reduce your signal only based on the equasions for free-space loss. And it's not just LOS, but 60% of your fresnel zone has to be free too otherwise you're going to take a hit.
Indoors, you have problems shooting through walls (drywall gives about 3dB loss... so does glass). Insulated walls and coated glass give about 6-8dB loss, etc. A row of trees outdoors gives about 3dBi of loss.
The major problem indoors is multipath propigation (where the signal bounces off of walls and stuff. I had to WLAN a room that had angled mirrors around lightbulbs on the ENTIRE ceiling. It took *FOUR* access points (one in each corner) to get rid of multipath problems (the didnt really want to change their mirrored ceiling!
~GoRK
That is because a lucent wavelan card doesn't put out 30dBm of power. It puts out something like 17 or 18. I don't know the specifics on this hardware because I use different brands.
~GoRK
Actually, FHSS (Spread spectrum frequency hopping) hops to a different frequency after a set amount of time. In 802.11 frequency hopping occurs on 76 distince frequencies in the 22Mhz ISM band centered at 2.4GHz. The hops are psuedo random and the radios are very expensive to jam. Even when you turn on your microwave, you only interfere with one or two hopping frequencies, so you notice maybe a 5% reduction in bandwidth and a couple retransmits but nothing too bad.
And as for the government's being concerned nonsense they are very concerned and I've seen quite a number of people get busted on 2.4GHz stuff. I dont know where you get off saying that sharing this band with microwave ovens is difficult. Remember that this is a 22MHz band and your microwave oven transmits about 50 feet or so. It's radiation curve is also very steep so it only interferes with maybe 1/50th of the band. Plus, microwaves have a 50% duty cycle on high so even when it's on full-blast it only interferes half the time!
~GoRK
Well, read my other post where I clarified this It's here.
Anyway, you can't tramsmit 30dBm+45dBi on this setup legally. To use 45dBi EIRP you'd have to have only 22.5dBm power maximum. Plus, you'd probably never make the link since that much gain would affect the shape of your radiation pattern. It would extend directly from the directional antenna in the shape of what amounts to a very long thin, pencil.
Think silly putty. Both antennas have to be inside the blob to make the link. The amount of silly putty is the dBm and the dBi is how much you stretch it out. You should check out some propigation patterns at even 24dBi. They are pretty skinny necked little buggers. I can't even imagine aiming a 45dBi antenna. Sure if someone else put their radio in that line it would be useless but then again, that propigation path is very small.
Hope this helps but it's probably clear as mud
~GoRK
In answer to your first question the 2.4 gig stuff is actually ISM band stuff. The ISM band is a 22MHz band centered around 2.4GHz. And yes, 802.11 radios talk all throughout this band.
That original reg was written a long time ago primarily so that "microwave" devices (like your microwave oven) and similar medical equipment (scary thought) would have a free high-frequency range to interfere with legally. Put your wavelan on top of an operating microwave on high and you will see about a 50% reduction in bandwidth.
The redone spec allows this sort of use, or obviously there wouldn't be a bazillion companys selling ISM-band equipment today including cordless telephones and wireless lan equipment. See my other post (it's long and +5) for a layman's rundown of the law as it applies to wlan's and ISM stuff in general.
~GoRK
EIRP is the sum of dBm and dBi, and of course is measured in dB. To the recieving antenna they really are pretty much equivalent. The maximum dBm is 30 and the FCC extended the regulations for ISM band equipment to allow for an extra 6dBi of gain on top of the 30dBm. Plus, they allow you to add 6 dB of antenna gain (isotropic radiation -- dBi) for each time you subtract one dB of power (dBm from your setup before it reaches the antenna -- you can reduce the power output of the radio or add more cable, etc).
I have all the relevant calculations, but they don't make much sense in ASCII and since there really isn't a very good implementation of math rendering in a popular browser yet, I'll forgo that junk and just say that you can radiate a signal that would be comprable to a 4W signal legally in the ISM band.
~GoRK
Key testing is going to take a while too over 1Mb/s which is the speed at which the WLAN authentication is done. :) Unless you capture a packet and try to decode it brute force. Either way, hope you have a few hundred years or a very large supercomputer.
I am curious to know what brand card you have. I haven't seen one that lists ESSID's! Please let me know. Thanks,
~GoRK
The radios you have described at 2Mbps are Frequency-Hopping spread spectrum not direct sequence.
