Re: Unix Philosophers Please!
Bernd Walter [EMAIL PROTECTED] writes: In short: The data is tranfered into the kernel and dropped there. The data is never transferred into the kernel. There is no copyin() or uiomove() there. DES -- Dag-Erling Smorgrav - [EMAIL PROTECTED] To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
On Wed, Oct 31, 2001 at 03:02:59PM -0600, Nicpon, John wrote:
Please specifically define where data goes that is sent to /dev/null
That's what manpages are for - see null(4).
If you want it more specific src/sys/dev/null.c says:
[...]
static int
null_write(dev_t dev, struct uio *uio, int flag)
{
uio-uio_resid = 0;
return 0;
}
[...]
The memory which holds the data is declared as unused now and may be
overwritten at any time.
Even if the data still exists you will loose the reference to the
holding memory on return of null_write().
In short: The data is tranfered into the kernel and dropped there.
--
B.Walter COSMO-Project http://www.cosmo-project.de
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Re: Unix Philosophers Please!
On Thu, Nov 01, 2001 at 08:29:39PM +, lg wrote: In short: The data is tranfered into the kernel and dropped there. my source /usr/src/sys/i386/i386/mem.c [FreeBSD-4.3-RELEASE] says that data doesnt transfered into kernel. I was looking into -current. Null and *random have been seprarated in -current. kernel just do: (when you write to device with major 2, minor 2) c = iov-iov_len; iov-iov_base += c; iov-iov_len -= c; uio-uio_offset += c; uio-uio_resid -= c; [ where iov is uio-uio_iov ] so data doesnt go anywhere. Sorry - you are right. No data is copied into the kernel as it would be the job of null_write() to do if needed. -- B.Walter COSMO-Project http://www.cosmo-project.de [EMAIL PROTECTED] Usergroup [EMAIL PROTECTED] To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
Nicpon, John [EMAIL PROTECTED] writes: Please specifically define where data goes that is sent to /dev/null It goes into a special data sink in the CPU where it is converted to heat which is vented through the heatsink / fan assembly. This is why CPU cooling is increasingly important; as people get used to faster processors, they become careless with their data and more and more of it ends up in /dev/null, overheating their CPUs. If you delete /dev/null (which effectively disables the CPU data sink) your CPU may run cooler but your system will quickly become constipated with all that excess data and start to behave erratically. If you have a fast network connection you can cool down your CPU by reading data out of /dev/random and sending it off somewhere; however you run the risk of overheating your network connection and / or angering your ISP, as most of the data will end up getting converted to heat by their equipment, but they generally have good cooling, so if you don't overdo it you should be OK. I hope this answers your question. DES -- Dag-Erling Smorgrav - [EMAIL PROTECTED] To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
Answer 2. All the data goes into another dimension, and comes out of /dev/random. That would be so funny... I cat /dev/random, and I get your files, as you delete them. 8-). Of course you do, it is just that the bytes are in random order. But I see that you are thinking of /dev/null as a bitbucket for files. Hmm... that means we can get rid of the unlink() given an atomic rename() syscall. mv file1 file2 dir1 et cetera et cetera et cetera /dev/null Neat! To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Unix Philosophers Please!
Please specifically definewheredata goes that is sent to /dev/null
Re: Unix Philosophers Please!
On Wed, Oct 31, 2001 at 03:02:59PM -0600, Nicpon, John wrote: Please specifically define where data goes that is sent to /dev/null How 'specific' are you trying to get? /dev/null is a pseudo-device to which writes never fail. What question are you _really_ trying to ask? -- Brian 'you Bastard' Reichert[EMAIL PROTECTED] 37 Crystal Ave. #303Daytime number: (603) 434-6842 Derry NH 03038-1713 USA Intel architecture: the left-hand path To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
Nicpon, John wrote: Please specifically define where data goes that is sent to /dev/null The bit bucket. You won't have to empty the one in your machine until the year 2038, which we assume someone will come up with a way of recyling the used bits by then (or just compressing them into bus benches). -- Terry To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
On Wed, 31 Oct 2001, Brian Reichert wrote: On Wed, Oct 31, 2001 at 03:02:59PM -0600, Nicpon, John wrote: Please specifically define where data goes that is sent to /dev/null How 'specific' are you trying to get? /dev/null is a pseudo-device to which writes never fail. What question are you _really_ trying to ask? -- Brian 'you Bastard' Reichert [EMAIL PROTECTED] 37 Crystal Ave. #303 Daytime number: (603) 434-6842 Derry NH 03038-1713 USA Intel architecture: the left-hand path To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message --- Geoff Mohler To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
Nicpon, John wrote:
Please specifically define where data goes that is sent to /dev/null
Without actually looking at the code, the generic definition of /dev/null goes
something to the effect of:
open /dev/null
while(1)
{
select on /dev/null
read byte from /dev/null
}
So basically, it just reads what is there, but does absolutely nothing with it.
jim
--
ET has one helluva sense of humor!
He's always anal-probing right-wing schizos!
