Re: What is a parking garage?
In the US, parking garages are the same as UK carparks. They can be under the building (partially or entirely subterranean), adjacent to it, or completely standalone.
Posts by Justin S.
77 publicly visible posts • joined 14 Aug 2009
The choice: Pay BT megabucks, or do something a bit illegal. OK, that’s no choice
SpaceX says, sure, Starship blew up but you can forget about the rest of that lawsuit
Saturday 8th July 2023 08:55 GMT
Liquid oxygen doesn't start fires. It's an oxidizer, not a fuel. It will enable combustion if there's enough energy to start the process, but on its own it's simply cold. If something were on fire, or caused a spark, in the vicinity of the LOX tank when it was punctured, the added oxygen would have increased the combustion rate-- it would have burned hotter and burned out faster. Could that provide enough energy to start something else burning which normally wouldn't? Sure. What types of materials were in use at the tank farm? Concrete, steel, aluminum, copper, zinc, various types of polymers, and probably some paper. Anything else? Not in any significant quantity. The plastic and paper will combust regardless whether pure oxygen is present, but good luck getting the metals to burn-- it's possible under certain conditions, but not in the solid, bulk forms used at the launch site.
But let's entertain the proposition that everything at the launch site can be made to combust in a pure oxygen atmosphere:
A LOX tank is punctured, it begins venting, and something close and on fire begins to combust enthusiastically. This causes everything it touches to begin to burn. The fire spreads. But it only spreads as far as the venting oxygen allows, BECAUSE THE CONCRETE AND METALS CANNOT SELF-SUSTAIN COMBUSTION IN A NORMAL ATMOSPHERE. If they could, they would be unsuitable for use in pretty much anything. Need to cut a piece of steel with torch? If it were self-sustaining, the entire piece of metal would go up when the torch was applied. Same thing with aluminum, and just about every other commonly used metal. Pure oxygen in a kiln would cause the kiln to combust. Then the impossible, hypothetical launch site fire would burn itself out when the LOX tank ran dry. Even then, not all the oxygen would be used in combustion because the heat would cause it to transition to a gas and blow away.
But it's all a fantasy, because it can't happen.
And even if-- EVEN IF-- the impossible were to happen, it's difficult to be "terrified" of a LOX leak from five-plus miles away, which was the closest any person was allowed to be to the launch.
So rather than accuse me of "being a blind fanboy" and not "think[ing] about what [I'm] saying," perhaps you should stop being an ignorant, irrational alarmist about a subject you clearly know little about.
Saturday 8th July 2023 08:17 GMT
Re: cheers of Musk employees as they watched Starship break up in flight.
You consider beach sand to be a dangerous substance? Because so far, published tests on the "debris" which fell on Port Isabel have don't match concrete or Fondag, and the size and appearance of the bits of debris are consistent with sand (Dr. Phil Metzger, planetary scientist at the University of Central Florida, Jun 16, 2023: "Partial results on the analysis of the ejecta from the SpaceX Starship launch. The visible and infrared spectra of the fine particles that rained down on Port Isobel do not match the concrete or the Fondag that was picked up on the beach.").
The larger bits of debris-- the pieces which would have had dangerous momentum-- only made it one or two thousand feet from the launch site, which is well within the exclusion zone. If you know of larger pieces which made it outside the exclusion zone, please provide a reference.
As for damage, so far the only real damage reported is one or more broken windows, but that's literally all the news articles say: "[r]esidents of Port Isabel, a town six miles northwest of the launch site, told the New York Times that at least one window shattered," "[b]roken windows and ash-like particulate matter from the launch have been reported as far away as Port Isabel," and "media outlets reported shattered windows in homes in Port Isabel" are typical quotes. No interviews with people whose windows were broken, no specific locations where windows were broken, and no counts of windows which were broken.
But surprise, several quotes came from Dave Cortez, a leader of the local chapter of the Sierra Club, which opposed and continues to oppose Starship testing.
