Posts by Martin Gregorie

Re: In keeping

The obvious, to me anyway, omission from the list, was Clipzilla. Clippyzilla is just a bit too friendly to MicroSlurp to float my boat.

Educated cable thieves? Shirley knot.

Replacing copper with fiber will only save telcos money if the cable thieves are high class criminals: those with enough know how to tell a fiber cable from a copper one before they dig it up. Those who can't are going to rip the cable out of the ground anyway, and only then realize that what they just pulled is worthless, and probably trash the fiber termination cabinet out of sheer frustration.

Re: Calling Isaac Newton...

See "The Flight Of The Dragonfly" by Robert L Forward for a way to use lasers in the solar system to brake the interstellar craft as it arrives at the target star.

Basically the spacecraft is attached to a flat, circular lightsail thats surrounded by a much larger, slightly concave, annular sail. The combined sail is used for launch. On arrival the spacecraft and its light sail separate from the annular sail and the lasers are turned on again. The large sail focuses the light it receives on the far side of the small sail, which slows the spacecraft down while the big sail continues to accelerate past the target stellar system. This is strictly a one-way trip.

The book describes the system in some detail and gives the dimensions, masses and laser power requirements as part of the story. Worth a read if you want to understand how this type of system might work.

See also "The Mote in God's Eye" by Larry Niven and Jerry Pournelle", this time using the light sail and light from the destination's star as the brake.

@martinusher

The first autonomous model-sized sailplane, aka the ALOFT Project first flew in 2007. It was an off-the-shelf 5m span carbon airframe but fitted with a very interesting autopilot that could navigate round a preset task while finding and using the thermals it needed to finish the task. It was a successful PhD project for its developer/builder/pilot and was allowed to fly in one of the Californian RC cross country competitions. These are multi-day events with each day's task being anything up the 100km round 2 - 4 turnpoints with the pilots flying from the backseat of a convertible or an armchair on the back of a truck as they follow the glider round the task. ALOFT won one day and placed well in the overall comp. It was hand flown for launch and landing and fully autonomous for something like 95-96% of each flight.

A good internet search will find quite a lot about it including autopilot details.

Red v Blue

I've always assumed that the war gaming Red and Blue team terminology owed more to the American post-war world view than anything else, with the implied assumption being that Red always attacks Blue and that of course Blue will never attack Red.

Coming down a rope should be OK, but going up again may be another story.

Climbing a rope in a space suit is almost certainly very hard work because it would mean just using your hands, which are in pressurised gloves that are trying to keep your fingers straight rather than helping to keep them gripped round a rope. IOW, a ladder should be OK, but I wouldn't want to be the poor SOB trying to climb a rope all the way back up that monster, let alone doing it with a sackful of moon rocks over his shoulder. Having your feet in hard moon boots won't help either.

However, I suspect its highly unlikely that a Space-X lander sitting on the moon will look anything like that picture: something like that would have fallen over about 10 seconds after 'engine off'. Any lander will need a much larger and more widely spread set of landing legs than the Falcon 9 uses because its going to land on an unimproved mixture of rocks and dust, not a nice hard, level landing pad or the equally solid deck of a robot landing ship.

Re: Oh, Grandma what big eyes you have.

Apart from anything else, why should we ever trust sensitive data to the people who authorized the Care-Data clusterf*ck?

This centralized approach smells very much like another attempt at the same thing. Once they have tracking data, what are the chances that they WON'T come up with some lame excuse to link in our medical records and then let some third party process the data "because our systems are overloaded with all this tracking" and monetize it "because that pays for a better NHS" or similar lame excuse.

Re: ONU

Actually, once I got past OS/400's major stupid design feature (9 character names and no extensions), it turned out to be a decent OS. What's not to like about the powerful command language and the full-screen prompting (a nicely formatted screen with boxes for entering command arguments, all boxes labelled with name, type of argument, and defaults that works for user-written stuff as well as standard utilities) and predictable command names once you've got your head round the abbreviation scheme that 9 character names requires, e.g. once you know that CRTRPGPGM (short for "create RPG program") runs the RPG compiler its easy to guess that CRTPLIPGM is the PL/1 compiler and CRTCBLPGM is the COBOL compiler. Don't know its parameters? Just type CRTCBLPGM and hit the 'screen prompt' key and there are all the arguments, named and summarised ready to fill in before hitting the 'Do it' key.

