As well as Concorde government subsidies have bought us things like the Apollo programme, the Channel Tunnel, the trans-continental rail[way|road] in the US, the Internet, the world-wide-web, the first digital programmable computers, and the first inter-continental telegraph cables.
Ironic that you should mention the first digital programmable computers in a thread with this name - the first commercial one was the LEO (Lyons Electronic Office) - funded by a chain of tea-shops rather than government. And it would be a vile calumny to suggest that there is little difference in the UK.
when I was harrassed and threatened with a lawsuit by net.kook Right Reverend Colin James III,
Ah whatever happened to CJ 3.01? He came after me as well, but couldn't find out where I worked. I had to contact everyone who shared my name and had a net presence to warn them he might come after them as well.
My particular offence was to contradict him when he said that the Eiffel language was compulsory for European-funded software projects (of which I managed a large number).
When I were a lad, I learnt to program in FORTRAN (none of your poncy lower-case) 4 on a Modular 1 - 64kw of real ferrite core and thirty clanking teletypes smelling of warm oil. When it crashed - which was as often as a low-memory Windows '95 machine running Word - half the time you could reboot without reloading because the OS was still there in the core memory.
If you did reload, you met the true face of admin hostility. None of these wimpy psychological measures like tempting the sysadmin to type rm -rf while running as root. No, you loaded the OS using a high-speed paper tape reader. Now it seems that no-one ever worked out how to reel in tape as fast as it could be read, so the tape would spew out into a bucket. A plastic bucket. Which would act as a van der Graaf generator to build up a nice large static charge for the next person to try to pick it up.
Same at Cambridge. Theoretically I shared with a blues boatie for a couple of subjects - of course he never turned up. The down side is that there's nowhere to hide, and I'm just not that good at physics.
Switching to Dovecot was pretty easy and I noticed an immediate performance increase. The support of Maildirs is a must-have.
I use mbox at the moment with a different server. Is there an easy way to convert existing mboxes to maildirs? The obvious way would be to use a mail client to move messages from one to the other, assuming Dovecot supports both simultaneously. Would this work?
1) There are far too many other slow aircraft flying at or near Concorde altitudes. Considering the fuel costs involved in getting to supersonic speeds (max drag between 0.97M and 1.4M), the economics of trans-continental supersonic flight would require sterile airspace for end-to-end clearance. The lobby group for bizjet owners would never let that happen at their expense.
Other than exotics like the U2, what planes routinely fly at the 60000' cruise altitude of Concorde? Most planes I fly on cruise at about 35000'.
In the aerospace annex of the Deutsches Museum in Munich there's a remarkable plane. Unfortunately I don't read German, but it's a transport carrying about 16-20 people in the fuselage. The two underwing jet pods look normal at first, until you notice there's no exhaust at the back - they're Pegasus engines as in the Harrier. As far as I can tell, it's a Do-31, with eight further engines on the end of the wings (which at the time I took for passenger pods, since they have "windows" and the inlet and exhausts were closed off.
It seems that AC Clark got things about right in "2001" when Dave Bowman goes from the pod into the emergency airlock the hard way.
No, it doesn't work. There have been studies of how long it takes you to lose consciousness, and in a vacuum it will only take 2-3 seconds, although it will take you longer to die. It's to do with the way that haemoglobin takes up or releases oxygen. If you graph percentage oxygen content against the partial pressure of oxygen, there's a S curve. Up to something like the partial pressure corresponding to 15000', haemogloblin is almost saturated with O2. At lower partial pressures (such as found in the blood vessels supplying working muscles), the oxygen is dumped straight back out, which is exactly what's needed for oxygen transport. Unfortunately if the partial pressure is low because you've blown a seal in your spacecraft, your entire blood supply dumps oxygen as gas, usually in the wrong places. Probably gives you a really nasty case of the bends for the short time you can register it.
Remember that for embedded stuff, you want low power consumption.
I didn't mention imbedded stuff. I'm only interested in building a computer, not using it for something practical - there's plenty of off-the shelf stuff for that.