The reason you "don't know how much damage was done" is because there was no significant damage. If there were, it would be news-- if it bleeds, it leads, as the saying goes.
As for the FTS, you can argue that with the FAA if you'd like. They, as well as SpaceX, already know it didn't work as quickly as it should, and so SpaceX will redesign it. You say you want it tested? Well, to do that you need to launch a test article, so don't expect the FTS to prevent a second launch.
Friday 7th July 2023 18:23 GMT
More than that, the vertical tanks contained water, liquid nitrogen, and liquid oxygen, none of which are combustible. A LOX leak would only be a significant problem if something else nearby was on fire, in which case the fire would burn faster/hotter than normal. The methane is stored in horizontal tanks away from the vertical farm, behind protective berms, which was required by state law (and an example of existing regulation working as intended, since SpaceX *had* originally planned to store methane in the vertical tank farm).
Friday 7th July 2023 18:16 GMT
Re: cheers of Musk employees as they watched Starship break up in flight.
The launchpad did not fail "dangerously." Nobody would have been injured if the rocket RUD'ed the pad, and that's the only thing the FAA cares about-- they don't particularly care if SpaceX destroys their own facilities, only that they don't endanger people.
The FTS did work... eventually. Based on the videos, the rocket didn't break up from tumbling. In fact, the robustness of the rocket was likely contributory to the FTS not working as quickly as it should. This is the same FTS (or essentially so) as used on Falcon 9 launches, and that system *has* been tested in-flight, on the F-9R Dev-1 launch in 2014.
The solution to the SS/SH problem is likely to use a ribbon-style FTS instead of point-charges, which will cause part of the rocket to essentially "unzip." This will cause both catastrophic structural failure as well as rapid mixing of the propellants, increasing the likelihood of an explosion. Why didn't/don't they use a ribbon charge in the first place? Because no sane person wants to handle more explosive material than they have to, regardless whether it's considered "stable."
Hindsight is 20/20. They didn't expect the pad to crater like it did. I'm confident if they knew the pad wouldn't survive, they would have waited. But we don't know that the launch would have been "far more likely" to succeed, because we don't know the cause of the various failures. Did some engines fail due to FOD strikes? Almost certainly. Were ALL the engine failures due to FOD strikes, either directly or indirectly? We don't know. Were the explosions (engines or otherwise) which destroyed the TVC pumps caused by FOD strikes? We don't know. SpaceX might, but *we* do not.
Besides the delayed self-destruct, the loss of the TVC system was probably the most significant failure during launch. Fortunately, they're replacing the hydraulic system with electric motors, and they should be able to make the electric system much more robust to failure.
Friday 7th July 2023 17:15 GMT
Re: Space X
My understanding is that Boca Chica will not be for primary production, either: they are constructing several new buildings at their KSC facility on Roberts Road, which are expected to be manufacturing for Starship and Super Heavy (with engines built in Hawthorn, CA and McGregor, TX). I expect some production SS/SH rockets to be built at Boca Chica for the same reason I expect them to launch propellant fill missions from B.C.
Friday 7th July 2023 06:31 GMT
Re: "terrifying" sounds were reported in Port Isabel
Yes. They helped launch the most powerful rocket ever built, with the largest number of engines (though perhaps not, on the first try, the largest number of operational engines) ever flown. They knew and accepted the various degrees of "success" and "failure" that were possible and, getting as far as it did (and not completely destroying the launch site), they had a lot to be proud of.
Thursday 6th July 2023 22:49 GMT
Re: Space X
> "The site was a bit of a question mark when announced, as much of the content of the lawsuit was raised as issues at the time. TBH, I am rather surprised that there was eventual agreement amongst (collection of US Federal agencies with relevant oversite) and SpaceX that the site was usable for launching rockets without causing environmental chaos."
As improbable as it sounds, a wildlife preserve does not itself preclude successful, beneficial co-existence with a launch site. Kennedy Space Center is completely enclosed in the Merritt Island National Wildlife Refuge-- I encourage everyone to look at on a map, particularly the one provided by the U.S. Fish and Wildlife Service website. When I say "completely enclosed," I mean ***completely enclosed.*** There are bits which are excluded from the Refuge, but the Refuge runs right up to the edges of the launch pads and KSC runway.
