Re: shutdown on BSD and Linux
Rahul Siddharthan wrote: x I tried upstart on my laptop and got the fastest console login I have ever seen: within a couple of seconds of the kernel loading, I could log in to my home directory, even as it continued to probe other hardware, connect to the network, etc. The graphical login (kdm in my case) takes much longer, I think about as long as with old-fashioned init. This is because Linux lies about kernel loading. When kernel boots it has so little functions that you have the impression it is very fast. But all the hardware drivers are loaded after, when init launches hardware detection and kernel modules loading. It is all those hardware probes which take time when (free|dragon)bsd load. I am puzzled hat nobody mentions the most widely used OS which has parallel boot, it is WindowsXP. On my machine which triple boots Windows, BSD and Linux, it is Windows which boots faster by fast, in fact it takes half the time of unices to be in graphical mode able to use the machine. But it is clear that at this moment Windows is still loading stuff, and if you wait that everything is loaded it takes far longer to boot than any unix. On my machine, Ubuntu takes around the same time as FreeBSD to boot, faster than the Linux distro i had previously (Debian Sarge). Rahul -- Michel Talon
Re: shutdown on BSD and Linux
[EMAIL PROTECTED] wrote: I am puzzled hat nobody mentions the most widely used OS which has parallel boot, it is WindowsXP. On my machine which triple boots Windows, BSD and Linux, it is Windows which boots faster by fast, in fact it takes half the time of unices to be in graphical mode able to use the machine. But it is clear that at this moment Windows is still loading stuff, and if you wait that everything is loaded it takes far longer to boot than any unix. Haha, MS wants to make people believe that boot time == time between turning on the computer and logging in. I love their propaganda, very funny indeed. I am not an anti-MS guy, just could not keep this to myself. :-)
Re: shutdown on BSD and Linux
Rahul Siddharthan [EMAIL PROTECTED] wrote: I've long had a question on the shutdown process. Linux systems run a separate shutdown script for every process that was started at boot, and can take a minute or two to shutdown. FreeBSD and Dragonfly, as far as I can tell, just kill all processes, flush buffers, unmount filesystems and shutdown/poweroff, which takes about 5 seconds. It also executes stop-scripts, depending on which kind of applications you are using. For example, the PostgreSQL database installs a script in /usr/local/etc/rc.d that is used to start or stop the service. That's because it is important to stop the database cleanly instead of just blindly killing the process (although Postgres is pretty robust in that regard and usually survives all such evil things). However, not all applications and services require a script for stopping. In particular, the daemon processes in the base system (syslog, cron etc.) don't need any special actions, so it's sufficient to catch them with the final SIGTERM that init(8) broadcasts to all processes (followed by SIGKILL for those processes that ignored it). Also, BSD traditionally doesn't umount file systems or takes network interfaces down upon a shutdown, so there's no need to run stop scripts for those, either. All of that saves a lot of time. So what's up? Is BSD-style shutdown dangerous, or are the Linux people stupid? Neither nor. BSD and Linux have very different init/rc implmentations. Linux has a SysV-style runlevel implementation (similar to Solaris), which means that certain scripts get executed whenever the system enters a different runlevel. A shut- down is a separate runlevel, too, so it executes scripts to cleanly shutdown daemons etc. In Linux, every little fart has its own script with a considerable overhead, and they are quite verbose. The BSD world traditionally doesn't have such a system of runlevels. Nevertheless, when you use shutdown(8), scripts from /usr/local/etc/rc.d/* are executed with an argument of stop (DragonFly has inherited that feature from FreeBSD). Meanwhile, FreeBSD has implemented a system called rcNG which also seperates out most parts of the traditional BSD- style /etc/rc into many small start/stop scripts in the /etc/rc.d directory. DF has also taken that from FreeBSD. BTW - the poweroff on my laptop, with Dragonfly and FreeBSD (last I checked), is also accompanied by a rather alarming and short-lived whine, as if a spinning disk or fan was suddenly stopped. I don't get this sound with linux or windows. Could that be the CD/DVD drive? Best regards Oliver -- Oliver Fromme, secnetix GmbH Co. KG, Marktplatz 29, 85567 Grafing Dienstleistungen mit Schwerpunkt FreeBSD: http://www.secnetix.de/bsd Any opinions expressed in this message may be personal to the author and may not necessarily reflect the opinions of secnetix in any way.