Frequency hoppping spread spectrum (FHSS) radios deal with interference very well but the 11Mb radios are not frequency hopping they are Direct sequence (DSSS) and if you get two conflicting DSSS systems on the same channel (of which there are only 3 non-overlapping you have total interference! The radios will share bandwidth if they're supposed to be on the same WLAN (Same ESSID) and the same brand but if they are different ESSID's, and especially if they're different brands, they are most likely going to cause each other TOTAL INTERFERENCE. I deal with this problem every day attempting to co-locate 11Mb DSSS equipment. It's a real headache. I'm just glad some IDIOT hasn't gone and started soldering on his airport in between some of my DSSS beams.
~GoRK
Ahem. Actually it is *NOT* FCC legal. It seems that there really are very few professional wireless networking people commenting on here, and to those of you who are reading this and feeling as pained as I, this reply is for you!
I will explain the regulations here and hopefully clear up a lot of other misconceptions as well.
The fines for this stuff, BTW, are very very large especially if you muss up and they get you for spurious emissions or accidentally putting out 10W of power or the like. And when you're blasting this thing over a radius of 3 miles, it's not like you're being quiet about it!
2.4 gHz Telephones, 802.11 Wireless Networking, various medical devices, and microwave ovens transmit in the public domain ISM band. This band is a 22Mhz frequency range centered at 2.4gHz. ISM-band equipment may have a total EIRP (Effective Isotropic Radiated Power) of 36dB.
This EIRP number is calculated as a maximum of 30dBi with up to 6dBm of gain at this power. The nice catch is that for every dBi of power you subtract, you can add 6dBm of gain!! This power output can actually be equivalent to about 4W of legal power depending on your antenna gain... as long as your dBi output is less than 30dBi.
So, regulation-wise, yes. It is possible to use 2.4gHz 802.11 radios to go up to 30 miles legally, but why cant you modify your WaveLan/AirPort to go 30 miles? The reason is this:
Because the ISM band is a public-use band, The radio, the antenna, the cable, and the amplification equipment MUST ALL BE CERTIFIED BY THE FCC AS A SINGLE UNIT!!! This means, that if a particular high-gain antenna and/or amplifier is certified to be attached to the Apple AirPort (of which there are none except its internal antenna) then you may legally use it.
The WaveLan range extender is certified for use with the WaveLan equipment, but the apple airport is not a lucent WaveLan Silver in the eyes of the FCC. Thus the wavelan range extender is not certified for use on the airport -- which is what the first modification describes.
The second modification describes attaching 'standard' antennas to the AirPort by manufacturing a special cable that will let you attach to the special connector on the WaveLan card. I should note here that the reason there is a special connector on this card is so that only certified antennas may be connected to it without voiding its warranty and lucent/apple's responsibility for its performance! Am I beginning to make sense here?
The point is simple. When you open the AirPort or your WaveLan card and attach antennas or amplification that is not certified for use with the radio, you are breaking the law. Now, I personally don't really believe in the "certified as a unit" crap the FCC dishes out on public frequency equipment, but it is still the law.
Now, to raise another point.
11Mb radios are currently all DSSS. There aren't any frequency hopping 11Mb radios yet, although the 802.11 standard provides for them. The DSSS radios may use channels that are 2mHz apart, giving them a total of 11 usable channels in the 22MHz ISM band. The problem with this is that there are only 3 non-overlapping channels So to all of you out there who just think that you can extend your range all to hell and back, don't be suprised when four other people in your zip code do the same thing and find that none of you can even use your DSSS WLAN's!
Frequency hopping is another story altogether. FHSS 802.11 radios operate at up to 2Mb and you can co-locate 17 of these radios in one room and you won't interfere! If you want to be very cool to other WLAN users in your area, do check out FHSS radios, as they are much more practical for most WLAN applications. Honestly, if speed wasn't such a big deal to everyone and their dog then we might not even have 11Mb wireless until the Frequency hopping hardware catches up.
Please be responsible with your 802.11! If you don't, you're going to turn the wireless networking industry back to licensed microwave transmitters, and you'll probably just piss yourself off because all the public spectrum is gone.
