ZScaler mention that they will be releasing another blog about the effect of ESNI on their system.
It will be interesting to see what they say.
907 posts • joined 4 Feb 2008
The massive hiring spree was followed by a somewhat less massive firing spree, in certain areas of the company. I know a fair few people who thought they were on to a good thing but were shown the door because ARM hadn't realised that they were actually cannibalising their customers' own business models.
If only Mr Marlinspike would also take notice of the vulnerability of centralised infrastructure too, he's stated quite clearly that he doesn't want to give up control of the server side stuff by migrating to distributed infrastructure. It may complicate things, but it would be more resilient and essentially immune to government action.
This problem originated with a heated oxygen tank that wouldn't drain its liquid contents which was worked round by boiling it off, this process itself leading to the fused thermostat where the gauge that could have revealed the consequent overheating was unable to display a measurement above 80F because that was assumed to be covered by the (failed) thermostat action.
They were really lucky that the centre engine on the SII stage didn't fail under pogo oscillation, it only shut down because the 62g vibration made the thrust sensors indicate low thrust and the control system think that the engine had exhausted its fuel. 1 more second and the whole remaining stack would have broken up.
In the current world situation I imagine it won't be long before a goodly percentage of 787s are simply powered down somewhere out the way and left until there are lemon-soaked paper napkins again.
Of course, it might give RR a chance to catch up with engine rebuilds that have left some aircraft on the ground for a fair while in any case.
If it's Boeing, I'm not going.
During the Apollo 13 mission, a failure was avoided by the skin of NASA's teeth when a vibration of >62g occurred in the centre J-2 engine on the SII stage, the engine and mount moved a good 6" or more in the longitudinal plane before a shut-down was triggered probably because the thrust sensors thought the increasing rearward movement indicated loss of thrust. Had this not happened there was only a second or so before a total structural failure and almost certainly loss of mission and crew.
This was recognised and fixed before Apollo 14 launched.
The reason that the Rockwell B-1B is generally subsonic, or at least not Mach 2 capable, is because the US couldn't get the original intake to work properly. They did ask for help from Ted Talbot who got the Concorde inlet to work, he said he thought that it would prove impossible because whereas a Concorde intake was only angled from top to bottom the B-1A intake was raked in 2 directions, top to bottom and side to side, making the control mechanism to keep the shockwave focused on the inlet lip too difficult for the computing power of the day.
Leaking HTP tank in a large exercise torpedo without a warhead, started decomposing inside a closed torpedo tube, blew open the inner door and then after a few minutes of heating everything in the torpedo room to a couple of thousand degrees C with the torpedo fuel there was a multiple armed torpedo warhead detonation that blew a hole in the hull and sank the sub.
Not recommended at all.
You know you're in trouble when you have to measure the warming of your oceans using zettajoules as units. Not to mention having probes that are sampling single measurements in areas of ocean roughly the size of Portugal and you don't actually have full coverage of the oceans.
Science? We've heard of it...
Well, yes, but this problem was essentially down to software.
The initial lightning strikes on the Barford-Little Wymondley transmission line caused a trip, these systems reset and were back on line in about 20 seconds and all should then have been well. However, the Hornsea wind farm's connector saw microsecond transients caused by the initial trip and reset, threw its toys out of the pram, and sulked. Little Barford went off line in various stages, and the 1.8GW of generation capacity that tripped out in total then caused the final load shed to prevent catastrophic frequency drops in the whole grid.
Hornsea have re-configured their system to be less pernickety, Newcastle Airport realised that they were not a protected customer and quickly asked to be so on the Monday after this happened.
Old-fashioned steam age electrical stuff is quite happy with things that take a few seconds to stabilise, clever fast sampling new wonderful stuff needs analogue and digital filtering to take account of transients, and people that can count to type in the correct limit frequencies in the traction control systems.