And as bazza points out, there really aren't any locations along the Gulf or east coasts which could be considered 'unobjectionable' for development of a rocket as large as Starship/Super Heavy: it's all or almost all human inhabited or some kind of park or preserve. They could do more out of KSC, but only up to a point: KSC is used by more than just SpaceX, and NASA doesn't want their other operations to be unnecessarily impeded by the hardware-rich development of any of their partners/tenants. The same applies to Cape Canaveral Space Force Station.
But the Boca Chica site is not-- and may never be-- a "primary launch site." The recent FAA PEA specified limits on the number of launches SpaceX is permitted. These limits will mostly confine them to test launches, though I'm all but certain they will seek waivers if they get to the point where they're filling an orbital propellent depot to support the moon missions, because they and NASA will want to reduce the time between the first propellent launch and the trans-lunar injection burn.
Techie wasn't being paid, until he taught HR a lesson
BOFH: Ah. Company-branded merch. So much better than a bonus
Friday 12th May 2023 17:11 GMT
Re: When do people understand that cash rules?
Use aluminium wires with an iron oxide coating-- thermite cables, no additional oxygen required. Though I'm not sure the heat of the aluminium would be sufficient to start the reaction with the iron oxide, but the point stands: include the oxidizer in the cable.
Boss broke servers with a careless bit of keyboarding, leaving techies to sort it out late on a Sunday
Saturday 26th November 2022 14:57 GMT
Re: "an on-prem email server"
That and thermal management. What light isn't converted into electricity or reflected back into space is converted into heat, and that heat needs to be removed. In space, there is no convection or conduction to transfer/remove waste heat into the environment-- remember, space is vacuum, better than the gap between the inner and outer walls of your insulated flask/water bottle-- so you're left with radiation. Having the heat radiate into space is good, while having it radiate at the living quarters of the space station is bad-- they have enough problems getting rid of their own waste heat and don't need any from the solar array.
We've got a photocopier and it can copy anything
Sunday 24th July 2022 00:51 GMT
Re: Bank of England going to trade show
There was a story-- a decade or two ago-- about a guy who was briefly arrested for using $2 US notes at a store.
For those who aren't aware, there has been a $2 note in circulation for a couple centuries, but it's not widely circulated and is more of a novelty-- which is why this guy had them: he ran a program for kids, and as part of the program, he would give each of the kids a $2 note.
On the fateful day, he had a bunch of extra notes on him, and he needed to make a purchase. The cashier had never seen a $2 note before, thought it was counterfeit, and called the police. I don't remember if it was the cashier or police who noticed the note's ink would smudge while rubbed, but they did, they called in someone from the US Treasury, and brought it to their attention. The Treasury agent then told the police that the notes were real and that the ink would smudge.
Buying a USB adapter: Pennies. Knowing where to stick it: Priceless
File suffixes: Who needs them? Well, this guy did
BOFH: You drive me crazy... and I can't help myself
Tuesday 16th November 2021 22:06 GMT
Hydrofluoric acid -- there's a reason it's also known as "devil's p-ss".
As you say, concentrated sulfuric acid is a good option, but you really want to combine it with a strong oxidizer like hydrogen peroxide or potassium dichromate, as has been suggested by others, which will turn much of the carbon into carbon dioxide.
Scoot on over for a wheely tricky mystery with an electrifying solution
BOFH: Switch off the building? Great idea, Boss
The power of Bill compels you: A server room possessed by a Microsoft-hating, Linux-loving Demon
You *bang* will never *smash* humiliate me *whack* in front of *clang* the teen computer whizz *crunch* EVER AGAIN
Astroboffins may have raged at Elon's emissions staining the sky, but all those satellites will be more boon than bother
Not call, dude: UK govt says guaranteed surcharge-free EU roaming will end after Brexit transition period. Brits left at the mercy of networks
When is an electrical engineer not an engineer? When Arizona's state regulators decide to play word games
Wednesday 11th December 2019 16:48 GMT
Re: Rename the terms?