~GoRK
Well actually, what you have just described is three (maybe four) seperate attacks. First, you need the ESSID to talk on the WLAN before you can even authenticate. The ESSID is not too difficult to discover if you have physical access to another piece of equipment on the network (especially with the apple stuff), but if you have to crack it, it's similar to a password attack. Then you need the WEP keys for auth. The WEP keys are usually password protected in the configuration software, so unless you desolder the EEPROM and read the contents out, you will have yet another password to crack. Finally, after you are authenticated with WEP then you will have to break the stream cypher. Oh, and by the way, it's 2^128 keys not 128^2. Your number of keys falls short by about 3.4 x 10^38. And brute-forcing WEP is going to be a pair of 56 bit keys if you have to do that. Needless to say, your'e going to spend quite a while breaking into this one. And this is why wireless is more secure than wireline, even without stream encryption. Funny how banks seem to get really paranoid when we tell them that stream crypto isnt really necessary on their wireless links when they aren't requiring wireline crypto on their leased lines. Of course, explaining the whole mess to them usually gets me a nice sale of some 3DES routers :)
I use an 8 port Cybex AutoView 200 with the built in second console port for a LongView reciever.
You can set up three tiers of 8 port cybex 200's to control up to 512 systems from one menu. Also, for remote administration, the 200 has support for one local console (plugged directly into the switch) and a second console up to 500 feet away over standard cat 5. The two consoles can control different systems independently or (this is cool --) the same system at the same time. The colors on the "remote" screen faded and stuff at first, but i ran some shielded cat5 with shielded ends and hooked the remote console up with a flat panel monitor and it is perfect 400 feet away.
~GoRK
Actually, I'm predicting that in 10 years the present designs for both PC's and mainframes will reach a bit of common ground to give us more functional scalable computing. The same components will make up both both consumer and enterprise computing hardware and the amount of computing power will be directly proportional to how much money someone decides to spend.
The current design of mainframes has many advantages that the PC can benefit from on a smaller scale - hardware virtalization, componentized architecture. Likewise, the PC has some advantages that the mainframe market is going to have to take heed of in the next 5 years or so in order to stay alive - real-time interactivity, extreme flexibility, and standards-based hardware design.
The key here is architecture interoperability, and I am simply predicting that within 10 years there will be no more bold dividing line between "PC" and "Mainframe."
Mainframes, from my understanding are built for:
1) Fault tolerance
2) Massive I/O
They accomplish this, generally, by a lot of virtualization in HARDWARE, while normal PC's do this virtualization in software using stupid tricks like time-sharing (and calling it multitasking)
The PC, though, is about to pull up its pants, so to speak. Crusoe is already virtualizing instruction sets of all the fanciest desktop processors. SMP is going to make a big leap when virtualization fully leaks into the desktop. This will probably happen inside of two and a half years.
Either way, I am projecting that the life of the mainframe is 10 years, maximum. Likewise, the paradigm of desktop computing as we know it is also going to be gone in this same span of time. Both will probably be replaced with some sort of scalable, componetized architecture that eliminates (or greatly reduces) obselescence, improves reliability, and increases performance.
Someone already mentioned Mac-On-Linux. There are a couple more Mac emu's for LinuxPPC in development, though. SheepShaver is working on a Linux/PPC port of their popular BeOS/PPC product. And ARDI has just released a version of their Executor product for Linux/PPC. Executor doesn't emulate PowerPC, but it does emulate a 68040 quite well, and it doesnt require Macintosh ROM's, a real Macintosh, or MacOS to run Mac software.
~GoRK
OK. Here's another take. Many newer games using 3D API's have to be written with resolution independence. For instance, on an old 3DFX Voodoo, you're not going to be able to push 30fps in the newest games unless you run at 640x480 or maybe 800x600. But on your brand spanking new GeForce 256 DDR you can do 1280x1024 at like 60 fps.
I don't really understand how everything under the hood works, but it appears to me that when a game needs to display 2D graphics, sprites, or entire 2D UI's, it makes calls to the 3D libraries, loading these graphics as textures that the accelerator can then scale, rotate, and all that other fun stuff. Load up Quake 3 and look at the main menu. The text is the same size no matter what resolution you're at and unless you're in some absurdedly high resolution, it doesn't pixelate, and the graphics card automatically anti-aliases the pixels.
Display Postscript, Display PDF, and other forthcoming display technologies rely a lot on software and still treat the computer display as a raster medium. These will be interim solutions, but if the proper hooks aren't put into these software components for hardware acceleration, things like Display PDF will overrun the processor at very very high resolutions.
How about this? Let's treat the video memory area in the graphics card as a canvas and draw vector graphics in it. These will naturally include bitmaps with physical size information, and even a legacy "raster canvas" mode to accomidate legacy applications. Then all that has to happen is the graphics card does the rasterizing to whatever absurd resolution you need and pipes it to the display.