Apollo 13 almost had a fatal failure during the second stage burn, the centre engine suffered a pogo vibration that caused the engine mounts to move nearly 6 inches at the peak of the cycle. Had this continued another cycle or two the stage would have come apart but luckily the sensors detected problems with fuel pressure and shut the engine down.
Jim Lovell thought that this was the mission's glitch and that they wouldn't have any more problems, but he was wrong on that count.
The crash was essentially due to additional factors, one being that they descended to 30ft over a runway that they could not land on when they were supposed to fly past at a minimum of 100ft if this was the case. This affected the flight control systems, disabling some of the protections that are inhibited if you are intending to land.
When they realised that they were too low and selected takeoff/go-around thrust, the spool up time of the engines was about 7 seconds, by the time the engines had increased thrust from near idle power they were busily ingesting tree branches and naturally flamed out as the combustion chambers filled up with crushed wood.
The A320 was very new then, and a lot more is known about the Airbus flight control systems now. The aircraft did what it was told to do, the flight crew were just a little bit ignorant about the corner case they were exploring.
This was exactly the reason that Ionica's Fixed Wireless Access phone services at 3.4GHz stumbled, the original channel sounding didn't spot the short delay multipath from trees and similar stuff and so the equaliser in the modem couldn't deal with it.
Of course, their bigger problem was installing many CP devices in premises where the customers wouldn't pay, but halving their premises per base station with DSP limitations and then halving maximum range due to the multipath problem didn't help with roll out.
Wasn't the 1990s fun in telecoms?
Once upon a time we used to actually make complex devices and do difficult engineering in the UK, but in so many areas of that large sector we lost our way. The UK is the only nation that built a capability to put satellites in orbit and then abandoned it.
Building our own GNSS system would be an excellent idea, even better would be building the launch vehicles to send the space-based part of such a system into space. We could probably even teach people educated in the UK to design these systems and learn how to engineer complex systems again as a national capability.
I find it hard to understand how we got to be where we are now, the sooner we start to build our capabilities again the less we will hear about how difficult it will be when we are no longer in the EU.
They eventually developed them to the point where nothing physically cracked during the necessary burn time. But I do recall a Vulcain nozzle distorting and causing the changed thrust axis to push the Ariane off course and it failed to reach orbit.
When the Russians were developing the oxygen-rich turbo-pump-exhaust closed-cycle engines they had a few failures. Apparently when they went wrong the several inch thick steel turbo pump casings burned through in a few hundred milliseconds.
Sadly previous experience is that the public sector tends to be even worse at this than a private company because the investment rules are even more strict and the people running the show are not from the top of the barrel.
I don't really know the answer, but making it compulsory to put in FTTP cabling on new build and renovated property would be a good move wouldn't it? The complaint from Openreach et al is that the costs are heavily loaded towards the last mile, shared infrastructure is cheaper so if the last mile stuff is already there then the process is less capital-intensive.
ThrustSSC used rear-wheel steering for aerodynamic reasons, it worked but it caused a few problems. Andy Green had to drive while inputting two different steering movement frequencies (fast and slow) and also deal with the need to steer in reverse to begin a correction and then reverse the input again.
Andy Green is quite simply an amazing bloke, naturally he has the ability to think ahead of the car because that's what flying fast jets does for you.
Thrust 2 reached a peak speed of slightly under 651mph, as you say the CFD predicted that the car would have flipped if it had gone 6mph faster which is lucky because before the record run they had cranked up the front suspension by literally thousandths of an inch to get a higher peak speed.
ThrustSSC learned from this, they had a Martin-Baker rocket pack installed inverted ahead of the cockpit. If the front wheel loads had dropped below a pre-set value then the rockets would have fired to use 4,000lb of thrust to keep the nose down, followed by jacking up the tail suspension and releasing the brake parachutes to abort the run. When you hear the "armed" and "safe" calls on the radio these refer to the arming switch for the abort system which includes the rocket pack.