Re: shutdown on BSD and Linux
Rahul Siddharthan wrote: I've long had a question on the shutdown process. Linux systems run a separate shutdown script for every process that was started at boot, and can take a minute or two to shutdown. FreeBSD and Dragonfly, as far as I can tell, just kill all processes, flush buffers, unmount filesystems and shutdown/poweroff, which takes about 5 seconds. It may be faster on *BSD, but no more 'rude', at least with shutdown now. Each process is asked politely to terminate - per the information in ~/etc/rc and ~/etc/rc.d Only if they dally do they get a firmer reproach. Init 6 is *slightly* less forgiving, it goes directly to *dammit, I mean NOW* mode. No daemon I have run in the last 6+ years was ever bothered by that. OTOH, we use softupdates, RAID1, and forced '-y' not 'p' fscking at boot-time... So what's up? Is BSD-style shutdown dangerous, - not in the least! or are the Linux people stupid? Surely you didn't even need to *ask* that in the face of massive evidence? More 'gently' - *BSD has always been far more coherent, hence more efficient at managing resources. It is also less frequently asked to do dumb Microsoftish-things than Linux. The question came to my mind again when I saw Ubuntu's specification for shutdown in their future versions: https://wiki.ubuntu.com/Teardown Basically, it says the majority of init scripts needn't be called at shutdown because the processes can just be sent signals and trusted to do the right thing. However, some controlled shutdowns *do* need to be done. Why can the BSDs get away with not doing these controlled shutdowns? Because the *BSD's are complete *Operating Systems* - with a very long history of refinement as well as imrovement. Linux is not an Operatign System, and has a shorter, and spottier, history - one with far less strictness in QC. Linux is a 'kernel', hooked - more or less successfully - to a diverse collection of 'GNU' kit that makes it possible to *emulate* an operating system. Thus the 300+ 'distros' out there in Penguin-land. A *BSD variant is NOT a 'distro'. It is developed and tested as a whole-cloth exercise. Th core components are know in advance, and tested together. Think of *BSD as the refined 'whole system' characteristic of a Mercedes - auto or truck. Linux, by comparison, is any of a brazillion varieties of garage-built hot-rod - motorcycle to 'bigfoot' pickup truck - kitted together out of whatever bits of kit the 'distro' packagers happens to hold in high regard. Obviously, some 'garages' are bigger, better funded, and more competant than others. That doesn't mean you can't put together a very good Linux, managed by an expert operator. It DOES mean that there is an element of chance. Distro's aside, Linux' Kernel is nothing to write home about, either, so it is starting off handicapped. But it is free and available, and 'has lots of drivers...' so... BTW - the poweroff on my laptop, with Dragonfly and FreeBSD (last I checked), is also accompanied by a rather alarming and short-lived whine, as if a spinning disk or fan was suddenly stopped. I don't get this sound with linux or windows. Rahul Sounds more like a CPU-fan or HDD spun UP, not down, as needed in a burst of intensive activity (putting stuff away properly before shutdown..) Bill
Re: shutdown on BSD and Linux
On Thu, Sep 07, 2006 at 10:28:44AM +, Rahul Siddharthan wrote: I've long had a question on the shutdown process. Linux systems run a separate shutdown script for every process that was started at boot, and can take a minute or two to shutdown. FreeBSD and Dragonfly, as far as I can tell, just kill all processes, flush buffers, unmount filesystems and shutdown/poweroff, which takes about 5 seconds. If you use shutdown to reboot, it runs the scripts from /etc/rc.d as well, but most simply don't do anything. Joerg
Re: shutdown on BSD and Linux