A few things this implementation has the ability to do:
1) Support everything NOW. In legacy modes, you'd get anti-aliased scaling, much like when I change my resolution on this LCD monitor in front of me to 640x480. Sure, you wouldn't get the benifit of 200 ppi, but at least you would have a crisper screen to look at (one of the things that annoys me most about my flat panel is that you can see the individual Pixels and the grid in between them)
2) Take a lot of the graphics burden off of the CPU -- the performance increase from the modifications made to DirectX 7.0 to accomidate the GeForce and a "GPU" in general really beg for the same kind of GPU idea to migrate back to 2D, where it will be needed to support massive resolutions needed in the future. Gradients, scrolling, and moving entire solid windows and widgets around are some of the most CPU intensive operations that can be done (check your meter while running E with all the bells and whistles on!) This are things that should be done by the video card anyway. Let's see some people start putting hooks in there software and OS's to allow this! Stop thinking in pixels already!
3) Support legacy apps on new software/hardware in the future. Load a rater-drawn app into a texture buffer and a virtual "screen" that has pixel dimensions, then scale those pixels on the canvas appropriately.
So anyway, I guess we'll see now how this idea will hold up.
~GoRK
This is the German comment babelfished for other people like me who are interested.
My objection over LinuxONE LinuxONE had its saying, and this is meins. Which follows, a call is to the complaint on from us, which are interested -- large enough number for challenging vitriolic acceptance LinuxONE's over grade of transmission performance. I must protest to LinuxONE's use of bad Prudisharten to obtain its sadistic targets. This acknowledgment indeterminateness the demonstrability regarding an external to accompany objective reality is concerning a crisis our ability, to be known had that the only way, which is I LinuxONE perhaps forgive can, if it says the truth and forms returning. No matter how much discussion and analysis occur, an organization, which would like to receive in front, should tries, to understand the extensive consequences of its jokes. LinuxONE never had these training bodies. It always does, what would like to do and to figures it be able to do it at the moment to be situated even from all possible problems which develop. LinuxONE's cronies it seems to struggle that it cannot do injustice. I know, because I experienced that personally. LinuxONE's lackeys is frequently intercepted trying to stamp brutishwhinges. Of course they refuse this, but all we know full recess that LinuxONE is not capable to use the English language effectively or correctly. LinuxONE's maneuvers disbursed themselves: squalid wrongmoderated liars and cheat something success in their efforts, in everyone had to already interfere otherwise affairs. It is far away well-known that LinuxONE's philosophies are based on somewhat deep-rooted Funktionseigenschaftstoerung. But I have a tendency, over which more sensationalsachen the fact that LinuxONE to, is shocking the things, things to report as, like it would like to lead substantial documents hidden from the public, until they become politically contentious. And I carry out the difficulty, which has the average person when coming to the grasps with that, but it the case is literal, which we begin to witness the absorbed effects of its new interpretations of the historical cases. It is person suffering from a brain injury, so that LinuxONE regulates debt for social printing, economic loss, or loss of the political energy on a target group their debt designed, supplies a highly simplified assertion. Or possibly I should say, it am political false. If one needs a character the fact that LinuxONE is uncertain regards you that it forms a virtue of the not again-good-closing disturbance. Not too belabor the point, but LinuxONE states that its requirements are approximately hurt not worth receiving. I react that there is another page to the output. An old joke explains from the optimist up to now, which away from a building 60-story and, since it whizzes behind the 35th stick falls, " proclaims, so well! ", but such blind optimism, which henchmen LinuxONE's, is not over to think caused that they can animate a Arcadian behind that again existing ducks never. And that, in my opinion, is our real problem.
A Javascript OnMouseOver inside of an Anchor tag can change the apparent destintaion of a link by changing the text in the status window. So unless you like digging through the page's HTML and checking out the link you're clicking then this isn't really verifiably secure.
I for one think this is a stupid feature of javascript. I want the statusbar to tell me what the link is doing. A webpage shouldn't have the ability to screw with my browser's status bar! At least this should be a javascript option -- "Restrict Statusbar control" -- as other people have pointed out -- on and off aren't enough control!
~GoRK
How you people so quickly forget bringing about your own demise, and how quickly you defend companies who really aren't even your friend!
/. community would be the first people screaming against this sort of thing!
When Windows Media Player's streaming was first incarnated as Microsoft NetShow, MS worked with Xing to deliver players for damn near every single platform out there including Linux. In fact, I believe it was their second piece of software for Linux after the FrontPage extentions.
