Escape or Break?

In terms of usability and function within applications and within the OS itself—what is the difference between the Escape key and the Break key?

(I’m sure as has been pointed out to me in other posts that this is somewhere in the style guide but I think it might be useful to get it out in the open here for any developers who are interested!)

For starters, Alt/Brk will get you out of a mess with an application that has stalled and allow you to quit it where Escape doesn’t, and Ctrl/Brk will restart your machine, unlike any Escape combinations. Be aware that it does this without any shutdown warnings and transient data will be lost, including the CMOS settings if they have not already been saved (or any changes to them, that is)!

Escape will halt a simple single-tasking BASIC program, or, for example, the Boot sequence if you hit it at an apposite time. Obviously, this needs to be after the keyboard is recognised (USB!).

Be aware that it does this without any shutdown warnings and transient data will be lost,

You aren’t running a patch to trap that errant eighties hangover?!?

Aside from Alt/Brk and Ctrl/Brk, I’m not sure there is a difference. The Wimp sends the same key code for both keys.
I didn’t spot any mention of the Break key in the RISC OS 3 style guide.

You aren’t running a patch to trap that errant eighties hangover?!?

No – and if I were I wouldn’t mention it here; Glen wanted to know things about how the OS currently behaves wrt Break, and that’s what I told him.

Ctrl/Escape doesn’t do this, so it’s a real difference.

‘Phone back on yet? Mom’s birthday Sunday!

No – and if I were I wouldn’t mention it here;

≪facepalm!> 🤦
I was referring to the behaviour of immediate reset.

Phone not on. Contacted Orange again as heard nothing in 48h, have them mom’s mobile again… Got another text to say it’ll be fixed by 6pm Friday. Can’t quite see that somehow…
If it isn’t, I’ll dig up some Econet cable and splice the two ends together.

If it isn’t, I’ll dig up some Econet cable and splice the two ends together.

Not the safest of hobbies, ever wondered what powers the phone at the customer end?

A current loop that is nominally -48VDC.
The ringer is nastier, 90VAC nominal but you can get a phone to ring quite well with an American travel transformer that outputs 110V from the mains. Thankfully my landline is VoIP so there’s only the -48V to deal with.

(misspent childhood not wanting to put coins in the school phone when I could buy sugary things instead….)

The ringer is nastier, 90VAC nominal but you can get a phone to ring quite well with an American travel transformer that outputs 110V from the main

Not suggesting you try this, But I was interested to find that a 230V LED lightbulb uses only passive components to output the DC for the leds. There is two identical circuits feeding half of the leds (in series) each.
Looks like a high value resister, a hV input capacitor, 4 diodes as a bridge, then a smoothing capacitor and higher wattage resistor on the output.
I guess the safety factor comes from the fact that carbon resistors fail by open circuiting. It can be the other way round for diodes being used at 230v in my experience.
The bulb is from China and has CE printed on it. I guess light bulbs are generally not in places where they could start a fire, but perhaps it could drop stuff on to paper etc.

Looks like a high value resister, a hV input capacitor, 4 diodes as a bridge, then a smoothing capacitor and higher wattage resistor on the output.

Sounds like a capacitive dropper: pretty standard for a “cheap” LED drive circuit, because done correctly it’s small and effective.

It’s worth highlighting that (unlike a properly isolated driver with transformer and control circuitry¹) it does not isolate the supply for the LEDs, and so the whole LED and heatsink assembly is live and will kill if you touch it when it’s powered on. If you take the plastic cover of the “bulb” (assuming it had one), touching the metal inside can easily be fatal.

I guess the safety factor comes from the fact that carbon resistors fail by open circuiting.

Pretty much: it’s not uncommon when a fuse is too expensive. The whole dropper circuit is current limited, anyway, as the capacitor’s reactance is what is being used to drop the voltage down from 240Vac to the LED string voltage without undue power loss.

The bulb is from China and has CE printed on it.

It’s worth pointing out that having CE printed on something from China, and that same something meeting the requirements for a CE Mark, are two totally separate things… It depends on where you bought it: a reputable “high-street” shop and you’re probably OK²; online for a couple of quid including shipping direct from China and you might not be.

¹ For safely, note that not all drivers with what look like transformers are isolated. The outputs of some are just as live as that of the capacitive dropper.

² But not always. Several UK “names” have had embarrassing recalls of lethal electrical items like USB chargers.

It’s worth pointing out that having CE printed on something from China, and that same something meeting the requirements for a CE Mark, are two totally separate things

Note that the CE and “China Export” symbols look very similar!

the whole LED and heatsink assembly is live and will kill if you touch it when it’s powered on

I would have thought the voltage would be dropped at the point of connection to the leds. The manufacturer has left quite a few solder connections exposed in places where you could touch them. If everything /did/ short you would have 230 volts, maybe even after some leds have blown. A short like that should trip the breaker I think. The RCD trip would protect you if you touched one live wire, but if you had one hand on live and one on neutral it wouldn’t know the difference from any other electrical load. Well maybe if you had a path to ground as well it might trip and save you.

It crosses my mind that newly wired premises ought to start wiring lighting circuits low voltage, probably DC, with an isolating PSU at the consumer unit. The currents required to run low voltage lighting nowadays are so small there’s no point having 240V for it.

Obviously the power circuits still need 240V.