ThrustSSC created a shockwave that pulverised the surface of the Black Rock desert in Nevada, it was one of the reasons why they stopped after getting past Mach 1, the wheels were rotating much more slowly than they should have been and the structure of the car was being pounded by the supersonic flow and the acoustic energy from the RR Speys at close range. Some of the team wanted to put in the more powerful Spey 205 engines but it was decided that the risks were getting larger and it didn't make sense to ruin the very good safety record that had been built up.
BloodhoundSSC is a much different design, whereas ThrustSSC had a flat bottom across quite a broad part of the fuselage the newer car has less of itself close to the ground giving more space for the shockwaves to dissipate.
The B-1A was cancelled because they couldn't make the engine air intakes work properly whereas the Concorde intakes did all that was asked of them.
The B-1A intakes were swept in two axes, Concorde's were swept in only one axis. The additional axis on the B-1 made it impossible to control the shock waves at high speed, that's why the B-1B was limited to about Mach 1.25 (they also took the opportunity to add RAM baffles to reduce radar signature from the compressor face).
Ted Talbot, the man who ran the Concorde air intake design team was shown the B-1A in 1975, he looked at it, noted the large number of pressure-measuring probes around the inlet and correctly predicted that it wouldn't be made to work with the technology of the day. Even the Concorde inlet was right at the limit of what could be done with 1960s/70s technology.
And yes, SR-71 inlets operated at Mach 3+. But they are symmetrical and circular, removing quite a lot of the difficulties...
Because he wanted one, and it's his money not mine. He previously had an iPhone 4S and then an iPhone 6 so he's replaced each phone after a couple of years. By the 2 year mark the screens are usually cracked, I am hoping that he manages to look after this one better with the assistance of a decent Spigen case.
I happened to charge, boot up and update my daughter's Z10 BB10 phone the other evening.
After almost 18 months it didn't actually feel slow or dated, and the hardware was as tank-like as ever.
But the is no question that things have moved on, my daughter is now using Android and my son had a new iPhone 7 delivered today. There are not going to be many competitors to these two platforms now until a new generation emerges whenever that will be.
It's certainly worth trying but remember that the Snapdragon 800 is a 32-bit ARM v7 chip and also that Qualcomm does reduce support for re-writing drivers for the low level stuff in the chips so that they can concentrate on current and upcoming designs.
Android 7 is certain to make more use of the efficiency of the 64 bit v8 cores and is bound to work better with more RAM. I have a Nexus 5X that is running Nougat as of last night, it will be instructive to see how the 2GB RAM affects it, during the Lollipop and Marshmallow era it felt sluggish at times but has been massively better since the system interrupt rate was increased a few months ago.
...but I do wonder why the A600 had been painted with double-yellow lines outside the sheds (derestricted, fairly narrow, blind bends) and then people were allowed to park on the lines both sides and create a traffic nightmare. With hundreds of pedestrians around there too it was just asking for trouble.
I wish HAV well, but someone needs to think about what to do with the spectators.
...that the technology that prevents access to organised criminal communications is the exact same thing that prevents access to government employees acting as whistle-blowers about abuse of legal restraints on law enforcement and intelligence agencies.
Apple quite understands that there is a moral issue, but cannot act if providing access allows government to cover up good things instead of simply prosecute bad things.
Ethical dilemmas are not easy to resolve.
It was a fairly pointless safety measure too, the weapon had a cadmium safety wire which was inserted into the stationary part of the warhead but if surrounded by water there was enough uranium 235 to reach critical mass. Had the aircraft gone into the water if it couldn't maintain altitude it is quite likely that a low-yield nuclear explosion would have occurred.
The Little Boy design fired a hollow piece of U235 onto a solid cylinder containing more U235, because there was essentially no compression the design relied on very large amounts of fissile material. It was a stopgap weapon and there was no intention to build more than one, although in fact more were built because of the need to prevent the Hanford reactors being damaged by the Wigner effect (stressing the reactor cores due to unexpected nuclear reactions).
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