ICL's VME/B did the same thing, only better because it used nice meaningful names for commands, with a naming scheme that let you guess names with a good chance of being right, an additional short-form that was equally easy to understand and with an online command lookup system. For instance, to delete a file you used the 'deletefile' command or 'xf' for short. 'x' was always the abbreviation for 'delete', 'f' was always short for 'file' and 'n' for 'new', so you didn't have to be a genius to work out that "newfile(workspace)" would create a new file called workspace and that nf(workspace) would do the same thing. It also provided full-screen prompts for command parameters and these features worked for user-written code as well as for system commands.

Naming consistency is the only thing lacking in UNIX/Linux systems, but at least these have help prompts for most commands as well as manpages and the very useful 'apropos' command for looking up command names.

Bog help those condemned to use other OSen that lack these useful productivity aids.

Re: Retro Progress

I think you're wrong: the Shuttle was the worst. It killed more astronauts than the rest of the global space program, didn't really meet its mission goal of cheap., fast turnround between missions and seems to have left very little technical legacy apart from the RS-25 engines, with the last of those being thrown away on a one-time mission while people are still scratching their heads working out how to get production restarted.

At times it seems that the US program has got lost while too many of various responsible management groups are only interested in lashings of pork than in hitting targets and making stuff work. Space-X is where it is and making progress because Musk is more interested in space than he is in getting richer than he already is.

Re: The first "real", low-cost ISP for the UK

Same here.

I started with Demon in the early '90s, but left them in the early noughties when they refused to support any services other than under my original assigned name. No good, because I wanted to run two independent websites, and this would have required them to host a second domain name for me.

So, I moved to UKFSN with my domain names and associated redirection services hosted by my domain registrar. The two websites and mail handling were run by UKFSN until it went titsup a few years ago.

I'm now with Zen - they handle my mail service and host my websites, with the domain names and redirection service remaining where they were.

Re: Good for data-less phone plans

Likewise. I have a Sammy B2100, which does everything I want as well as being small, rugged and waterproof, but most of my friends have smartphones.

Re: Lucky 13

Errr, no. The O-ring that caused the Challenger crash was nothing to do with any fuel system. Instead it was an essential structural part of one of the two Solid Rocket Boosters. Its job was to seal the joint between two of the stacked steel cylinders that formed the SRB's structure.

The whole assembly was cold-soaked overnight and then launched with the air temperature still below the minimum permitted launch temperature. As a result the O-ring was rigid, rather than resilient, and so was unable to do its job of keeping high pressures inside the rocket casing. This let extremely hot gasses escape, eventually in a strong enough jet to cut through the struts holding the SRB in position.

At that point the SRB pivoted on its remaining attachment, punching a big hole in the external fuel tank and sealing the fate of the crew: there was no emergency crew exit on Challenger.

The launch decision was a classic management error, not helped at all by the perceived pressure of "its live on TV - we can't mess up their schedule or disappoint the viewing public" and compounded by "we've launched below minimum temp before, so nothing can possibly go wrong this time".

There';s a very good, and readable, account of the subsequent investigation and accident analysis in Richard Feynman's book "What do YOU care what other people think?".

Re: Quantum vs COBOL

Quantum and COBOL is the obvious approach.

Follow the path pioneered by CHAPS - all the complex message handling and protocol management was initially done on relatively slow Tandem NonStop fault-tolerant computers, which front-ended the member bank's mainframes. These undoubtedly did, and still do, run COBOL programs that handle all the bank's internal accounts and transactions. The Tandem machines used a very secure encription engine* which handled all outbound message encryption and inbound message decryption. The combination provides a secure, reliable gateway to the CHAPS financial network.

This is a good way of handling security while maintaining network uptime and throughput. At the same time it keeps the internal systems well isolated from network nasties. Of course such a setup isn't cheap, but if manglement thinks its sensitive data doesn't justify the expense, then they deserve to carry the can if/when proved wrong.

[*] This encrypt/decrypt engine could be quantum-based when, if ever, that technology achieves 99,99% uptime, something that Tandem NonStop systems and encryption engines achieved in the early '80s.

How systems were all too often documented in the 60s and 70s

Upvoted, but you missed something: the system design documentation is equally important (1), particularly if, as was common, the program code was uncommented and/or the 'system designer' decreed that some utterly incomprehensible and uninformative scheme for naming variables, paragraphs and sections must be used (2).

The end result was that often the only surviving system documentation was the program source code and puzzling out what the system actually did from the code could be very difficult indeed.

