On Tue, 28 Aug 2012 20:28:07 +0100 (BST), ard at p850ug1.demon.co.uk (Tony
> Of course wall-warts are country specfic in that the mains voltage and
> conenctor are different in differnet countries. So I've probably never
> seen a modern one intended for use in the USA and thus UL listed
> But the ones we get over here have no protective devices at all. No fuse,
> no thermal fuse. If you are lucky, the resistors in a swithc-mode wall
> wart are fusible, flameproof types. Most of the time they are not.
In Europe, mains devices have to be CE-certified and display the CE mark.
But the manufacturers certify themselves that their products are
compatible with the regulations, nobody actually tests them unless it is
necessary to prove that they do not comply, e.g. if a competitor reports
them to the authorities as being non-compatible, or they are suspected
of being the cause of an accident, or they are suspected of being fake.
Devices made in China may show the "China Export" symbol, which is very
like the CE mark and may be easily confused with it (= is meant to be
confused with it?) http://www.icqc.co.uk/en/china-export.php but does
not mean that the device complies with EU regulations.
> For linear wall-warts, the transformer primary is _supposed_
> to burn out in a safe manner if the thing is overloaded. My
> (accindental) experience is that they do not. The transformer
> can get hot enough to soften the plastic case, but it does not burn out.
I thought that many (most?) wall warts were "impedance protected". i.e. the winding resistance + inductance of the device is set such that thing might get hot and buzz in a short circuit but will not catch on fire. Like those small AC motor windings.
Some folks think UL rating means that the device is reliable, or well engineered in some hypothetical sense, but really what it means is that it won't start a fire.
Impedance protection is one of the reasons why unregulated wall warts have such high delta between loaded and unloaded voltage (often as much as a factor of two). They are designed with high internal resistance to provide the impedance protection.
Hardly Apple I territory, but 1,100.00 GBP (~ 1700 USD) is an incredible
amount for a home computer which occupied the middle ground: not as
ubiquitous or famous as the Spectrum, C64, BBC micro etc., but not as rare
or desirable as those which came before it (ZX80, Acorn System 1 etc.)
It's not as though it's an early release or one of the ones sold in kit
form. The lack of serial number on the case raises the possibility that the
case and PCB weren't paired at the factory (which surely makes it
non-original and a mongrel :-)
I can't even begin to make sense of most ebay sales, but what do people
think? Just someone with rather deep pockets? Or perhaps the seller buying
it back themselves in order to create an inflated sense of 'market value'
(and with the intention of re-listing it under a different account in a few
On 8/27/12 10:00 AM, cctech-request at classiccmp.org wrote:
> On Mon, 27 Aug 2012, Jim Brain wrote:
>> >Can you cite some sources for this position? Sources I have note that
>> >Patterson wrote a new OS to go with the Seattle Computer Products 8086
>> >kit and used CP/Ms API to aid in porting apps, but the internals were
>> >significantly different. If true, I'm not sure I'd call that a "port".
>> >If so, then Linux is a "port" of BSD or ATT UNIX.
> I will concede that "port" is a poor choice of terms.
> Patterson wrote it as a placeholder. The intent was that they would go to
> CP/M-86 when that was ready, and QDOS ("Quick and Dirty Operating System")
> was intended as a temporary substitute until then. So, I'm hesitant to
> call it a "new OS"
Could you at least spell Tim's last name correctly? It is 'Paterson'.
And a recent code analysis indicates that QDOS was not stolen from CP/M -
If he didn't copy it from CP/M, why isn't it a "new OS"?
For those who are in an exploring mindset, try
'telnet nexus-core.xs4all.nl 10001'
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Zeg NEE tegen de 'slimme' meter.