Bill Hacker wrote: Rahul Siddharthan wrote: The question came to my mind again when I saw Ubuntu's specification for shutdown in their future versions: https://wiki.ubuntu.com/Teardown Basically, it says the majority of init scripts needn't be called at shutdown because the processes can just be sent signals and trusted to do the right thing. However, some controlled shutdowns *do* need to be done. Why can the BSDs get away with not doing these controlled shutdowns? Because the *BSD's are complete *Operating Systems* - with a very long history of refinement as well as imrovement. I don't see how that answers the question. A *BSD variant is NOT a 'distro'. It is developed and tested as a whole-cloth exercise. Th core components are know in advance, and tested together. If you include ports/pkgsrc, it IS a distro. And decidedly flaky, at that, compared to most linux distros. No BSD comes with Apache or PostgreSQL in the base system, and only NetBSD includes Postfix, to give the three examples in Ubuntu's teardown wiki article. Think of *BSD as the refined 'whole system' characteristic of a Mercedes - auto or truck. Linux, by comparison, is any of a brazillion varieties of garage-built hot-rod - motorcycle to 'bigfoot' pickup truck - kitted together out of whatever bits of kit the 'distro' packagers happens to hold in high regard. I'd have taken that seriously at one time -- in fact I did -- but one too many crashes that completely trashed my UFS+softupdates filesystem changed my mind. When I reported that on FreeBSD, the answer is yeah, ATA does write-caching and lies about it and sucks generally, tough, use SCSI. (And I'm not the only one to have had trashed filesystems, there are plenty of unexpected softupdates inconsistency errors reported on lists. Some bugs were found and fixed by Matt, IIRC, but it looks like only Kirk McKusick really understands softupdates.) Yes, I use cheap ATA hardware, and don't always notice when my laptop battery is going to die, and sometimes plug in unstable devices, so I have occasional crashes and unclean poweroffs. On Linux ext3, held in near-universal scorn by BSD types, I have NEVER had a trashed filesystem, and only ever lost data in a couple of open files (usually system logs). In fact, the only problem I ever remember having on linux is poor VM behaviour, exhibited when a runaway process eats all available RAM. And these days that's much better too. Distro's aside, Linux' Kernel is nothing to write home about, either, so it is starting off handicapped. It's way better than BSD kernels on modern hardware, that need to handle devices that may appear or disappear without notice -- USB, PCMCIA, firewire I have NEVER panicked a Linux system by removing a USB device, no matter whether it was in use or not. I can panic FreeBSD or Dragonfly in a few seconds that way. And if it doesn't panic immediately, it spews absurd messages about being unable to detach the device because it is in use, and then panics half an hour later. And, again, I'm not the only person to have seen this. In fact, I have only ever panicked a Linux system in years by using a ndiswrapper driver, and that too went away after I recompiled a kernel with 16K stack space (which Windows has and NDIS drivers assume). But it is free and available, and 'has lots of drivers...' .. and WORKS. BTW - the poweroff on my laptop, with Dragonfly and FreeBSD (last I checked), is also accompanied by a rather alarming and short-lived whine, as if a spinning disk or fan was suddenly stopped. I don't get this sound with linux or windows. Rahul Sounds more like a CPU-fan or HDD spun UP, not down, as needed in a burst of intensive activity (putting stuff away properly before shutdown..) Nope... if the burst of activity happens while (as I said) the machine is powering off, something is seriously amiss. On linux, the sounds die away and the machine is silent for a second or two BEFORE poweroff. Rahul
Re: shutdown on BSD and Linux
