Posts by Martin Gregorie 1346 publicly visible posts • joined 10 Apr 2007
Plutonium dioxide and batteries - the same system that Curiosity uses.
The lump of plutonium dioxide generated 110 watts at launch, so slightly less by now. The batteries are needed to store enough energy for processes that need more than 110 watts, e.g. driving the rover or running MOXIE and PIXL.
(Slightly) more detail here: https://mars.nasa.gov/mars2020/spacecraft/rover/electrical-power/
Just how much progress has been made in recovering those 400,000 mugshots and fingerprints that got fat-fingered off the Police Database?
Its about time we had a progress report on that. I know the answer is probably "no comment", but all the same an official progress report to confirm or deny what we all expect would be nice.
Thats what ODBC helps with and JDBC fixes almost entirely, because both generally return columns in the programming language's nearest match to a particular column's data type.
Of course, if the database was "designed" by the sort of numpty who thinks integer values should be stored as character strings, then all you can do is light the blue touch paper and run.
Experience as a sometime DBA stongly suggests that a major source of poor RDBMS performance is that the system designers have no idea of which queries will be the most frequently used and that this information is seldom available to the DBA. This isn't really their fault since very often the system's sponsors and future users don't know this either. The result is that all too often a well-designed RDBMS schema generates a database that runs like a lobotomised snail.
Very often its performance can be hugely improved by merely adding indexes that actually support the queries that the application's logic needs to do its designed task and.or reorder the columns within indexes so the queries return rows in the required sequence without needing to sort then as they are extracted from the database.
Its quite remarkable how much a star schema can be sped up by merely reordering columns in the prime indexes and, of course, this sort of fix doesn't require any of the SQL queries or the code calling them to be rewritten.
Whats needed to improve the average RDBMS performance or maintainability is not a sexy new way of writing queries: instead all that's needed is an SQL interface with an EXPLAIN capability to analyse how any given query will interact with the RDBMS content, structure and query mix plus a DBA who is well enough trained to use the EXPLAIN output to better match the database's physical structure to the queries executed against it.
I agree with the general view that all elements of the financial sector must play by a common set of rules, but disagree that payment services should be treated like banks, because they aren't banks: they don't hold monetary amounts except for the short time they are in transit through the payment system, don't pay interest or service debt.
The better model to follow is that of existing funds transfer services, e.g S.W.I.F.T. and SEPA internationally, or CHAPS, FASTPAY and BACS in the UK, which are all designed to securely handle financial transfers between accounts at any pair of member banks.
Yep, I got pissed off by the monkeying with /etc/resolve.conf too, mainly because for years I've just slapped a local customised copy over the top of it whenever a system upgrade caused name resolution to fail. This time, after a couple of reboots I finally read the version that got pasted back in place at each boot, did what it said and have decided that I actually quite like putting all resolver customisation in /etc/systemd/resolved.conf because it does at least collect a number of related settings in one file.
Still somewhat annoyed that somebody thought it would be a good idea to put these hints in the replacement /etc/resolve.conf rather than an easily found manpage, though.
ymmv, but in my experience awk kicks the crap out of other programs designed to do the same job. The only one I think comes near it is NCC Filetab, which was around on ICL kit around 1970 and is still available for Linux and Windows.
Where awk is regex based, filetab uses a decision table to specify the data selection and manipulation you want.
I've used and dislike one or two other pretenders for this task space (RPG3 and sed): neither can match awk for ease of use and readability.
Same here. I've been using Redhat Linux since version 6.2 and Fedora since it first appeared.
I wasn't happy with Gnome 2's half-finished release and then, still unfinished, its abandonment in favour of Gnome 3, which I hated on sight. At that point I switched to XFCE and have been there ever since. Why not? It does what I want and doesn't annoy me with excessive decoration and fiddly bits.
It didn't look at all like that when I was driving round the Olympic Peninsula in the early '90s. Just vast areas with 2-3 metre high stumps where big trees had been lopped off and carted away with little concern for making use of as much of the wood as possible. What regrowth was visible was obviously natural regrowth and owed nothing to any sort of planned replanting.
No need for a big water bath - just send space walkers out to spray the outside of ZVEZDA module with a latex-based coating then do another spacewalk a few days later to spot the bubble(s). Just be careful to mask off the viewports before spraying the module if you'd like a nice, clear outside view after the leaks have been found.
