Very Computer

Hi there:

  Quick question. I have a tower desktop, not a laptop. I want to keep my
  hard drive running at all times when the system is up, but when I do
  "shutdown -p now,"  I want to use apm to first turn off the hard drive and
  then the whole system. I posted a similar question few days ago, but I am
  not sure whether apm automatically turns everything off when idle. I want
  to be sure what apm does before I recompile another kernel.

  Thanks for any suggestions.

  vector sigma

I'm curious as to why you would want to do this - eg turn off drive
and then system.  What is to be gained.

I can also see that if you attempted to turn the drive off before
all the sync'ing was done you could have a potential problem on
reboot.

This is more of a curiosity question than anything else.

Quote:> I posted a similar question few days ago, but I am not sure
> whether apm automatically turns everything off when idle.
> I want to be sure what apm does before I recompile another
> kernel.

I don't run APM but I have heard of others on other OSes that have
had power with APM shutting off the drive when the Unix kernel
wants to make it's normal updates.

Bill
--

Not really.  Spinning a normal hard drive up and down puts a lot of wear on
the bearing and costs a lot of energy.  (Laptop hard drives are much smaller
and have less rotational inertia, so they handle power-cycles with less
overhead.)

-Chuck

       -------------+-------------------+-----------------------------------
       "The human race's favorite method for being in control of the facts
        is to ignore them."  -Celia Green

Quote:> I'm curious as to why you would want to do this - eg turn off drive
> and then system.  What is to be gained.

I just thought that having the kernel shut off the hard drive and the system
is safer than having me manually press the power button to shut off
everything, and I was trying to prevent myself from damaging the hardware.

Do people normally have to manually turn off their Unix machines or leave it
to the OS?

vector sigma

Quote:> but if you are doing 'shutdown -p now' then the system will go into
> "stand-by" and turn off completely (including _everything_).

Not quite: when I do that, the system halts and becomes unresponsive, but
the power is still on and the hard drive still spins. I want the kernel to
turn off the power when I do "shutdown -p now"

vector

Ah.  What you should do is 'halt' the system and wait a few seconds while it
closes all running processes and flushes memory to disk, and then you can
power off the system safely.

Quote:> Do people normally have to manually turn off their Unix machines or leave it
> to the OS?

I have APM enabled and I have the OS power-off the hardware.

-Chuck

       -------------+-------------------+-----------------------------------
       "The human race's favorite method for being in control of the facts
        is to ignore them."  -Celia Green

Thank you  all, FreeBSD people. I am able to power off my computer with
kernel now. This all I did (in case anyone else needs to know what to do):

1. I have a desktop tower, not a laptop, and my motherboard BIOS supports
apm.
2. In kernel, I added: "device apm0"
3. make device "/dev/MAKEDEV apm"
4. in /etc/rc.conf, I added "apm_enable="YES" "
5. command "shutdown -p now" will turn off harddrive and power.

Once again, thank you all.

vector sigma

Before *tron was, I was.

When I have to turn them off I do it myself.  However I try not to
turn them off - ever.  The machine that preceded this one stayed up
24x7x365 until the disk controller finally went [it could have been
the drive but it acted more like the controller which was not
replaceable then].  So that was 7 years 2 months and a few days
of always being on.

--

Use 'shutdown' and not 'halt'. Even though the 'halt' is supposed
to flush everything properly in BSD it doesn't always work that
cleanly in other OSes so shutdown is good habit to get into.

--

A point.  On some SysV systems, you want to invoke shutdown or telinit to
switch to the appropriate runlevel, which will run various /etc/init.d scripts
to stop running services, and then sync and halt the system.

By comparison, FreeBSD and many other BSD-derived systems simply do a kill
-TERM, kill -9, which doesn't always shut down complex systems like a database
very cleanly, either.

-Chuck

       -------------+-------------------+----4-------------------------------
       "The human race's favorite method for being in control of the facts
        is to ignore them."  -Celia Green

Yes, but at least that is a two stage process.   One is a 'clean up your mess or
you'll get killed', and the next (later on), the process will be forced down.   Ill
conceived of applications (those which are supposed to be reliable) forget to
catch the signals, and have serious ramifications on shutdowns.

John

And that works very well when processes are written properly and do not have
external dependencies.  Software ported from non-Unix systems, software
running in an interpreter (like a Java VM, perhaps), and software with complex
dependencies between multiple processes tend to not do so well.

For example, even if each and every Oracle process handled kill -TERM
properly, having your transaction log writer process shutdown cleanly before
various other database processes do doesn't result in Oracle closing and
dismounting the databases cleanly.

-Chuck

       -------------+-------------------+-----------------------------------
       "The human race's favorite method for being in control of the facts
        is to ignore them."  -Celia Green

On Mon, 16 Sep 2002 20:12:48 +0000 (UTC)

CS> By comparison, FreeBSD and many other BSD-derived systems simply do a
CS> kill-TERM, kill -9, which doesn't always shut down complex systems
CS> like a database very cleanly, either.

        The rc.shutdown script is a little more sophisticated than that,
among other things it runs the scripts in the various rc.d directories
with "stop" as the  argument. The killing starts after everything has
been asked nicely to stop :) See man rc for further details.

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