"High crimes and misdemeanors" means whatever the sitting Congress wants it to mean; the terms, as they relate to impeachment, are not defined in the US Constitution.
In theory, Congress could impeach the president 'because he looks funny,' though that would be a patently ridiculous thing to so, so it hasn't happened thus far-- we'll see if that changes after the next Democrat takes office.
With regards to the difference between misdemeanors and felonies in criminal law, their distinction is also up to the legislature (Federal, State, and local, and thus vary slightly between locales), but they generally refer to minor (public intoxication, disturbing the peace, and licencing violations) and serious (battery with serious injury, robbery or fraud in the thousands or more dollars, and murder) offences, respectively.
It's entirely possible, however, for the same crime to be a misdemeanor in one location but a felony in another. It's even possible to have a crime be both in one location, with the choice being up to the prosecutor. (These are called "wobblers," if you want to look them up.)
I don't have to save my work, it's in The Cloud. But Microsoft really must fix this files issue
A quick cup of coffee leaves production manager in fits and a cleaner in tears
Bad news for WannaCry slayer Marcus Hutchins: Judge rules being young, hungover, and in a strange land doesn't obviate evidence
Friday 15th February 2019 01:00 GMT
Re: Hutchins received notice of his Miranda rights?
Fun fact about Miranda: law enforcement only need to Mirandize you once you've been arrested. Technically, he was not under arrest for the first part of his interview-- even though they had a warrant to arrest him. It's a technicality-- and a crappy one at that-- but it follows the letter of the law and has been allowed by the courts.
Edit to add: I should also clarify that-- contrary to television and the movies-- the police don't even have to Mirandize you at arrest; it's only necessary if they ask you questions. So if you're nicked for public drunkenness and start blabbing on the way to the local jail, that's on you. If, however, the police ask you questions-- where were you, who were you with, whose drugs are these-- without Mirandizing you, your attorney has a good chance of having your statements excluded from evidence.
So, when someone from law enforcement starts asking you questions: shut up. Don't try to be helpful, because you don't know if you are-- or will become-- a target of their inquiries. And for God's sake, don't discuss anything you know or suspect might be illegal with *anyone*, whether they've identified themselves as law enforcement or not.
Latest Google+ flaw leads Chocolate Factory to shut down site early
On the seventh anniversary of Steve Jobs' death, we give you 7 times he served humanity and acted as an example to others
What do a meth, coke, molly, heroin stash and Vegas allegedly have in common? Broadcom cofounder Henry Nicolas
Tired sysadmin plugged cable into wrong port, unleashed a 'virus'
Monday 9th July 2018 10:21 GMT
10 minutes is 9 min 58 sec too long
Once upon a time, I crashed a Cisco 6509 core switch by connecting a new, yet-to-be-configured Netscreen firewall into it-- trust and untrust ports both. I hadn't realized that model firewall shipped in "transparent" mode, so it formed a loop on the switch.
I plugged the second interface in and, maybe two seconds later, every port indicator on the 6509 went dark and I heard some relays tick-over. Portfast was enabled on the switch ports.
After disconnecting the untrust port and configuring the firewall for NAT/routed mode, I was able to reconnect the untrust port without the switch falling over, so it wasn't electrical.
It probably didn't crash from the storm, either, but from a bug in the firmware-- I can't imagine a multi-gigabit, enterprise switch crashing from a measly 100 Mbps loop, but that's what happened.
Ex-Rolls-Royce engineer nicked on suspicion of giving F-35 info to China
Thursday 14th June 2018 15:44 GMT
Re: Stupid... Just stupid...