(1) System design documentation was typically hand written, held in ring binders and NEVER updated. Since any documentation of bug fixes or system enhancements was generally discarded when the job was done, or had never existed, what documentation still existed was soon utterly out of date and, consequently, was frequently binned whenever the design office shelves got full. The most extreme case of this I ever saw was at Smiths Industries in Cricklewood, where the System Analysts were kept as isolated as possible from the programing teams and had a policy of immediately scrapping all documentation once the system or patch had successfully gone live. This sort of shambles persisted until PCs and word processing became common in the late '80s. The first purpose-designed system documentation system I met was ICL's Advanced Data Dictionary, which was around on VME/B systems in the late '80s.

(2) The worst example I ever saw was in an accounting package the ICL bureau I was working in mistakenly bought around 1970. It had a coding standard, but it was this:

- data names were all of the form XX99 regardless of their level or usage, so you saw things like this

FD CR01.

01 CR02.

05 CR03 PIC X(15).

05 CR04 PIC S9(6).99 DISPLAY.

..... as a continuous sequence right through all the various card images the program could handle. Then you got to the records on mag tape, which started from MT01 and continued through all records in the various different tape files, started again from LP01 for printed output and - you guessed it - started again from WS01 for all working storage.

- in PROCEDURE DIVISION, use of SECTIONS was forbidden and all labels had to be 5 digit numbers. They weren't even in numeric sequence and, guess what - there were no comments in the entire set of programs. IOW, just what causes this MOVE to be executed, what is it trying to achieve and what will the program do next:

IF CR08 > WS11 MOVE CR15 TO WS23 GO TO 23500.

The bureau wasted a heap of money buying that junk because it was utterly unmaintainable. I never heard whether they got their money back: all I know is that I designed and wrote a replacement using structured and meaningful names and that it was still in use and well regarded when I visited 4 years later - not bad, seeing that in the 70s that sort of system was designed for a life of around 3+ years.

In summary, thanks to this sort of nonsense, why should there be any surprise that the old COBOL systems are still in use?

They can't be replaced simply because nobody knows exactly what they do or how they do it and the cost of going through badly written, uncommented and undocumented code is prohibitive.

As a more current comment, one of the really good things about Java is the javadocs utility. This generates nicely formatted HTML pages from the class and method level comments in source files. So, in principle, the system designers could deliver low-level design as a set of Java pages containing class and method level comments together with method skeletons and the documentation would be up to date because developers would update the comments as they modify the code. Sadly, however, judging by the standard of documentation I see in 3rd party Java packages, yer average developer today still can't be arsed to adequately document what he writes.

Re: A fool and his magnets are seldom parted

I've some neodymium magnets at home and they are powerful things.

Agreed. Neodymium magnets are small (mine are 8mm diameter, 1mm thick), with nicely polished surfaces. So, If you're doing anything with more than one of these magnets at a time they are surprisingly difficult to put precisely where you want them. This is a problem when working on a table-top or workbench, let alone anywhere near your nose and, presumably, while looking in a mirror to see what you're doing.

Re: Technical management tips

Long ago and far away a fellow programmer had made himself a plywood engineer. Worked for him.

Re: Always there are millions like me

The only English book I can think of with a similar sense of humour to the Asterix books is "1066 and all that" by W.C Sellar and R.J. Yeatman - first published in 1930 and AFAIK never out of print since then.

Re: Not so smart tech

Where do you keep the mechanical back-up key

Stuck where the sun don't shine - obviously.

Re: And use food delivery services where you can.

not accepting new registrations (Sainsburys)

That's kind of irrelevant. I was able to sign up with my local Sainsbury's after the curfew was imposed and before the time-banding of purchases was introduced, but, and its a big BUT, its not worth a damn because the website shows no delivery slots are available and the select your slot page has a note at the bottom saying they they can't do deliveries at present and don't know if/when/how they'll do them in future. No reason for non-performance is given.

My local branch doesn't offer an order and pick-up service either.

However, I have a modest proposal: let the Army to do the deliveries. Unlike normal military activities that can't easily be done in isolation, this can be done using their usual vehicles while maintaining isolation and will keep them active, unlike the rest of us with our minimal permitted out-door activities. Besides, I quite like the idea of getting my groceries delivered in an armored car.

Re: "They reckon it’ll only get faster over time"

Radiation at many wavelengths doesn't cause anything to move.