This approach should suit the Russians just fine - they like simple, robust solutions to problems. For confirmation of this, check out the story of the Salyut 7 revival after it lost attitude control and all solar power. The full story is here:
http://arstechnica.com/science/2014/09/the-little-known-soviet-mission-to-rescue-a-dead-space-station/
In the companies and on the projects I've been involved with, talk about master/slave relationships have been very few and far between.
In describing an unequal relationship, its been far more common, in the placed I've worked, to describe it as a client/server relationship, which in fact describes the situation a lot better since the end with multiple links, the server, is much more likely to be responding to requests from its many clients than the other way round.
A new hardware and OS architecture bearing a strange resemblance to the hardware rings of protection used by operating systems like ICL's VME/B (and possibly also the Burroughs B-series and IBM/s progressively renamed Future Series->System/38->AS/400->I-Series hardware) could be as good as way as any of preventing this sort of cross-process data-stealing bug.
I've designed systems and written code for VME/B systems and never heard even a rumour of process-process interference occurring. Same for the AS/400.
If the GPS blocker is a ground installation, good, old fashioned inertial navigation should do fine provided that the warhead's destructive radius is about the same size as the inertial navigation system's error circle.
If the blocker is being carried by a drone, then IR terminal guidance should do nicely.
... because, quite apart from the effect on astronomy and, eventually, on other launches, they are incredibly wasteful of resources.
Think about it: an LEO satellite has a lifetime of around a year, after which it burns up in the atmosphere and must be replaced. The materials used to make the satellite and its electronics, some of which are quite rare while even the copper and gold used for PCBs and contacts are not exactly common, are completely lost since, on re-entry, the entire thing is reduced to tiny, unrecoverable pieces in the upper atmosphere.
By comparison, the unthinking fat cat who, 'because he can', buys a new iPhone every year and landfills the old one is a paragon of materials thrift. Why? Because the location of landfill sites are known. They can, and will be, mined for their more valuable content. This will be recovered and reused: a landfill could easily have a higher concentration of the many of the commercially useful rare elements than the mines they are currently extracted from.
This rant was inspired by today's 'Life Scientific' on Radio 4 - an interview with Sarah Bridle, a data scientist who has found the skills she developed searching for dark matter and dark energy are equally useful for dealing with the effect of food production on global warming. Its available from BBC Sounds and is worthwhile listening to.
The AAIB report is here:
https://www.gov.uk/aaib-reports/aaib-investigation-to-alauda-airspeeder-mk-ii-uas-registration-n-slash-a-040719
Very long, but very complete and well worth reading. As usual, the AAIB did an excellent job of analysing the crash and what caused it.
Neither the CAA nor the CASA (Aussy CAA) exactly cover themselves with glory over this, while the Alauda gang, who 'built' this chunk of junk just come across as a bunch of incompetent fuckwits.
How can hackers in North Korea manage to extract large amounts of cash from ATMs in Pakistan without help from a gang of locals to do the leg work and pick up the bills as they are spat out?
Assuming Pakistani ATMs are similar to others on the subcontinent, they'll be good for accepting and dispensing cash, and maybe showing your bank balance, but that's all they can do.
Other stuff, like SWIFT gateway hacks, can can obviously be done remotely, but ATMs? C'mon.
Every technical or biological mitigation will fail without a meaningful reduction in the human population, and I agree that a 2 child limit is the fairest solution provided its fully and fairly enforced and that reliable contraception is treated as a fundamental human right.
Isn't it interesting that not one politician or public figure ever dares to mention it?
150 KW is not huge, considering that ENIAC was a Generation Zero valve machine. I don't know what its clock speed was.
By comparision, the mid-range ICL 1903 mainframe I was using in 1969 ate 40KW with all cabinets powered up: these were the CPU (including 32Kwords magnetic core memory with logic based on 1st gen chips), a disc controller, 2 x 60MB disks, 6 x tape decks, 1350 lpm printer, card reader and paper tape reader plus an ASR33 teletype operator's console. IOW, the 1903 mainframe still consumed 25% of the power needed by ENIAC despite using solid state logic running at a whole 3.5 uS clock speed (28000 cycles/sec).
Maybe a better comparison would be with the HP28s calculator I got in 1990. This, still working perfectly, runs off 3 N size alkalines and, even when used much more regularly than when I got it, has never run for less than a year on a set of batteries.
