mesp@cc.newcastle.edu.au (Simon Plint) (02/20/91)
I talked to the head technician at my local Apple retailer about leaving the Mac on. His reply was that when he was in the Air Force they conducted tests on electronics and found that they had far less faults with the equipment that had been left on. As for myself I am responsible for 5 SE/30s that were bought, new, six months ago and have been running ever since. I have had to replace 2 analog brds and 1 int disc drive. These faults occured within the first month. ------------------------- Simon Plint TUNRA BSH University of Newcastle, N.S.W. AUSTRALIA. _________________________
hamilton@kickapoo.cs.iastate.edu (Jon Hamilton) (02/24/91)
John_Richard_Bruni@cup.portal.com writes: >I seem to recall the latest monthly bulletin from the Rocky Mountain Institute >saying that the power usage of the average home computer, whatever that is, >puts two tons of extra CO2 in the air per year if left on all the time rather >than turning it on when needed. I guess the question of `leave it on?` must >also examine the issue of whether the extra power use & subsequent pollution >is outweighed by the longer lifespan of the equipment when left on. If, >indeed, leaving one`s computer on does result in longer MTBF, then one needs >to know how much pollution is eliminated by not having to use more energy and >resources to build more computers. Is the power wastage outweighed by savings >in energy/resource usage? Of course, anything that uses power can be looked >at in this manner. This is an old topic that doesn't appear to be likely to go away anytime soon. As has been pointed out already, in the winter, that energy mainly puts heat into the room (there just ain't that many moving parts in a computer). If the computer is keeping the furnace from running as much as usual, then you've got another variable to consider. I leave mine on for several reasons: increased MTBF, heat generation (we have an electric furnace, so it's about the same efficiency), and I don't like waiting for my machine to boot every time I want to use it. UNIX filesystems are much nicer (less fragmented) when you leave the machine on and idle for a while. -- % Internet : hamilton@kickapoo.cs.iastate.edu | Insert cute and/or % % America Online : JonHam | deeply meaningful % % Elsewhere : ThatGeek@his.little.corner | musical quote here %
hamilton@kickapoo.cs.iastate.edu (Jon Hamilton) (02/25/91)
wnn@ornl.gov writes: >In article <hamilton.667347740@kickapoo.cs.iastate.edu> >hamilton@kickapoo.cs.iastate.edu (Jon Hamilton) writes: [...] >Dismal efficiency! Regardless of how many moving parts there are, it all ends >up as heat. >Using a heating system that directly converts high-enthalpy electricity to >low-enthalpy heat is not a wise use of energy and is not a good excuse for >doing the same thing with a computer. Are you willing to you turn your's off at >least outside the heating season? No I am not. [...] >I turn my Mac on as soon as I arrive at the office. By the time I have taken >off my coat and settled down, it usually is ready. It takes me about 5 mins to boot A/UX and check all my file systems. I just won't do this every time I want to use the machine while I have an alternative. I can understand an argument for shutting the machine off at night when in bed, but I'm not the only one who uses my machine, and sometimes people are on doing things at odd hours of the night. >>UNIX filesystems are much nicer (less fragmented) when >>you leave the machine on and idle for a while. >File system maintenance does not require over one hundred hours per week! You >can configure your UNIX system to do it as part of the shutdown script. For >MultiFinder users, it is beneficial to boot daily because it eliminates memory >fragmentation. I have noticed that weird software problems, probably >attributable to minor corruption of the System Heap, are more commonly >experienced by users who leave their computers on all the time. When you power >on in the morning you get a clean slate. I reboot about once a week most of the time. I don't have any problem with you or anybody else shutting their computer off daily. Anyone who does so hourly I would question. I leave mine on. If you want to power yours down, fine. I'm not telling you to do otherwise. I was simply attempting to point out that there's more to consider than whether the hard drive(s) will last longer when determining a power routine for your machine. >Wolfgang N. Naegeli >University of Tennessee & Oak Ridge National Laboratory >Internet: wnn@ornl.gov Bitnet: wnn@ornlstc >Phone: 615-574-6143 Fax: 615-574-6141 (MacFax) >QuickMail (QM-QM): Wolfgang Naegeli @ 615-574-4510 -- % Internet : hamilton@kickapoo.cs.iastate.edu | Insert cute and/or % % America Online : JonHam | deeply meaningful % % Elsewhere : ThatGeek@his.little.corner | musical quote here %
yee@osf.org (Michael K. Yee) (02/26/91)