Joerg Sonnenberger wrote: On Thu, Sep 07, 2006 at 10:28:44AM +, Rahul Siddharthan wrote: I've long had a question on the shutdown process. Linux systems run a separate shutdown script for every process that was started at boot, and can take a minute or two to shutdown. FreeBSD and Dragonfly, as far as I can tell, just kill all processes, flush buffers, unmount filesystems and shutdown/poweroff, which takes about 5 seconds. If you use shutdown to reboot, it runs the scripts from /etc/rc.d as well, but most simply don't do anything. Thanks Joerg (and Oliver) for your answers. I'm still puzzled because in the linux case, too, most scripts don't do anything (or just send a signal). And the startup time for BSD is faster than Linux but not that much faster, compared to the shutdown time. If the fork/exec of a shell is what causes the overhead, then---for a similar number of scripts---the systems should take similar time to shutdown. Or maybe it's just that /bin/sh is much faster than /bin/bash... and startup has other overheads so it's not so noticeable. Rahul
Re: shutdown on BSD and Linux
On Thu, Sep 07, 2006 at 11:50:20AM +, Rahul Siddharthan wrote: If you include ports/pkgsrc, it IS a distro. And decidedly flaky, at that, compared to most linux distros. No BSD comes with Apache or PostgreSQL in the base system, and only NetBSD includes Postfix, to give the three examples in Ubuntu's teardown wiki article. OpenBSD has had Apache 1.3 in base for ages. Apache behaves graceful, as does PostgreSQL. In fact, even killing is not very problematic for both, as long as the disks are correctly flushed. Postfix doesn't really care either. I'd have taken that seriously at one time -- in fact I did -- but one too many crashes that completely trashed my UFS+softupdates filesystem changed my mind. When I reported that on FreeBSD, the answer is yeah, ATA does write-caching and lies about it and sucks generally, tough, use SCSI. (And I'm not the only one to have had trashed filesystems, there are plenty of unexpected softupdates inconsistency errors reported on lists. Some bugs were found and fixed by Matt, IIRC, but it looks like only Kirk McKusick really understands softupdates.) I know of one such issue (reference count of the root directory being sometimes wrong), but yes -- most of the issues are ATA write cache related. Yes, I use cheap ATA hardware, and don't always notice when my laptop battery is going to die, and sometimes plug in unstable devices, so I have occasional crashes and unclean poweroffs. On Linux ext3, held in near-universal scorn by BSD types, I have NEVER had a trashed filesystem, and only ever lost data in a couple of open files (usually system logs). In fact, the only problem I ever remember having on linux is poor VM behaviour, exhibited when a runaway process eats all available RAM. And these days that's much better too. I had a completely trashed ext3 once, on *SCSI* disks. ATA write caching with reordering can kill journaling as well, BTW. The chances are just smaller. Sounds more like a CPU-fan or HDD spun UP, not down, as needed in a burst of intensive activity (putting stuff away properly before shutdown..) Nope... if the burst of activity happens while (as I said) the machine is powering off, something is seriously amiss. On linux, the sounds die away and the machine is silent for a second or two BEFORE poweroff. It might issue a stop command to ATA drives before calling the powerdown function. Not sure. But drives are supposed to handle that themselve and almost all do. Joerg
Re: shutdown on BSD and Linux
Just to clarify, the rc.shutdown script uses rcorder with the -k shutdown option for /etc/rc.d/*. pkgbox:/home/reed grep 'KEYWORD.*shutdown' /etc/rc.d/* /etc/rc.d/cron:# KEYWORD: shutdown /etc/rc.d/inetd:# KEYWORD: shutdown /etc/rc.d/ipfs:# KEYWORD: shutdown /etc/rc.d/local:# KEYWORD: shutdown /etc/rc.d/localdaemons:# KEYWORD: shutdown /etc/rc.d/mixer:# KEYWORD: shutdown /etc/rc.d/nfsclient:# KEYWORD: shutdown /etc/rc.d/random:# KEYWORD: shutdown /etc/rc.d/swap1:# KEYWORD: shutdown pkgbox:/home/reed rcorder -k shutdown /etc/rc.d/* /etc/rc.d/swap1 /etc/rc.d/random /etc/rc.d/ipfs /etc/rc.d/nfsclient /etc/rc.d/local /etc/rc.d/mixer /etc/rc.d/cron /etc/rc.d/localdaemons /etc/rc.d/inetd It does the above in reverse order runs each with stop. Note that the /etc/rc.d/localdaemons above handles the local_startup (/usr/pkg/etc/rc.d /usr/local/etc/rc.d /usr/X11R6/etc/rc.d) directories -- but it doesn't use rcorder for them even though it probably should also to take advantage of # KEYWORD: shutdown also from the scripts from pkgsrc.