The Space Shuttle-- at least near the end of the program, if not from the inception-- had the capability of automatic landings, but it was never used due to the culture at NASA that a human should always be in control of the craft. That culture originated with the early space program, when the recruited pilots objected to being mere passengers.
www.spaceref.com/news/viewsr.html?pid=10518
Pharma bro Martin Shkreli to miss 2024 Paris Olympics
Saturday 10th March 2018 06:26 GMT
Re: is that including time served
The seven year sentence does not include time served, which is six months at present, bringing his total sentence to 6.5 years. Unlike state prisons, the federal prison system does not offer parole or probation, so he'll serve almost all of that, minus up to 54 days per year for "good behaviour," so he could reduce that to a little more than 5.5 years.
Thought your divorce was ugly? Bloke sues wife for wiretapping – 'cos she read his email
Thursday 3rd August 2017 06:26 GMT
Re: Why issue a sueball?
I wonder how much discretion the police get, or if they have a huge backlog of super-serious crimes to prosecute.
Contrary to popular belief, the police in the United States don't charge or prosecute people. They collect evidence and they arrest people-- ideally people under reasonable suspicion of committing a crime, but regrettably that's not always the case.
The decision to file charges/prosecute a person rests with the District or State Attorney's office. There's no national standard or requirement that I know of, but generally the prosecutor's office has two or three days to file charges after an arrest, otherwise they are required to release the arrestee; in California, they have forty-eight hours.
It is not uncommon for someone to be arrested and then released without charge: because an honest mistake was made by the arresting officer; because the prosecutor's office decides there isn't enough evidence; or because the officer acted stupidly or maliciously.
My guess for this case is that the police and/or District Attorney's office don't want to get involved, probably because it's almost entirely a domestic dispute.
If the plaintiff manages to win the case, his attorney might hand the evidence collected to that point to the District Attorney's office, which might be enough to get them going, and he would probably file a bar complaint against the ex-wife's divorce attorney.
Shock: NASA denies secret child sex slave cannibal colony on Mars
Waymo: We've got a hot smoking gun in Uber 'tech theft' brouhaha
Sunday 25th June 2017 19:46 GMT
Re: Hiring from the competiton - unprecedented?
The events unfolding between Waymo, Uber, and Otto aren't unprecedented, but it's not just "hiring from the competition," either: this is a case of employees (plural) going rogue, stealing from their former employer, and selling to an unscrupulous competitor.
Look at the timeline (condensed):
* Dec 2015-Jan 2016: Levandowski downloads thousands of files from Waymo's servers, and (unsuccessfully) attempts to cover his tracks. During this time, he and another Waymo employee (Ron Lior) solicit other employees to jump-ship.
* Jan 2016: Levandowski and Lior resign, form 280 Systems (which will become Otto), and meet with Uber execs. Uber awards Levandowski 5.3 million shares of Uber stock, which begin vesting the day after he leaves Waymo.
* Feb 2016: Levandowski and Lior officially form Otto. They sign various agreements with Uber, and Uber and Otto begin the process for Uber to acquire Otto.
* July 2016: Multiple employees leave Waymo for Otto. Some downloaded more documents on their way out.
* Aug: 2016: Uber announces its acquisition of Otto.
There were some other shenanigans in there, involving companies called Odin Wave and Tyto Lidar. Odin Wave's registered address was a property owned by Levandowski. A manager at Tyto Lidar is a friend of Levandowski. The two companies merged, were acquired by Otto, and then Uber.
From an article at Axios, "In 2013, [Odin Wave] reportedly ordered a custom part from a vendor used by Google that was very similar to Google's. Google employees questioned Levandowski but he denied any involvement with the company."
There's a comprehensive timeline at axios.com, which includes links to supporting documents (legal filings and other news articles): https://www.axios.com/the-tortured-history-of-the-uber-waymo-legal-fight-all-in-one-place-2349566425.html
Ex-Waymo engineer pleads the 5th in ongoing Uber law fight
What's got a vast attack surface and runs on Linux? Windows Defender, of course
Wednesday 24th May 2017 04:58 GMT
Re: But isn't the environment itself just as important?