Sure it does: photon impacts, though individually providing just a tiny amount of energy, do push on anything they hit. That is why a lightsail works. This has now been demonstrated by direct experiment.

https://www.planetary.org/blogs/jason-davis/heres-what-we-learned-so-far-ls2.html

Or bigger still..

... when the Linux becomes the prime system kernel and Windows merely an optional desktop alongside Gnome, KDE and XFCE.

Re: Just wait 2 weeks

Why do you think that only the far left would say that?

Its pretty obvious that everybody from ICANN and PIR to XEROX and the so-called 'Activist Investors' think this is a really neat way to make money. Never mind that when they cash out they load the company they bought with the debt they incurred to buy it. That's now Somebody Else's Problem and its perpetrator couldn't care less whether it gets fixed or not.

Anyway, its unlikely the company will have recovered from that before the next shyster does it to them again.

Its been that way since the first time the East India Company had to be bailed out by the Bank of England in 1771 so don't hold your breath waiting for this style of predatory capitalism to be outlawed any time soon.

One good thing that Gates, Bezos and Ellison have in common is that at least they made their money by hard graft rather than by playing shell games with borrowed money.

It was ever thus

If you want a primer on how the Top People ran things in the mid 1700s, read "The Anarchy" by William Dalrymple and compare the behaviour of the bosses then with the current crop. Not a lot has changed.

Re: I wonder how long it'll be before ...

It is a polycyclic aromatic hydrocarbon, after all ...

No, it is not. Graphene is a single layer of carbon atoms, organized in a hexagonal lattice that forms a two-dimensional sheet. It is 100% carbon, so cannot be described as an aromatic hydrocarbon.

- ex-chemist, who wrote his MSc thesis on graphite intercalation compounds.

Intercalation compounds are graphite structures with a layer of an inorganic compound, e.g. Ferric chloride, FeCl₃, in between adjacent sheets of carbon. We'd now call those sheets graphene, but that word wasn't used until Andre Geim and Konstantin Novoselov peeled those carbon layers apart and decsribed them in 2004.

IIRC the cockpit transcripts showed both pilots were at fault.

The transcript recorded the senior (2nd) pilot settling in his seat but did not record him saying "I have control" or the junior (3rd) pilot saying "You have control" in response.

This is the normal control handover dialogue which I'd expect any time control passes from the flying pilot to the non-flying pilot. Since there is no physical connection between the two sidestick controllers and no simulated control load feedback in that Airbus model, neither pilot could feel what the other was doing.

Re: not subect

Also, FAA might not like it, but below a minimum flight level, you are NOT subject to FAA rules

That depends on where you are in any country.

In the UK class G airspace starts at 400 ft AGL, which is also the maximum permitted height for UAS, i.e. RC models and drones, operation. However, a UAS cannot be flown within an ATZ (a circle of normally 2 nautical miles radius from the midpoint of the runway of a licensed airfield) or in Control Zones, such as the London CTR. Both ATZ and CTR airspace starts at ground level. CTR airspace is typically class A - D airspace as well, which means no entry except when you're following directions from ground control.

So, no you CAN'T fly a drone in Hyde Park or on Clapham Common because both are inside the London CTR. You can, however, fly a control-line model if the landowner allows it because these models are tethered to the pilot by the lines used to control the model.

In the USA things differ in detail, but the general rules are the same. I just dug out my copy of the FAA regulations from 2001. FARs part 71 defines the airspace classes and what can be done inside each of them. Only classes E and G have a lower limit - 1500 ft AGL for class E and 1200 ft AGLfor class G airspace. Since that is the bottom limit for aircraft ops, it would appear, unless the FARs have changed since 2001, that you can legally operate a drone or RC model up to 1200 ft in class G, up to 1500 ft in class E and not at all in class A,B,C or D airspace in the USA.

Disclaimer: the FARs are written in an obtuse, legalistic fashion where later statements can and do amend or override earlier statements. They are hard to understand because of this. This means that I could have easily have misinterpreted them. They also jabber on: the FARs applicable to glider pilots occupy 101 pages of A4 paper, while the much more readable UK "Laws and Rules for Glider Pilots" fit comfortably onto 69 pages of A5 paper.

Re: "Extreme testing"

"Extreme testing" blah blah. If you publish mission critical code or make it available for public use you should have a regression test set that is:

(a) written from the specs, NOT the code

(b) is updated whenever the specs change

(c) used to check all code revisions, which MUST pass it with no exceptions before the code is released or goes live.