Now, we have everybody complaining about how MS is becoming more commonplace and RealPlayer is the only (large-market) solution still available under Linux.
Let me ask you this: have you ever tried to license a Real Media *SERVER* ? The licensing is absolutely ridiculous. Yes, I know they have the basic version but that's no good for any kind of commercial use. WMP's server-side application is included with IIS and has unlimited capacity. Hell, buying NT BackOffice (The entire operating system!) costs you half as much as supporting 100 streams of Real Media.
On top of that, WMP has better quality at the same bandwidth (at least for video). Just watch it or listen to it and it is not really a disputable argument. I'll give RealPlayer a chance too and say that it's more responsive when you want to skip around in a stream and it's way more fault tolerant.
Still, do you realize why you're complaining? You didnt support M$ tech when they tried to support *you*! I hate to have to defend them, but if the Linux/UNIX/Whatever people started driving and thriving in the streaming media market then we wouldnt look so second class to streaming media companies. M$ would probably still have a media player for Linux, and maybe some of their API's and CODECS would have opened up by now.
I am a bit annoyed with the defense of Real on this one. Getting the newest version of RealPlayer has always been delayed months (and close to 1 year on 5.0 and G2 -- they skipped 4.0 altogether), and until the release of at least 5.0 for Linux (which Real's web page makes nearly impossible to obtain) Real was an absolutely useless format if you wanted to do cross-platform video. Coupled with that, RealPlayer is a billion meg download that forces you to replace damn near every piece of multimedia software (at least on W32) -- I've stopped installing it on Windows. It absolutely is the most bloated, slow piece of garbage in the universe, and on top of that it (at least used to) gather up all of my personal info and beam it to RealNetworks!!
Please, stop supporting RealNetwork's trash! I would think that the
~GoRK
First off, this is the first time I've ever jumped into a GPL debate, so cut me some slack if I'm wrong about things.
OK, these are indeed Litestep *modules* are they not? I'm of the opinion that a closed source shell could include in its distribution one of these modules (as long as the interface that the module hooked to was developed independently, and could be put under a commercial license) As long as the author of the non-gpl application acknowledged the modules GPL status and distributed them with source, what would be wrong with the main appilcation even depending on these modules?
My reasoning comes from looking at something like perl. There are plenty of people out there selling perl programs under a commercial license. Many of these are not open source and are run through a code-scrambler and then sort of "linked into" a perl binary so they are standalone. Many of these programs use GPL'd perl modules and interfaces to many other closed and open-source applications. E.g. Tk, ImageMagick, GD on the free software side and things like Win32::GUI on the commercial side. As I understand it, the perl application can be licensed under any terms as long as accompanying software is acknowledged as being developed independently.
We just want to watch DVD's damn it!
Let's just for kicks say there is no deCSS and/or CSS wasn't feasably breakable. So I open up my DVD player and solder a few jumper wires from the data pins of the MPEG2 decoder chip, wire them up in some bizzare way to a computer, and press play. There we go. Decrypted DVD.
Look, MPAA. The assembly language code for deCSS is pretty much present in the BIOS or some other form of firmware inside of every DVD player ever made. Why don't you go sue every DVD player manufacturer? Why don't you go sue yourselves?
The normal transmission medium, however, is not where Tivo gets its program guide. The program guide gets downloaded via modem every three days or so along with the "Tivolution" digital magazine, software upgrades, and the like. The best part of this case is that even if the Tivo people have to change the device's operation somewhat to sidestep a bunch of bunk patents, they can!
I thought this article might be a good place to mention AT&T's DjVu image format. I have been working with their DjVu tools to develop quite a few web applications and they are phenominal. The format takes an image (it is designed for scanned documents) and creates an IW44 (wavlet compressed) background layer of the image and then creates a non-lossy overlay foreground layer to compress foreground components like text and lines.
The net result? 300 dpi full page scans in under 50K! When you print them, they are true enough to the original to justify the difference between a 5MB TIFF and the 50K DjVu.
I'm very glad to see some of the same technology being adopted into JPEG. I'm kind of dissapointed that the spec doesn't seem to allow the mixing of compression algorithm's inside of one image, which is what most all of the very very good compression methods seem to rely on -- the fact that different information in the same chunk of data can be optimally compressed in different ways. I mean, depending on the image, JPEG in some cases can smear wavlet-based methods into the dirt.
Just some food for thought...
~GoRK