@ShelLuser
If you don't have access to the source code, you're left with either decompiling the software and/or running it in a debugger, laboriously reverse-engineering the software to see how it works and might be broken. That is a far slower process than running automated throw-it-at-the-wall-and-see-what-sticks sessions, and then checking out the interesting results.
Tesla sues ex-manager 'for stealing 100GBs of Autopilot secrets'
Aaarrgh, zombie! Dead Apple iOS monopoly lawsuit is reanimated
Saturday 14th January 2017 01:09 GMT
Re: Who is paying these corrupted judges, uh?
'What's a relevant market? It is a market category, like "mobile phones" or "smartphones". It is NEVER "product x from a single company" unless there are no comparable products available from other companies'
Incorrect. Apple-- among others-- sold personal computers during the mid- to late-90s, at the same time Microsoft was in its prime. That didn't stop the Department of Justice from filing an antitrust suit against Microsoft in the mid 90s, and then again in the late 90s.
The complaint filed by the DoJ in the latter case specifically referenced "Intel-based" personal computers, and specifically stated the monopoly position existed for them. From the complaint: "The market for personal computer operating systems consists of operating systems written for the Intel x86/Pentium (or 'PC') class of microprocessors... Thus, OEMs and PC users do not consider an operating system that runs a non-Intel-based personal computer to be an effective substitute for an operating system that runs an Intel-based personal computer... And because there is no viable competitive alternative to the Windows operating system for Intel-based computers, OEMs consider it a commercial necessity to preinstall Windows on nearly all of their PCs." (See also: https://www.justice.gov/atr/complaint-us-v-microsoft-corp)
In the current instance, Apple manufacturers the hardware and operating system, but they do not write all the software, leaving that up to third-party developers. No third-party can make an Apple-compatible device (legally), and only through Apple can third-party software be sold.
This is different from Android-compatible applications, which can be run on devices from many different manufactures, and sometimes on devices that do not claim compatibility-- like Amazon devices, which are based on the Android OS, but which are not really, legally Android.
The market for Apple devices is smaller than Android overall (according to IDC), but is nonetheless substantial, and companies frequently write software for both so as not to miss profiting from each ecosystem's substantial user-base.
If the EC can make an argument for Google-- which gives away Android for 'free'-- being a monopolist in the Android ecosystem, where does that leave Apple and its iron-fisted control over the Apple ecosystem?
Saturday 14th January 2017 00:28 GMT
Re: How were they not customers?
"Anyway, the fact Google takes the same 30% means any attempts to claim that 30% is excessive are unlikely to succeed."
Maybe, maybe not. Unlike Apple, Google allows third-party app stores (e.g. Amazon's app store, etc; search "third party android app stores" for a large list of potentially dodgy options), and therefore is not a monopolist for app stores on the Android platform.
Binary star bash-up should add new light to Northern Cross in 2022
Wednesday 11th January 2017 06:45 GMT
Here's hoping for something funny happening...
“If we’re right it would mean the science is already done,” he explained. “What’s exciting is what we don’t know.”
'The most exciting phrase to hear in science, the one that heralds new discoveries, is not “Eureka!” (I found it!) but “That’s funny …”'
— Isaac Asimov (ascribed)
Weather stops SpaceX from blowing up more satellites
Tuesday 10th January 2017 00:08 GMT
Re: Flight failures
@ Bubba Von Braun
"Does not include development flights/failures as Atlas/Thor/Delta/Taurus failures are not available, so I excluded the Falcon 1 stats for balance."
And then you include a crap-ton of development flights for Falcon, e.g. anything listed as "Grasshopper" ("...consists of the first stage of Falcon-9 v1.0, fitted with only one Merlin-1D engine and fixed landing legs"), "Falcon-9R-Dev-1" ("...is test vehicle for the Falcon-9 v1.1 and consists of the longer first stage of Falcon-9 v1.1(ex), fitted with three Merlin-1D engine and operational deployable lightweight landing legs"), and/or "(R&D)".