If you publish or maintain mission critical code and don't have such a regression test suite for it, you're only playing at writing software. If this describes you or your organisation, you'd best start working on that regression test suite. Fast. Don't forget to include it if/when you publish the code and treat any reported omissions as seriously as you treat software bugs.

Re: Remind me again ...

Upvoted.

All daily backups here are automated and made to local media, which is permanently connected to the server but unmounted when not being written to. Backup times are under 15 minutes, so this makes this backup pretty much impervious to everything but a mains spike or a house fire.

System updates are NOT automated because I want to make all backups to local media. Each backup is written to the oldest instance of a separate backup cycle, with all generations stored offline in a fire-safe except the one being written to, and immediately followed with a manually triggered system update and reboot. These backups should survive even the house fire and offer protection against a borked system update.

This is the best way I can think of to keep my data safe and under my control at all times. As a bonus, I don't need to rent any cloud storage for backups or worry if they might be lost in a data centre crash and its cost is minimal.

Re: ISP should be treated differently

I guess you didn't know that scanning and storing the addresses on envelopes has been standard practice in many countries for years.

So what? Most people, and many advertisers and companies, don't put the sender's address on the outside of the envelope. IOW, while the owner of a pipe carrying e-mail etc knows both sender and recipient as well as the content of an unencrypted message, in a large majority of cases the Post Office or mail carrier does not know who sent to mail or whats in it.

Re: Not all good...

Don't worry - it'll be fine provided it hasn't got 737SLS written on it.

Re: If FTP is disliked what about TFTP ??

No need to bother with HTTP/S and other such if you're moving on from FTP because many of the better FTP clients also support SFTP - that's an SSH variant so is encrypted - as well as FTP.

If you're lucky, your favourite FTP client is one of them - in my case that's gFTP and it handles SFTP just fine, though it calls it SSH2. Same goes for FileZilla.

Re: This reminds me of older business model than Microsoft

I don't really give a monkeys - I saw this attitude in person back in the mid-70s. Even the IT guy and the comptroller had no good words for the IBM SE's who visited the small Long Beach, NYC company, which I was designing and building a system for. They bought an ICL 2903 to replace their System/3, at least partly to get away from IBM. That companies IT people hadn't a good word to say for IBM and their IT guy had been blackballed by them for buying 3th party disks at a previous workplace.

However, I must say that 15 years later, when I did a lot of work on AS/400 kit I was well impressed with the quality of the hardware. No hardware glitches or software bugs in the 18 months we worked on that project. I liked OS/400 quite a lot too - and would have liked it more apart from its rather pathetic non-hierarchic filing system, stupidly short (9 character) names and the horrid RPG3 that was pushed as its everyday programming language.

Do you really not know that the New Blue Passports are being Fabrique en France rather than Built in Blighty?

Re: Isn't THIS why we've got to teach 2nd-graders how to "code", rather than how to think?

Critical thinking and analytical skills are the last things our self-proclaimed elders and betters want to see the general population understanding and using. They know very well that if this ever comes to pass they, along with the Sirius Cybernetics Sales Engineers, will be first against the wall when the revolution comes.

Re: Fixing MCAS

Good point, but with the caveat that the calculated AOA may only be used as a check on the MCAS system and must not ever be used to control the aircraft.

Re: "the FAA remains focused on [..] returning the Boeing 737 MAX to passenger service"

With any luck the 737MAX will be obsolete and unsaleable by the time it gets re-certified, if it ever does. Failing that, fixing the design and avionics followed by conversion training for the aircrew who will fly the redesigned, modified and re-certified air-frames will be so expensive that no airline will buy them. Unless, that is, Trump's last act at the end of his second term is to mandate its use by all US airlines.

Not that I care. At least the 737MAX fiasco, coupled with cancellation of the one Ryanair route I'd want to use has given me the kick I needed to never fly with them again. I hope they choke on the 737MAX options they picked up cheap after the first crash.

Re: Forget bringing a towel when hitch hiking the galaxy

Good call, though the Dark Star writers nicked that bit, meteor collision and all, from an older SF short story. One of Ray Bradbury's IIRC.

Re: EE 'Doc' Smith

I've always lumped 'Doc' Smith and A E van Vogt together as authors of fairly incoherent, BEM filled rubbish that I gave up while still a teenager.

But a (very) recent rediscovery is just how good some of Fred Hoyle's books are, especially 'The Black Cloud' and 'Ossian's Ride'.