Re: shutdown on BSD and Linux
On 2006-09-07 17:50, Justin C. Sherrill wrote: On Thu, September 7, 2006 6:28 am, Rahul Siddharthan wrote: BTW - the poweroff on my laptop, with Dragonfly and FreeBSD (last I checked), is also accompanied by a rather alarming and short-lived whine, as if a spinning disk or fan was suddenly stopped. I don't get this sound with linux or windows. I had an older system that would do this with the fans; I never saw a negative effect. I assumed it was some setting that was tripped as systems were shutdown, which made the fans react as if the temperature was too high - perhaps the equivalent of a burst of static. I have a computer on which the fan-controls does not start working until somewhere post BIOS, before that they run for full. Might be something like that but in reverse, the fan-control is disabled and the fans run for full by default. How does the computer sound when it starts? -- Erik Wikström
Re: shutdown on BSD and Linux
On 07-09-2006, Erik Wikstr�m [EMAIL PROTECTED] wrote : On 2006-09-07 17:50, Justin C. Sherrill wrote: On Thu, September 7, 2006 6:28 am, Rahul Siddharthan wrote: I had an older system that would do this with the fans; I never saw a negative effect. I assumed it was some setting that was tripped as systems were shutdown, which made the fans react as if the temperature was too high - perhaps the equivalent of a burst of static. I have a computer on which the fan-controls does not start working until somewhere post BIOS, before that they run for full. Might be something like that but in reverse, the fan-control is disabled and the fans run for full by default. How does the computer sound when it starts? Could it be ACPI tearing down ? I've got no clue, but my Compaq Presario also exhibits that behaviour. Francis
Re: shutdown on BSD and Linux
On 2006-09-07 18:46, Oliver Fromme wrote: PS: By the way, recently someone suggested in a FreeBSD mailing list that start scripts could be run in parallel if they don't depend on each other (which rcorder(8) can easily find out). It would probably speed up booting. However, I don't know if anyone is actually working on implementing that. I seem to recall that it was suggested for inclusion in DFly too but the consensus of the developers were that boot-time is not important enough to use a potentially dangerous method. Not that anyone thought it to be especially dangerous but nor was it worth the effort. The reasoning was that DFly would most likely be used on servers which are normally not booted that often, however as I run it on my laptop I wouldn't mind a faster boot :-) -- Erik Wikström
Re: shutdown on BSD and Linux
On Thu, September 7, 2006 12:46 pm, Oliver Fromme wrote: PS: By the way, recently someone suggested in a FreeBSD mailing list that start scripts could be run in parallel if they don't depend on each other (which rcorder(8) can easily find out). It would probably speed up booting. However, I don't know if anyone is actually working on implementing that. As I recall, Apple's launchd is a replacement for rc (and init and inetd), and runs in parallel. (My Mac does start up very fast indeed, though launchd is not the only reason) http://developer.apple.com/documentation/Darwin/Reference/ManPages/man8/launchd.8.html There is/was a SoC project for bringing it to FreeBSD: http://wikitest.freebsd.org/launchd It'd be neat to have in DragonFly, though it would appear to require some quantity of work.
Re: shutdown on BSD and Linux
On Thu, Sep 07, 2006 at 07:35:24PM +0200, Erik Wikström wrote: On 2006-09-07 18:46, Oliver Fromme wrote: PS: By the way, recently someone suggested in a FreeBSD mailing list that start scripts could be run in parallel if they don't depend on each other (which rcorder(8) can easily find out). It would probably speed up booting. However, I don't know if anyone is actually working on implementing that. I seem to recall that it was suggested for inclusion in DFly too but the consensus of the developers were that boot-time is not important enough to use a potentially dangerous method. Not that anyone thought it to be especially dangerous but nor was it worth the effort. The reasoning was that DFly would most likely be used on servers which are normally not booted that often, however as I run it on my laptop I wouldn't mind a faster boot :-) Obviously it could(should?) be made optional. Geert
Re: shutdown on BSD and Linux
BTW - the poweroff on my laptop, with Dragonfly and FreeBSD (last I checked), is also accompanied by a rather alarming and short-lived whine, as if a spinning disk or fan was suddenly stopped. I don't get this sound with linux or windows. I had an older system that would do this with the fans; I never saw a negative effect. I assumed it was some setting that was tripped as systems were shutdown, which made the fans react as if the temperature was too high - perhaps the equivalent of a burst of static. I never saw a negative effect either. It was just an alarming sound. I have a computer on which the fan-controls does not start working until somewhere post BIOS, before that they run for full. Might be something like that but in reverse, the fan-control is disabled and the fans run for full by default. How does the computer sound when it starts? My fans are pretty noisy and come on full blast on power-on, die away initially, and come on again after a bit. Then they stay on. It's an old Pentium-IV based HP laptop and runs pretty warm (and I live in a tropical city). I'm not totally sure this poweroff-time sound is the fan though. Rahul