It seems to me, as a non-USAian, that 'free speech' has a corollary, that you can say whatever you like, but YOU, as the speaker or writer, are absolutely responsible for what you say or write. AFAIK this is its meaning under British Law as well as most Commonwealth members' legal systems. If it doesn't have this meaning under the US Constitution, kindly enlighten me about its legal meaning there.
A law along these lines would get social media off their current hook BUT, and its a big but, they MUST know who published an objectionable or defamatory post so that the lawyers can hit the correct target, namely the author. In other words, it should not be possible to be legally anonymous on these sites. Said another way, you may ask that the site publishes your post with the 'anonymous' tag, but they must not do that unless they know exactly who you are and can provide a legally correct identity in response to a legal request. If they can't do that, then they didn't follow the rules and get to pick up the legal bill as a direct result of failing to identify the author.
In my understanding the above conforms to British and Commonwealth law and may also define to Free Speech as defined in the US Constitution too: if not, please explain.. Most of Europe seems to use a derivative of Napoleonic Law, which I don't understand at all,
Whistle blowing is quite another issue and nothing whatever to do with Free Speech. It must be fully protected in all cases until legally proved wrong. Releasing any whistle-blowing information to anybody other than the intended recipient should be treated as a crime and prosecuted appropriately.
The biggest and bestest speed bumps I've ever seen were on the outskirts of Abu Dhabi. These were at least 30cm high and 5m long, with roughly 1m long on- and off-ramps. They occupied the full width of the road bed, so dodging them was not an option. Even the local taxi drivers wouldn't tackle them at more than a slow walking speed, but many drivers obviously did, because there was a fine collection of interestingly twisted exhaust pipes and mufflers alongside each of them.
Unfortunately I was never there to see a driver donating a new specimen to the roadside collection.
Service seems to be rather too random:
**** I got my first shot last Saturday in the basement of the town's Leisure Centre.
All went very well. When I arrived on time for my appointment there was no queue outside the door, just a 5 minute wait inside in well-spaced seats, got the shot followed by a 30 minute wait in another comfortable chair in case I had a reaction (I didn't). All over in the advertised time.
In summary, a very well-organised process.
**** Today a friend went for her first shot in a West London suburb. She walked to the appointed place in pissing rain, arrived on time but all she found was a locked door and a wet-looking guy stationed outside to tell people that 'all appointments were cancelled'. No explanation offered. No attempt made to e-mail, text or ring her beforehand about the cancellation.
In summary: WTF.
Getting lawyers in sensitive cases to hand-deliver paper copies of sensitive documents to the Court makes perfect sense.
BUT why should, as your story says, these sensitive documents then be hand-typed into a court computer at all. That simply makes no sense at all, since all it does is to make the electronic copy available to hackers, regardless of whether its online or not: never heard of USB memory sticks or SD cards in miscreant's pockets?
The only proper place for a sensitive document that must not be accessed by unauthorised persons is locked in a fireproof safe. If somebody needs a copy of it, use a photocopier and verify that the copy is shredded as soon as it is no longer needed.
PL/1 .... used it a couple of times for large financial systems, on an IBM S/38[*] fault-tolerant box (a national inter-bank funds transfer system), and again on an AS/400 (calculating multicurrency future values).
I wasn't all that fond of PL/1, partly because it was rather a bastard mixture of COBOL data structures and Algol/60-like procedural syntax with exception handlers thrown in got good measure.
But my real beef was its use of exception handlers to trap common occurrences like end of file, indexed record not found, etc and this was annoying because the exception handlers didn't fit nicely into the program flaw - the COBOL statement "READ filename AT END do something." usually makes the logic easy to read because the AT END clause is part of the READ statement while the PL/1 file exception handler is usually outside the file processing loop and IIRC could catch a raft of logically unrelated exceptions - that is to say, unrelated to the program logic flow even the exceptions could all be thrown by the same file.
* The IBM S/38 was a rebadged Stratus system. IIRC the VOS operating system was written in PL/1. PL/1 was also the default programming language for the systems they ran. A nice machine apart from the programming language and, IME more reliable than the better-known Tandem NonStop boxen.
Once again it's up to the noble Lords to provide expertise...
This is only to be expected once you realise that the career path followed by all too many MPs has been:
studied politics at University --> an MP's gofer --> party researcher --> MP
while a large proportion of the Lords were ennobled after successful professional careers in a variety of fields. So, of course there is more real world experience assembled in the Lords than there is in the Commons.
Does anybody know how much of each engine was replaced after each Shuttle launch?