In article <hamilton.667347740@kickapoo.cs.iastate.edu> hamilton@kickapoo.cs.iastate.edu (Jon Hamilton) writes: > John_Richard_Bruni@cup.portal.com writes: >> If, indeed, leaving one`s computer on does result in longer MTBF, then one ^^^^^^^^^^^ >> needs to know how much pollution is eliminated by not having to use more >> energy and resources to build more computers. ... > got another variable to consider. I leave mine on for several reasons: > increased MTBF, heat generation (we have an electric furnace, so it's about ^^^^^^^^^^^^^^ > the same efficiency), and I don't like waiting for my machine to boot every > time I want to use it. UNIX filesystems are much nicer (less fragmented) when > you leave the machine on and idle for a while. I like to know how MTBF (mean time between failure) is INCREASED by leaving a hard drive on? Isn't MTBF expressed in hours? So it should follow that the less time you have the drive on, the longer it should last, right? What am I missing here? Is there an implied reduction in MTBF each time I cycle power on a drive (i.e. minus NN% MTBF per power cycle)? BTW: Why would a UNIX filesystems automagically become less fragmented if you leave the machine idling? No file access happens when the system is "idle". Does A/UX automatically do hard disk optimization when the system is idle? =Mike -- = Michael K. Yee -- yee@osf.org or uunet!osf.org!yee -- = OSF/Motif Development = "I can't give you brains, but I can give you a diploma." -- The Wizard of OZ
hamilton@kickapoo.cs.iastate.edu (Jon Hamilton) (02/26/91)
yee@osf.org (Michael K. Yee) writes: >In article <hamilton.667347740@kickapoo.cs.iastate.edu> hamilton@kickapoo.cs.iastate.edu (Jon Hamilton) writes: >> John_Richard_Bruni@cup.portal.com writes: > I like to know how MTBF (mean time between failure) is INCREASED by > leaving a hard drive on? Isn't MTBF expressed in hours? So it > should follow that the less time you have the drive on, the longer > it should last, right? What am I missing here? Is there an implied > reduction in MTBF each time I cycle power on a drive (i.e. minus NN% > MTBF per power cycle)? Hard drives, like most computer equipment, undergo more stress when powering on and warming up than if left running. > BTW: Why would a UNIX filesystems automagically become less > fragmented if you leave the machine idling? No file access happens > when the system is "idle". Does A/UX automatically do hard disk > optimization when the system is idle? most unixes (at least most with ufs) defragment the disk when there's little or no file access going on. Some more often than others, but it is a common feature. > =Mike >-- >= Michael K. Yee -- yee@osf.org or uunet!osf.org!yee -- >= OSF/Motif Development >= "I can't give you brains, but I can give you a diploma." -- The Wizard of OZ -- % Internet : hamilton@kickapoo.cs.iastate.edu | Insert cute and/or % % America Online : JonHam | deeply meaningful % % Elsewhere : ThatGeek@his.little.corner | musical quote here %
wnn@ornl.gov (02/28/91)
In article <hamilton.667519535@kickapoo.cs.iastate.edu> hamilton@kickapoo.cs.iastate.edu (Jon Hamilton) writes: >yee@osf.org (Michael K. Yee) writes: > >>In article <hamilton.667347740@kickapoo.cs.iastate.edu> hamilton@kickapoo.cs.iastate.edu (Jon Hamilton) writes: >>> John_Richard_Bruni@cup.portal.com writes: > > >> I like to know how MTBF (mean time between failure) is INCREASED by >> leaving a hard drive on? Isn't MTBF expressed in hours? So it >> should follow that the less time you have the drive on, the longer >> it should last, right? What am I missing here? Is there an implied >> reduction in MTBF each time I cycle power on a drive (i.e. minus NN% >> MTBF per power cycle)? > >Hard drives, like most computer equipment, undergo more stress when powering >on and warming up than if left running. True, but where is the cut-over? It appears that in normal use, i.e. not being turned on and off a dozen times or more per day, operating time is the more important factor. Otherwise, the equipment would probably be rated in MPCBF (Mean power-on cycles before failure). Why would cost-conscious manufacturers bother to build in a power switch if they expected the customer to leave the equipment powered on all the time? Also, I have yet to read a computer manual that recommends to leave the power on, though most of them talk about shutdown procedures. Not even for the MacPlus, which has been prone to power-supply-circuitry failure, did Apple Computer recommend leaving it on. Wolfgang N. Naegeli University of Tennessee & Oak Ridge National Laboratory Internet: wnn@ornl.gov Bitnet: wnn@ornlstc Phone: 615-574-6143 Fax: 615-574-6141 (MacFax) QuickMail (QM-QM): Wolfgang Naegeli @ 615-574-4510
carter@cat27.cs.wisc.edu (Gregory Carter) (03/03/91)
John_Richard_Bruni@cup.portal.com writes:
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I seem to recall the latest monthly bulletin from the Rocky Mountain Institute
saying that the power usage of the average home computer, whatever that is,
puts two tons of extra CO2 in the air per year if left on all the time rather
than turning it on when needed. I guess the question of `leave it on?` must
also examine the issue of whether the extra power use & subsequent pollution
is outweighed by the longer lifespan of the equipment when left on. If,
indeed, leaving one`s computer on does result in longer MTBF, then one needs
to know how much pollution is eliminated by not having to use more energy and
resources to build more computers. Is the power wastage outweighed by savings
in energy/resource usage? Of course, anything that uses power can be looked
at in this manner.
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Well thats nothing, I heard leaving on your mac all the time can cause
the sun to shine upside down and the moon to fall from the sky. Obviously,
more reporting is needed before it can be confirmed, but a recent women
in Skogie, Illonois swears she had the moon in her backyard when she forgot
to turn off her Mac PLUS. After doing so the moon resumed proper orbit.
--Gregory
PS: Oh yeah, leaving on your Mac can also cause extreme bandwidth usage on
internet too.