(I just installed 12V LED lighting in our attic, where the ceiling height never allowed us to have anything but desk lamps before. Whee! But the switches are 240V, so there are three separate PSUs for the three circuits, and the PSUs aren’t always on.)

It crosses my mind that newly wired premises ought to start wiring lighting circuits low voltage, probably DC

The 230V wiring could be connected to a transformer back in the box, I bought a 12v transformer to power lights in the bathroom, which requires dear IP66 fittings otherwise. I think you still need reasonable waterproofing with DC.
The problem is the commercial led lights available like the 56w double fluoro lookalike I bought come with transformers built in and I’m not sure what dc voltage they run at. It might not be 12v. I think 48V is used for off the grid houses, pricey stuff though. The 230v cable could do either job, you would have to change a line of lights at a time though. I think 230V wiring gives you the most flexibility for whatever you might change to later. You are right 12v would be a safer system, there were lives lost in australia when they mounted a largescale roof insulation inititive. I think it had something to do with staples and foil on the insulation.

It crosses my mind that newly wired premises ought to start wiring lighting circuits low voltage, probably DC, with an isolating PSU at the consumer unit.

I predict that being whinged about by thousands of oh-so-city-and-guilds-qualified electricians.¹

They’ve not had the legal monopoly on household wiring for that long and introducing low voltage safe stuff would reduce their work prospects.

The fact that it is a damned good safety idea might carry the day though. On which thought, how many domestic items really need 240 volts?

¹ I have a friend with a career involving power station level metering who was challenged about whether he’d got the correct certification by a bog standard electrician (said electrician had just done a wiring job that a six year would have been ashamed of)

On which thought, how many domestic items really need 240 volts?

Cookers, immersion heaters, large fridges / freezers, lathe, compressor, storage heaters, electric fires
for starters

I seem to have lost the thread…

I did try interrupting the boot sequence with Break and it came up with a dialog box which said “Escape” but didn’t seem to stop the booting process!

All these questions about keys and the like are because I am currently designing a compact keyboard layout which is RISC OS friendly. Since the number of keys are limited (I’m going for a small re-programmable keyboard so I have more room for coffee on my desk) I have decided that I am going to make my Break key a normal key and the Escape key will be active if you hold down Function and press the key to the left of 1 which normally has ` ¦ ¬ (and degree on RISC OS but I’m currently on Windows…)

As far as phones and electricians go I don’t have much to add!

I have a friend with a career involving power station level metering who was challenged about whether he’d got the correct certification by a bog standard electrician (said electrician had just done a wiring job that a six year would have been ashamed of)

8~) I anticipate some interesting test cases involving experienced graduate electrical engineers. My own degrees are in Mech. Eng. and Maths, not Elec, but I used to do all my own domestic wiring (and occasionally bits and pieces for other people). This house was all done before the new regulations, honest, guv.

I really don’t know why I kept all those old reels of red and black cable. Can’t imagine.

Cookers, immersion heaters, large fridges / freezers, lathe, compressor, storage heaters, electric fires for starters

None of that needs 240V. The same things exist in America (110V) and much of the stuff you mention is, at work, running off three phase (which is probably more important than the choice of voltage).

For me, it seems as if a growing number of my random assorted things has a USB connector and would be happy with a decent 5VDC.
My bedroom in England had a box with banana plugs and 12VDC. Ran the CB most of the time.

Cookers could run off 12V, but the thickness of the wiring would be stupid. Anything that’s drawing a few hundred watts or more, (kettles, cookers, vacuum cleaners, electric drills, heaters) really needs a high enough voltage to be potentially dangerous. 5V and 12V are fine for light loads. Even lighting wasn’t really sensible on low voltages until the advent of LED lighting, or possibly compact fluorescents.

@Rick Murray
bq. None of that needs 240V. The same things exist in America (110V) and much of the stuff you mention is, at work, running off three phase (which is probably more important than the choice of voltage)

My understanding was that in the USA they use split phase to the home and fixed items like cookers run 220V and general lighting, pluged in equipment uses 110V

110V is half of 240V (near enough). For the same power, you need double the amps – which means twice the thickness of cabling (or twice the voltage drop and four times the heat dissipation in the cabling). This isn’t really a big difference, compared with the difference between either 110V or 240V and 12V. And 110V isn’t very much less dangerous than 240V, either – either is potentially lethal.

What all this has to do with Escape or Break, I’m not sure… 8~)

What all this has to do with Escape or Break, I’m not sure…

AC volts gives you 2 x frequency chances to let go per second (Escape).
Unfortunately so does DC (Break)

I would have thought the voltage would be dropped at the point of connection to the leds.

It is, but you’re confusing the output voltage with the concept of it being ‘live’. Even 5V from a dodgy USB power supply can be lethal if it isn’t isolated from the mains.

A short like that should trip the breaker I think.

Maybe not, as the dropper is current limited. Those little plug-in nightlights quite often just short the LEDs out to make them go off during daylight, which means that they continue to consume the same amount of power while off during the day as they do when on at night…

The RCD trip would protect you if you touched one live wire

I’d prefer not to rely on that one, if at all possible… :-)

The same things exist in America (110V)

In America, things like washing machines, tumble dryers and cookers are usually powered off a two phase supply which is around 220V.

I’d prefer not to rely on that one, if at all possible… :-)

When working on household electrics I always liked the comfort of a fuse holder poking into my bum cheeks because then I knew it couldn’t possibly be in a position to allow the circuit to be live. Paranoid maybe, but still breathing.