I've never seen anything describing what was done to prepare the engines for their next launch, but a quick search dug up the informatjon that they had a complete tear-down and rebuild after 5 flights, but only visual inspections after each flight: the engines seems to have had a fairly complete automatic checkout system built into them, which runs before each firing.
I wonder how much of this stuff has been left off the RS-25 (SLS) version of these engines as part of converting the design to single flight usage.
A web search finds information that she worked for IBM, but says nothing about what she did there.
In fact, she just seems to be another PHB (Uni, then Civil Service financial bod, followed by financial consultancy and some undefined role at IBM but no indication of any technical knowledge, expertise or responsibility) - yet, she's hired to fix a failing but vital technology project. WHY?
At the current state of the art, its probably easier to lasso an NEO and put it in earth orbit to act as the elevator's counterweight. When that's in place, the factory modules can be winched up for assembly at the free orbital radius point on the tether. This guarantees that there are no micro-gravitic effects in the factory. You would not put the factory on the counterweight because that would leave the factory with a net outward force in its work-spaces.
However, this NEO reuse plot has a major flaw: so far the only suitable sized asteroids we've looked at up close and personal have turned out to be rubble piles, so unlikely to survive being switched from a solar to an terrestrial orbit.
YES! I came here to say something similar.
Everybody in the chain of command, from CEO down to the managers, accountants and designers who decided that MCAS was a satisfactory solution should be made personally liable for their actions with penalties up to and including culpable homicide as well as being permanently banned from future involvement in any organisation that provides, sells or regulates passenger transport services.
This is about the only way that similar people in other organisations will get the message.
To all those working on self-driving systems for surface vehicles: yes, I'm looking at you too.
A while back, on rec.aviation.soaring, there was a thread about towing glider trailers long distances on interstate freeways in the USA, using a Tesla tow car. Glider trailers weigh 1000-1500kg depending on what glider is inside - the trailer typically weighs more than the glider, but have low drag due to having very smooth outer surfaces and a low cross section.
The numbers given by one of the racing pilots, who does this a lot, gave a cross country speed of well under half the Interstate speed limit, with almost all of the speed reduction compared with an IC engined tow vehicle being due to charging time.
In fact, to achieve the average speeds he described, he had to:
- never fully charge the battery due to the much reduced charge rate above about 70% charge
- always calculate the distance to the next charge point and then calculate the charge needed to get there plus 10% to make sure he got there. This gives the amount of charge that has to be in the battery for the next stage of the journey
- only charge the battery to the calculated amount
The only good point in all this I could see was that it was guaranteed that you'd always have time for a leisurely pit stop while you waited for the battery to be topped up to hold the calculated amount of power for the next stage of the journey.
...with UKFSN, which was a genuine one man band. He did quite a good job until he got bored and stopped bothering with the site. My only niggle was that the website just faded out rather than its owner sending us all a "Right, thats it: you've got a month to download your stuff and find another webhost" message, which would have been preferable - at least to me.
However, I didn't loose any web content because, being paranoid about backups and such, all my website content has always been developed and maintained on my house server, which is backed up onto a set of disks which are kept offline in a firesafe. New content is published by FTPing it to my external webhost, which became Zen when UKFSN folded. As a result I always have two copies of my current web content plus at least one up offline backup copy.
Oh yeah, I own the domain names I use. These are hosted by a third party as e-mail and website redirects, so switching webhost and/or ISP is simple: I just change the URLs my domain names redirect to and move my website content to the new webhost. Making this switch is so simple that I don't understand why everybody else who owns a website and/or uses email doesn't do the same.
Look at the UK in the 1960s and 70s.
Surely that was the 50s and 60s - at least that's when the better known British films about union malpractice were made.
IIRC by the time I arrived in the UK in '73, the "winter of discontent" was over and done with. About the only places that were still union-dominated were the newspapers and British Leyland, which was still being run by a rather clueless management who seemed to be fully paid up members of the Old Boy Network, i.e. not dissimilar to ICL management prior to Rob Wilmot. Scargill and the miners strike was still in the future.
The corollary to this is the client insisting that the updates go live NOW despite having not been tested.
That's easy: insist that they sign a note saying that they requested that untested code be run live and that they bear all responsibility for any problems arising.
No signed request: no untested code gets run.
That should make even the stupidest PHB reconsider whether this is really a good idea.
