The Men Who Made Us Spend

[dennis]

Would that be a rebadged GEC one made in wales?

[Jethro_uk]

Alternatively their design and build quality was as high as those of the British car industry ....

[Johny B Good]

But probably not a desktop PC. Many years ago PC Pro magazine tested an office full of PCs for mains voltage dip tolerance and discovered that the PSUs (possibly AT rather than ATX) didn't disassert the PG line until the voltage dropped just below the 186 volt mark, re-asserting the PG signal at a voltage just above this remarkably consistent 186 volt point. At a low of 187 volts, the PC should have kept going according to PC Pro's findings.

Incidently, if you witness a brief sub second outage whilst using a desktop PC, don't worry about the possibility of 'silent data corruption'. It'll either keep running ok or else reset itself just before the internal voltage rails dipped below the minimum specified for reliable operation of the logic chips.

The worst consequence of such a brief dip or dropout of mains supply is that you lose the editing session changes you were in the middle of doing, if you were in mid flow editing a file at the time and be faced with the delay of a disk check when it reboots.

The PG signal from the PSU is there to limit the consequences of a sudden power outage to a matter of mere inconvenience as opposed to a total disaster if no such facility had been incorporated into the design of the IBM PC and its clones.

Incidently, that 187 volts was way outside of the tolerance limits the PSUs (Public Supply Utilities) are legally obliged to conform to, even assuming a nominal 220v supply as opposed to the 240v typically in use UK wide.

I believe the tolerance used to be +/- 10% of the 240v nominal voltage. All that's been done in regard to 'harmonization of mains supply voltage' is to use an asymetric tolerance (+6% -14% ?) that encompasses the limits for appliances rated for a nominal 230v supply, leaving the mains supply voltage set for 240v in the UK and likewise

220v on the continent.

The only 'appliance' that's acutely sensitive to voltage variation is the humble mains voltage tungsten filament light bulb which has largely been displaced by the more tolerant electronically ballasted CFLs and LED lamps (I think the 12v halogen lamps enjoy the benefit of an electronic "12 volt transformer" to buffer them from mains voltage variations).

Presumably, a day _will_ come when the mains supply voltages are actually adjusted to the harmonised voltage of 230 but, afaiaa, this hasn't happened yet.

[Johny B Good]

I suspect you meant the 8088 / 8086 processor rather than the predecessor to the Zilog Z80 cpu used in the Sinclair ZX80, ZX81 and Spectrum computers of the early 80s.

[The Natural Philosopher]

We exported to a captive market called the commonwealth ..

[The Natural Philosopher]

My first PC had an z80.

[meow2222]

If only. HDDs and SSDs fail to write buffer content to disc, resulting in the case of HDDs in occasional file corruption, and in the case of SSDs sometimes in massive multiple file corruption.

Why would that happen? I see little upside (filament lamp export), and an obvious downside (old appliances failing & frying).

NT

[Johny B Good]

====snip====

Very few are. Most are either 240v (UK) or else 220v (continental Europe).

Tungsten filament lamps designed for circa 230 volt are so senstive to mains voltage variations in regard of life and luminous efficacy, that they're manufactured to a much tighter voltage tolerance than anything else used on domestic mains voltage supplies. This leads to the lamps being manufactured to match the local mains voltage of the region they're intended to supply.