On Friday, June 10, 2011 11:49:22 AM UTC-7, Jon Elson wrote:
On 06/10/2011 02:25 AM, whit3rd wrote:

It isn't about battery charging; when the gizmo is plugged in, there's
a STANDBY power source (always-on) that might (or might not)
take the load off the battery.

No, I have never seen a system where the CMOS memory was supported by
the backup power supply.

Most Macintosh computers from mid-nineties through 2005 worked
that way; don't know for sure about the latest ones. A dead clock
battery didn't reset or lose anything until you unplugged your iMac.

On 2011-06-10, whit3rd wrote:
On Friday, June 10, 2011 11:49:22 AM UTC-7, Jon Elson wrote:
On 06/10/2011 02:25 AM, whit3rd wrote:

It isn't about battery charging; when the gizmo is plugged in, there's
a STANDBY power source (always-on) that might (or might not)
take the load off the battery.

No, I have never seen a system where the CMOS memory was supported by
the backup power supply.

Most Macintosh computers from mid-nineties through 2005 worked
that way; don't know for sure about the latest ones. A dead clock
battery didn't reset or lose anything until you unplugged your iMac.

Essentially -- any computer with a "soft" power switch will have
*some* power as long as the cord is plugged into an active outlet. A
soft power switch lets you turn power on and off with the same button,
with very little force. When turning *on*, it powers up the rest of the
outputs of the power supply. When turning *off* it signals the computer
to shut down cleanly, and then turns off the main outputs from the power
supply.

The power supplies for the ATX style systems are equipped for
this. Older systems simply had a power switch between the incoming
line power and the power supply, so you had to shut the computer down
yourself prior to shutting off the power.

The first machine which *I* had with this feature was the
Textronix 6130 -- a small unix box. It looks as though it came from
early 1985. Mine was acquired non-functional -- and it turned out to be
a fuse hidden inside the power supply. Once I replaced that, it worked
fine. I'm very glad that it had that feature, however, because
otherwise, until I had discovered the root password on it, I would not
have been able to shut it down cleanly.

Enjoy,
DoN.

--
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I miss the real switches.

One problem with soft switches / machines - they are always on.
That puts them in line with power line issues. A switch is a form
of isolation that helps keep some of the bad voltages away.

It also burns power when off. But that is another issue.

Martin

On 6/11/2011 7:56 PM, DoN. Nichols wrote:
On 2011-06-10, wrote:
On Friday, June 10, 2011 11:49:22 AM UTC-7, Jon Elson wrote:
On 06/10/2011 02:25 AM, whit3rd wrote:

It isn't about battery charging; when the gizmo is plugged in, there's
a STANDBY power source (always-on) that might (or might not)
take the load off the battery.

No, I have never seen a system where the CMOS memory was supported by
the backup power supply.

Most Macintosh computers from mid-nineties through 2005 worked
that way; don't know for sure about the latest ones. A dead clock
battery didn't reset or lose anything until you unplugged your iMac.

Essentially -- any computer with a "soft" power switch will have
*some* power as long as the cord is plugged into an active outlet. A
soft power switch lets you turn power on and off with the same button,
with very little force. When turning *on*, it powers up the rest of the
outputs of the power supply. When turning *off* it signals the computer
to shut down cleanly, and then turns off the main outputs from the power
supply.

The power supplies for the ATX style systems are equipped for
this. Older systems simply had a power switch between the incoming
line power and the power supply, so you had to shut the computer down
yourself prior to shutting off the power.

The first machine which *I* had with this feature was the
Textronix 6130 -- a small unix box. It looks as though it came from
early 1985. Mine was acquired non-functional -- and it turned out to be
a fuse hidden inside the power supply. Once I replaced that, it worked
fine. I'm very glad that it had that feature, however, because
otherwise, until I had discovered the root password on it, I would not
have been able to shut it down cleanly.

Enjoy,
DoN.