Re: shutdown on BSD and Linux
Justin C. Sherrill wrote: PS: By the way, recently someone suggested in a FreeBSD mailing list that start scripts could be run in parallel if they don't depend on each other (which rcorder(8) can easily find out). It would probably speed up booting. However, I don't know if anyone is actually working on implementing that. As I recall, Apple's launchd is a replacement for rc (and init and inetd), and runs in parallel. (My Mac does start up very fast indeed, though launchd is not the only reason) http://developer.apple.com/documentation/Darwin/Reference/ManPages/man8/launchd Ubuntu too is starting on a replacement for init, called upstart https://wiki.ubuntu.com/ReplacementInit The developer says he would have started with launchd if it had had a free licence to begin with, and even now they don't seem happy with the licence. I tried upstart on my laptop and got the fastest console login I have ever seen: within a couple of seconds of the kernel loading, I could log in to my home directory, even as it continued to probe other hardware, connect to the network, etc. The graphical login (kdm in my case) takes much longer, I think about as long as with old-fashioned init. Rahul
Re: Shutdown
saw wrote @ Tue, 09 May 2006 12:34:38 +0200: Thomas Schlesinger wrote: Hi, when I shutdown my notebook (ASUS V6800), I get a message to power it of on console, but it doesn't happen automagically as in Linux. I believe to remember, that I've read somewhere something about an sysctl switch which enables this function, but I can't find it again. I'm not sure, it was DFly related, it could also be FBSD related. How do you shutdown? 'shutdown -p now' should do the trick. Or just use the power button. -- Andy
Re: Shutdown
:Or just use the power button. : :-- :Andy Yup. When ACPI works, anyhow. Its a godsend for turnkey systems, I can just tell the computer illiterates to hit the power button and wait for the thing to power itself off. -Matt Matthew Dillon [EMAIL PROTECTED]
Re: Shutdown
On 2006-05-09 12:29, Thomas Schlesinger wrote: Hi, when I shutdown my notebook (ASUS V6800), I get a message to power it of on console, but it doesn't happen automagically as in Linux. I believe to remember, that I've read somewhere something about an sysctl switch which enables this function, but I can't find it again. I'm not sure, it was DFly related, it could also be FBSD related. Does anyone know how to make an ACPI-enabled notebook to power off on shutdown automatically? I've attache a sysctl hw output of my notebook to this email. I've got a IBM T41 and it works just fine. I've compared my sysctl- output with yours and could not find any difference in the ACPI- settings. Is the result the same when using the power-button? Are you running a GENERIC-kernel, if not try with one. And just to be sure, you are using the -p option to shutdown(8) right? Sorry I couldn't be of more help. Erik Wikström -- I have always wished for my computer to be as easy to use as my telephone; my wish has come true because I can no longer figure out how to use my telephone -- Bjarne Stroustrup
Re: Shutdown
Am Dienstag, 9. Mai 2006 12:34 schrieb Sascha Wildner: Thomas Schlesinger wrote: Hi, when I shutdown my notebook (ASUS V6800), I get a message to power it of on console, but it doesn't happen automagically as in Linux. I believe to remember, that I've read somewhere something about an sysctl switch which enables this function, but I can't find it again. I'm not sure, it was DFly related, it could also be FBSD related. How do you shutdown? 'shutdown -p now' should do the trick. Sascha Yes. indeed, that works. I didn't know about the -p option. RTFM ;-) Now I have to teach KDE to use this switch... Thanks, Thomas
Re: Shutdown
Sascha Wildner wrote: Thomas Schlesinger wrote: Hi, when I shutdown my notebook (ASUS V6800), I get a message to power it of on console, but it doesn't happen automagically as in Linux. I believe to remember, that I've read somewhere something about an sysctl switch which enables this function, but I can't find it again. I'm not sure, it was DFly related, it could also be FBSD related. How do you shutdown? 'shutdown -p now' should do the trick. Sascha Typically, I used 'halt -p' instead of 'shutdown -p now'. Now I'm wondering if there's a major difference. Either way, it shutdown my computer. Joey
Re: Shutdown
On 2006-05-10 00:12, Joseph Garcia wrote: Sascha Wildner wrote: Thomas Schlesinger wrote: Hi, when I shutdown my notebook (ASUS V6800), I get a message to power it of on console, but it doesn't happen automagically as in Linux. I believe to remember, that I've read somewhere something about an sysctl switch which enables this function, but I can't find it again. I'm not sure, it was DFly related, it could also be FBSD related. How do you shutdown? 'shutdown -p now' should do the trick. Sascha Typically, I used 'halt -p' instead of 'shutdown -p now'. Now I'm wondering if there's a major difference. Either way, it shutdown my computer. Not really sure but I believe that shutdown calls halt or reboot, so the results should be roughly the same. I think shutdown sends a message to all users logged in before calling halt, can be used to put the system down at a specific time etc. while halt just shuts down now. Erik Wikström -- I have always wished for my computer to be as easy to use as my telephone; my wish has come true because I can no longer figure out how to use my telephone -- Bjarne Stroustrup
