Hi.


>...
>> Please can someone explain the difference between
>> shutting off a computer using the power switch, then
>> turning it back on, compared to pressing the reset
>> switch?
>
>If memory serves correctly, it is because of capacitance.
When you
>perform a reset, it causes the machine to go through it's
boot sequence
>just as if the power had been turned on with the exception
of the state
>of the memory.  Whatever is in memory MAY remain there,
thus it is in an
>indeterminate state.  Data, program fragments, whatever.


Bios memory test surely leaves memory contents as 00.
Ctrl+Alt+Del skips memory test.

>
>> I read that if you shut the computer off, you should
>> wait about a half a minute before turning it back
>> on. I don't know if this is outdated info, and I
>
>When the power is removed and left off for 10 seconds or
more (cycling
>power), then any residual electical charges left on the
motherboard,
>memory or peripheral cards are allowed to bleed off thus
leaving
>everything in a known default power off state.
>

The time is to make sure that /Reset signal starts at 0V.
Indeed, perhaps it is not enough for all capacitors to
discharge, which, btw, would shorten their life.

>As the machine reboots it uses various areas of memory.
Some software
>will initialize the memory it uses to a known state and
other software
>will not.  If the memory is NOT initialized to a known
state and the
>software just uses the values it finds there, then the
program's actions
>will be unpredictable.  It would depend on how the software
is written.
>I don't know how much system software or other software you
use at
>startup is written in this way, but it would make a
difference.
>
>This is the way that I learned this stuff a while back.
This is
>certainly not a technically accurate explanation and I
don't know how
>much of it still applies.  But since this is the kind of
advice I still
>get from tech support lines (cycling power as opposed to
resetting), I
>assume it still holds true.  If anyone has a clearer, more
accurate
>explanation, PLEASE correct me!
>...


Reset button is much preferable to cycling power. If you
cycle power, you are going to stop and then restart disk
movement, which is not very convenient. Also, possibly the
transient currents on the AC side and on the switching
electronic components of the PC power supply, the monitor
supply, etc, will be huge if you cycle. You would be
frightened of currents (amps) magnitude seeing simulations
of a switching supply turning on.

>--
>Larry Atlow
Internet:[log in to unmask]
>Microcomputer Analyst                Phonenet: (601)
264-9639
************************************
Javier Vizcaino. Ability Electronics. [log in to unmask]
http://www.automodelismo.com http://ability53.hypermart.net
  Starting point:        (-1)^(-1) = -1
  Applying logarithms: (-1)*ln(-1) = ln(-1)
  Since ln(-1) <> 0, dividing:  -1 = 1     (ln(-1) is
complex, but exists)

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