British military laser death ray cannon contract still awarded, MoD confirms
Programmer finds way to liberate ransomware'd Google Smart TVs
Russian banks floored by withering DDoS attacks
Friday 11th November 2016 20:13 GMT
Re: The problem is the internet protocols - Explain!
There are many network protocols, and they exist in a hierarchy (I'm referring to the OSI model here; other models exist).
OSI layer 3, the Network layer, is "IP" or "Internet Protocol." Its job is to facilitate moving packets of data from one host to another, locally or across routers. While it is responsible for moving data between hosts, it cannot deliver it to the applications or services that need it-- that is done by OSI layer 4.
OSI layer 4, the Transport layer, is responsible for the end-to-end delivery of data for applications and services. There are two main Transport layer protocols for use with IP: "Transmission Control Protocol" or "TCP"; and "User Datagram Protocol" or "UDP."
You might recognize TCP from "TCP/IP," which commonly-- and improperly-- is used as shorthand for any Internet data communication. TCP is a "session oriented" protocol. That is, communication using TCP requires that the client and server establish a session before communication commences, which requires the client ask the server to start a new session, receive an acknowledgement from the server, and then negotiate the session details.
Setting up the session is, relatively, expensive: it take a bit of time, because multiple non-data exchanges need to occur first, and it requires a little more RAM to maintain information about the session. TCP has its benefits, however, because it guarantees the delivery of data by ensuring each packet is received and re-sending those that go missing. It also requires that the client address in the IP header be valid, because two-way communication is necessary to complete session setup. Most protocols make use of TCP: HTTP, SMTP, POP3, IMAP, SSH, TELNET, FTP, LDAP, SQL (Microsoft, MySQL, Postgress, Oracle, etc), and so on.
The other Transport layer protocol, UDP, is "the" problem. UDP is a "connection-less" protocol, which does not require any session setup. A client simply sends a UDP packet to a server and the server-- if it is listening-- sends a response. Because there is no session information, there is no built-in retransmission of lost packets, but that's usually okay because you rarely use UDP for anything sensitive to data loss: audio and video transmission are the most popular uses of UDP, along with DNS and NTP. It also doesn't perform any validation of the client address in the IP header.
The lack of session setup makes UDP ripe for abuse. A malicious user can create a UDP packet to a server with the "from" address field set to the target system the user wants to DDoS, "spoofing" the address. The server, upon receiving it, will then reply-- completely unaware that it is sending to a third-party.
UDP attacks are made worse by a process called "amplification." Take DNS, for example: the spoofed DNS request doesn't have to be very large-- maybe 120 bytes, maybe less-- requesting a particular domain name lookup, but the lookup could be for a domain name with lots of records, causing the reply to be ten or more times larger. This amplifies the attacker's power, allowing him to generate ten or more times as much traffic as he has directly available through his Internet connection.
Taking over an IoT device is even worse, as the attacker now has the potential to load custom scripts or firmware and generate attack traffic directly, without relying on amplification and with minimal Command and Control traffic. And because the traffic is sent using UDP, there's no session setup to prevent or mitigate the flood: it just goes and goes and goes.
It should be noted that TCP is not without its faults with regard to DoS attacks. One of the early DoS attacks involved sending bad session setup requests that were never completed but still caused the server to allocate resources while waiting for the session setup to complete, which ultimately lead to resource exhaustion and the denial of service. This has been at least partly mitigated, and tends to affect a small number of servers, so it is no longer a common attack method.
UDP attacks, on the other hand, are kind of like saturation bombardment: the target server is knocked out, and service is degraded or denied for anyone else using the same Internet connection as the target.
Elon Musk: I'm gonna turn Mars into a $10bn death-dealing interplanetary gas station
Wednesday 28th September 2016 00:40 GMT
Death and taxes
> SpaceX founder Elon Musk has laid out an audacious multibillion-dollar plan to send colonists to probably die on Mars.
Well, yes, they're colonists. Whether they die on their second day or forty years later, after having children and grandchildren, they probably will die on Mars.
Biting the hand that feeds IT