Learn C. It's pretty similar to Java, but is far more suitable for writing embedded controller software. Remember that you are going to be controlling things, not drawing widgets on a screen, so an OO language is not really necessary (or even desirable). Instead, you will be reading and writing IO ports, which will involve a certain amount of bare metal programming. Java won't really let you do this. You could use FORTH, which was invented for writing controller software for steerable telescopes.
Umm, how shall I put this? Are you old enough to remember BCPL? That was when I started using C-family languages, though I did more work with K&R. I'd imagine almost everyone here is familiar with at least ANSI C. I just happen to prefer Java for playing around. Either language will need some tailoring of the run-times to work on a new machine - admittedly C would probably be easier, but it would be interesting to look at what's involved in porting a JRE.
BTW, with suitable attention to issues like garbage collection, yes you could use Java to run a soft real-time system such as ABS. Not what I'd choose for such a simple problem, but Java on a modern processor will run a lot faster than assembler on some of the old crates I used to do real time work on, and ABS is a really undemanding problem. Memory consumption is more of an issue.
This is Engineering work, and Slashdot barely qualifies for basic programming advice.
Ah, rubbish. I asked for pointers on where to start, not detailed circuit layouts, and I've got a load of useful responses (thanks guys!). That's exactly what/. is good at. Now I'm going to have a look at what FPGAs can be used for - I get the impression they could be useful for building the device, but I'm not sure how yet as they came in after my time.
This looks like fun, but a bit beyond me. I've wondered about building an OISC - should be the simplest CPU to build, but a real bear to program (do bears program in the woods?). But using 74 series components? Doesn't he know Real Men knaw individual transistors out of solid silicon?
Yes, for actually getting stuff done I like the TINI - nice to work with and very cheap. I've not tried the SNAP but I've heard good things about it. However they're basically ready-built whereas in this case I'm interested in building from the CPU up - I suppose mainly to see if it can still be done.
No, I don't like pen and paper because I have difficulty reading it fast enough even with a single-voice instrument, and I don't memorise pieces. Manuscript for organ or piano would be completely beyond me. I may also want to write out choir parts, and it's easier for other people with clean printouts.
The other problem is that I make too many mistakes and my manuscripts would end up looking like a battle zone.
Then there are the greedy users - you know who I'm talking about: the ones that run Excel, Word, Acrobat Reader, AIM, MSN Msgr and several IE windows all at once...
Now, granted, they could get a "better" computer (well, if not for our budget anyway) - but for the purposes of their job they could as well be using a 400mghz Win95 box with 32MB RAM and a 500MB hard drive.
Sorry, I'm not buying that. There's nothing "greedy" about expecting the computer to work for you, rather than vice-versa. I usually have more than 30 windows open, including most of the MS Office apps and a load of emails in Outlook. I've got good business reasons for having that much state on my desktop and I really don't care if someone in IT thinks that I can do word-processing and email on a pensionable '95 machine. And yes, it is unacceptable when Win2k crashes and looses my state (and yes, I do know the difference between thrashing and crashing). Why should any OS ever be excused from crashing?
I remember reading that the right to trial by combat wasn't removed until 1780 somthing...
I remember a couple of brothers in Edinburgh wanting trial by combat about 10 years ago. Althought the law is still on the books in Scotland, it was held to have fallen into desuetude - probably much to the relief of the Queen's Champion, who was 80 years old at the time.
Fuel is cheap. Maintenance costs the world, and the Concorde is the most expensive-to-operate airliner in the world.
Parent was referring to fuel costs as reason for axing Concorde. Maintenance is ususually expensive
So far as I know, it has NEVER shown a profit, so I take your contention with a large grain of salt. I'd love to see a citation if you happen to have one. I'd like to be proven wrong! I think it's a great aircraft.
There are a few third parties references to BAsaying that the service had been profitable (e.g. here and here), but I can't find an authoritative reference for you. Old copies of the company annual report stated this, but I can only find the current report online.
In any case, "profit" here means in the accounting sense of making a profit during one year, not lifetime profit including development costs. Frankly, I don't care: we could afford it and it was worth doing.
Why doesn't the concorde still fly? It burns WAY too much fuel to be profitable.