I was at the opening lecture of the 1999/2000 NASM Winter Lecture series which, like all of the series' opening talks, was given by Chuck Yeager. He spoke well and gave a very interesting talk as well as going into other exploits during the Q&A session that followed. The most memorable was about the incident when he snap-rolled a P-51D at a display during a low pass and had the engine quit: yes he had a plan thought out for that! He walked away and I believe the P-51D lived to fly again too.
I'd been tipped off beforehand about book signings, so fronted up afterwards with a copy of 'The Quest For Mach One' and had him sign the colour photo of himself standing in front of the X-1.
I'm very pleased to have been there the day.
...older websites which were written in VB and use Access databases, and are currently orphaned because the Access to SQL Server migration is non-trivial, can, or so it appears from a quick documentation scan, be migrated relatively easily by running their code under Mono. Mono uses ODBC to talk to databases including (by implication) at least some flavours of SQL Server. Given that the ODBC client API is meant to be RDBMS-agnostic, it should follow that, once your code is running under Mono it should be simple to move it to PostgreSQL by migrating the data and then swapping the SQLServer ODBC module for the PostgreSQL one.
But, I probably missed something during that quick scan, so would appreciate knowing what I missed.
I've written systems using various databases including Sybase (SQL Server's parent), Access, Oracle and PostgreSQL and used both ODBC and JDBC but have only given Mono and its VB support a fairly quick preliminary scan to see whether the approach outlined above might offer an easier migration path for a VB+access website than migration to SQL Server. I already know that Mono can talk to an Apache web-server.
The Americans may have been keen on docking, but that was all manually flown. The first successful American docking was in 1966 (Neil Armstrong, Gemini 8) but that was flown manually. NASA continued to use manual docking throughout the Apollo, SkyLab and Space Shuttle programs.
The Russians had an automated docking system up and running first. Its first use was in 1967 and they have used automated docking systems ever since. The only change has the replacement of their original Igla docking system by the current Kurs system.
AFAIK the first US automated docking occurred as part of the first manned SpaceX Crew Dragon 2 mission to the ISS earlier this year.
I remember those days!
The first computer I got my hands on, as in loading cards into the reader, swapping tapes on the tape drives and 8 MB hard disk cartridges on disk drives was an ICL 1902 mainframe in 1968.
That used ferrite core memory with a magic wire woven through individual bits in the first few words: at power-on the memory was zeroed and that wire was pulsed to write the bootstrap into memory.
Unfortunately, it often failed to write a valid bootstrap, at which time you had to enter the bootstrap through a row of 24 hand switches on the CPU cabinet. Good operators had this memorised: we programmers and the newbie operators read it off an octal listing.
... is how did Mr Bogin cut the groove on his vinyl boot disk?
Back in the day I had (and still have) a Garrard 301 fitted with an SME arm and Shure cartridge, but was never able to record anything at acceptable quality until the Akai Dolby-equipped cassette tape decks arrived in the early '70s.
I don't remember there being even a whisper of disk-cutting lathes being available for home use, so just what did our man use to cut his boot disk?
The overhead structure was built in mid air and had no safe way to lower it.
Not quite: it seems that the triangle was built on the ground and then raised by tensioning the cables. There are photos to prove it. Presumably it was raised far enough to let the rest of the equipment be attached before finally raising it up to the prime focal point, but I haven't seen photos showing that intermediate stage.
However, given that one of its initial design aims was to track Soviet satellites and missiles, I'd guess that repairability was never part of its design, which is why it will be demolished rather than rebuilt. It would be interesting to know what its initial design life was: I expect thats been exceeded by a rather large margin.
In any case, it would have become obsolescent when the Square Kilometer Array starts observing, which should be in 2027. The SKA, being a modular design, will be far more maintainable and should be more sensitive as well as providing considerably more resolution than either Arecibo or the 500m Chinese dish ever could.
Adding or replacing any cables looks problematic as there's no place to attach them apart from on the existing towers and apparently no spare attachment points, but the real killer is that it looks to be very difficult to do anything without damaging the main dish reflector: drop anything and another gash is made. Putting up netting strong enough to protect the dish risks causing major damage and may well require making holes in the dish for supporting the protective structure.
IOW, does the main mirror need to be removed while the cables supporting the stuff at the prime focus are replaced?
I am surprised that there's apparently nothing on t'net that describes the construction sequence of the Arecibo Radio Telescope, i.e. that says whether the main mirror was present while, the stuff at the focus was being hung up there or whether it was put in last.
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