There's a Concorde flight twice daily over my house. They stop flying in October, but that's because of the cost of upcoming refits and because Airbus will not maintain them in the future. They appear to be highly profitable at the moment.
Fuel costs just aren't an issue: do the maths. An average load for a transatlantic flight is probaly about 100 passengers, paying about £5000 each for a return journey, i.e £0.25M revenue for one journey. Fuel capacity is 96 tonnes, which would cost about £9000 to fill.
Slashdot Mirror
Ironic that you should mention the first digital programmable computers in a thread with this name - the first commercial one was the LEO (Lyons Electronic Office) - funded by a chain of tea-shops rather than government. And it would be a vile calumny to suggest that there is little difference in the UK.
They're still in service, and will be for a few days. Does anyone else find it amusing that it's already taking on the mythical aspects of Aurora?
Sheesh guys, don't bury the old girl 'til she's dead. Concorde still goes over my house every day, and will do for the next eleven days.
Ah whatever happened to CJ 3.01? He came after me as well, but couldn't find out where I worked. I had to contact everyone who shared my name and had a net presence to warn them he might come after them as well.
My particular offence was to contradict him when he said that the Eiffel language was compulsory for European-funded software projects (of which I managed a large number).
When I were a lad, I learnt to program in FORTRAN (none of your poncy lower-case) 4 on a Modular 1 - 64kw of real ferrite core and thirty clanking teletypes smelling of warm oil. When it crashed - which was as often as a low-memory Windows '95 machine running Word - half the time you could reboot without reloading because the OS was still there in the core memory.
If you did reload, you met the true face of admin hostility. None of these wimpy psychological measures like tempting the sysadmin to type rm -rf while running as root. No, you loaded the OS using a high-speed paper tape reader. Now it seems that no-one ever worked out how to reel in tape as fast as it could be read, so the tape would spew out into a bucket. A plastic bucket. Which would act as a van der Graaf generator to build up a nice large static charge for the next person to try to pick it up.
And you tell the young these days...
Same at Cambridge. Theoretically I shared with a blues boatie for a couple of subjects - of course he never turned up. The down side is that there's nowhere to hide, and I'm just not that good at physics.
I use mbox at the moment with a different server. Is there an easy way to convert existing mboxes to maildirs? The obvious way would be to use a mail client to move messages from one to the other, assuming Dovecot supports both simultaneously. Would this work?
Other than exotics like the U2, what planes routinely fly at the 60000' cruise altitude of Concorde? Most planes I fly on cruise at about 35000'.
Not so sure they are for different markets - there's a bright yellow DUKW with seating in the back that does tours in central London.
I bow to your superior knowledge of real-time programming.
In the aerospace annex of the Deutsches Museum in Munich there's a remarkable plane. Unfortunately I don't read German, but it's a transport carrying about 16-20 people in the fuselage. The two underwing jet pods look normal at first, until you notice there's no exhaust at the back - they're Pegasus engines as in the Harrier. As far as I can tell, it's a Do-31, with eight further engines on the end of the wings (which at the time I took for passenger pods, since they have "windows" and the inlet and exhausts were closed off.
No, it doesn't work. There have been studies of how long it takes you to lose consciousness, and in a vacuum it will only take 2-3 seconds, although it will take you longer to die. It's to do with the way that haemoglobin takes up or releases oxygen. If you graph percentage oxygen content against the partial pressure of oxygen, there's a S curve. Up to something like the partial pressure corresponding to 15000', haemogloblin is almost saturated with O2. At lower partial pressures (such as found in the blood vessels supplying working muscles), the oxygen is dumped straight back out, which is exactly what's needed for oxygen transport. Unfortunately if the partial pressure is low because you've blown a seal in your spacecraft, your entire blood supply dumps oxygen as gas, usually in the wrong places. Probably gives you a really nasty case of the bends for the short time you can register it.
Sorry chaps, this is Ask Slashdot. You need the next section over - Flask Slashdot.
I didn't mention imbedded stuff. I'm only interested in building a computer, not using it for something practical - there's plenty of off-the shelf stuff for that.
Learn C. It's pretty similar to Java, but is far more suitable for writing embedded controller software. Remember that you are going to be controlling things, not drawing widgets on a screen, so an OO language is not really necessary (or even desirable). Instead, you will be reading and writing IO ports, which will involve a certain amount of bare metal programming. Java won't really let you do this. You could use FORTH, which was invented for writing controller software for steerable telescopes.
Umm, how shall I put this? Are you old enough to remember BCPL? That was when I started using C-family languages, though I did more work with K&R. I'd imagine almost everyone here is familiar with at least ANSI C. I just happen to prefer Java for playing around. Either language will need some tailoring of the run-times to work on a new machine - admittedly C would probably be easier, but it would be interesting to look at what's involved in porting a JRE.
BTW, with suitable attention to issues like garbage collection, yes you could use Java to run a soft real-time system such as ABS. Not what I'd choose for such a simple problem, but Java on a modern processor will run a lot faster than assembler on some of the old crates I used to do real time work on, and ABS is a really undemanding problem. Memory consumption is more of an issue.
Ah, rubbish. I asked for pointers on where to start, not detailed circuit layouts, and I've got a load of useful responses (thanks guys!). That's exactly what /. is good at. Now I'm going to have a look at what FPGAs can be used for - I get the impression they could be useful for building the device, but I'm not sure how yet as they came in after my time.
This looks like fun, but a bit beyond me. I've wondered about building an OISC - should be the simplest CPU to build, but a real bear to program (do bears program in the woods?). But using 74 series components? Doesn't he know Real Men knaw individual transistors out of solid silicon?
Certainly a good idea - it's just I have this allergic reaction to the aesthetics of Forth which I suppose I'll have to overcome.
Yes, for actually getting stuff done I like the TINI - nice to work with and very cheap. I've not tried the SNAP but I've heard good things about it. However they're basically ready-built whereas in this case I'm interested in building from the CPU up - I suppose mainly to see if it can still be done.
No, I don't like pen and paper because I have difficulty reading it fast enough even with a single-voice instrument, and I don't memorise pieces. Manuscript for organ or piano would be completely beyond me. I may also want to write out choir parts, and it's easier for other people with clean printouts.
The other problem is that I make too many mistakes and my manuscripts would end up looking like a battle zone.
Sorry, I'm not buying that. There's nothing "greedy" about expecting the computer to work for you, rather than vice-versa. I usually have more than 30 windows open, including most of the MS Office apps and a load of emails in Outlook. I've got good business reasons for having that much state on my desktop and I really don't care if someone in IT thinks that I can do word-processing and email on a pensionable '95 machine. And yes, it is unacceptable when Win2k crashes and looses my state (and yes, I do know the difference between thrashing and crashing). Why should any OS ever be excused from crashing?
I remember a couple of brothers in Edinburgh wanting trial by combat about 10 years ago. Althought the law is still on the books in Scotland, it was held to have fallen into desuetude - probably much to the relief of the Queen's Champion, who was 80 years old at the time.
There's no such thing as British common law. The law of Scotland is based on Roman law.
Parent was referring to fuel costs as reason for axing Concorde. Maintenance is ususually expensive
So far as I know, it has NEVER shown a profit, so I take your contention with a large grain of salt. I'd love to see a citation if you happen to have one. I'd like to be proven wrong! I think it's a great aircraft.
There are a few third parties references to BAsaying that the service had been profitable (e.g. here and here), but I can't find an authoritative reference for you. Old copies of the company annual report stated this, but I can only find the current report online.
In any case, "profit" here means in the accounting sense of making a profit during one year, not lifetime profit including development costs. Frankly, I don't care: we could afford it and it was worth doing.
It's a very old urban legend. As far as I can tell, the chickecn cannon was developed in the UK to test the De Havilland Comet.
There's a Concorde flight twice daily over my house. They stop flying in October, but that's because of the cost of upcoming refits and because Airbus will not maintain them in the future. They appear to be highly profitable at the moment.
Fuel costs just aren't an issue: do the maths. An average load for a transatlantic flight is probaly about 100 passengers, paying about £5000 each for a return journey, i.e £0.25M revenue for one journey. Fuel capacity is 96 tonnes, which would cost about £9000 to fill.