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RE: Unix Philosophers Please!
ethersWhere does data go when it dies?/ethers -Original Message- From: Brian Reichert [mailto:[EMAIL PROTECTED]] Sent: Wednesday, October 31, 2001 3:08 PM To: Nicpon, John Cc: [EMAIL PROTECTED] Subject: Re: Unix Philosophers Please! On Wed, Oct 31, 2001 at 03:02:59PM -0600, Nicpon, John wrote: Please specifically define where data goes that is sent to /dev/null How 'specific' are you trying to get? /dev/null is a pseudo-device to which writes never fail. What question are you _really_ trying to ask? -- Brian 'you Bastard' Reichert[EMAIL PROTECTED] 37 Crystal Ave. #303Daytime number: (603) 434-6842 Derry NH 03038-1713 USA Intel architecture: the left-hand path To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
It's similar to the space/time wormhole that appears in your clothes dryer, and randomly sucks out only one sock out of every pair into a parallel universe. Somewhere, there is a universe made up of nothing but odd socks, where they each lead a very happy odd-sockish singular life. I assume that input to /dev/null goes to a parallel universe consisting entirely of unwanted, wayward data. Nicpon, John wrote: ethersWhere does data go when it dies?/ethers -Original Message- From: Brian Reichert [mailto:[EMAIL PROTECTED]] Sent: Wednesday, October 31, 2001 3:08 PM To: Nicpon, John Cc: [EMAIL PROTECTED] Subject: Re: Unix Philosophers Please! On Wed, Oct 31, 2001 at 03:02:59PM -0600, Nicpon, John wrote: Please specifically define where data goes that is sent to /dev/null How 'specific' are you trying to get? /dev/null is a pseudo-device to which writes never fail. What question are you _really_ trying to ask? jim -- ET has one helluva sense of humor! He's always anal-probing right-wing schizos! - POWER TO THE PEOPLE! - Religious fundamentalism is the biggest threat to international security that exists today. United Nations Secretary General B.B.Ghali, 1995 _ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
Nicpon, John wrote: Please specifically define where data goes that is sent to /dev/null to the place where no data ever came back. -- Mathieu Arnold To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
Nicpon, John wrote: Please specifically define where data goes that is sent to /dev/null to the place where no data ever came back. ..on those blank tapes on which you should be backing up the data you do care about. ..to help fight the secret, hidden war against entropy. To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
In message [EMAIL PROTECTED], Joh [EMAIL PROTECTED] writes: What question are you _really_ trying to ask? What is the sound of one hand clapping? To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
On Wed, Oct 31, 2001 at 03:08:38PM -0700, Drew Eckhardt wrote: In message [EMAIL PROTECTED], Joh [EMAIL PROTECTED] writes: What question are you _really_ trying to ask? What is the sound of one hand clapping? If a bit falls into the bit bucket and signal is not raised does it make a sound? Next week: Why do hot dogs come in packages of 12 and hot dog buns in packages of 8? Extra credit: Why are all the good ones taken? Is this a demo of how supply side economics is not working? Josef -- Josef Grosch | Another day closer to a | FreeBSD 4.4 [EMAIL PROTECTED] | Micro$oft free world | www.bafug.org To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
Nicpon, John wrote: Please specifically define where data goes that is sent to /dev/null Answer 1. Data is not like energy. There is no conservation of data law. So the data simply disappears. Answer 2. All the data goes into another dimension, and comes out of /dev/random. -- Stephen Montgomery-Smith [EMAIL PROTECTED] http://www.math.missouri.edu/~stephen To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
Stephen Montgomery-Smith wrote: Answer 2. All the data goes into another dimension, and comes out of /dev/random. That would be so funny... I cat /dev/random, and I get your files, as you delete them. 8-). -- Terry To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
On Wed, Oct 31, 2001 at 03:08:38PM -0700, Drew Eckhardt wrote: In message [EMAIL PROTECTED], Joh [EMAIL PROTECTED] writes: What question are you _really_ trying to ask? What is the sound of one hand clapping? Can this go to -chat please?? -- | / o / /_ _ email: [EMAIL PROTECTED] |/|/ / / /( (_) Bulte Arnhem, The Netherlands To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
On Wed, 31 Oct 2001, Stephen Montgomery-Smith wrote: Nicpon, John wrote: Please specifically define where data goes that is sent to /dev/null Answer 1. Data is not like energy. There is no conservation of data law. So the data simply disappears. Doesn't thermodynamics second law actually imply that data has to disappear and that with the heat death of the universe data will be at a minimum? For meaningful data to exist there needs to be order, while the 2nd law requires that systems evolve to less ordered states. The only uncertainty about this that I've got is that random systems can actually be very dense with data. Think about a compressed and encrypted file, which should be indistinguishable from /dev/random output. I guess the difference between those two is that there is only a single state which validly represents the comprssed and encrypted file. On the other hand there may be many states which represent the valid output of /dev/random (of course you only obtain one of these states). Since there are more states for /dev/random there is more entropy (and actually the compressed file having only one valid state would have minimal entropy). Did I get that right? My thermodynamics and info theory are a little rusty... Contribute to the Heat Death of the Universe! pipe everything to /dev/null! To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
Lamont Granquist wrote: On Wed, 31 Oct 2001, Stephen Montgomery-Smith wrote: Nicpon, John wrote: Please specifically define where data goes that is sent to /dev/null Answer 1. Data is not like energy. There is no conservation of data law. So the data simply disappears. Doesn't thermodynamics second law actually imply that data has to disappear and that with the heat death of the universe data will be at a minimum? For meaningful data to exist there needs to be order, while the 2nd law requires that systems evolve to less ordered states. The only uncertainty about this that I've got is that random systems can actually be very dense with data. Think about a compressed and encrypted file, which should be indistinguishable from /dev/random output. I guess the difference between those two is that there is only a single state which validly represents the comprssed and encrypted file. On the other hand there may be many states which represent the valid output of /dev/random (of course you only obtain one of these states). Since there are more states for /dev/random there is more entropy (and actually the compressed file having only one valid state would have minimal entropy). Did I get that right? My thermodynamics and info theory are a little rusty... Contribute to the Heat Death of the Universe! pipe everything to /dev/null! Nah, you have it all wrong... The data goes into a wormhole, much similar to the one that splits up your pairs of socks in the dryer, and the data wormhole simply sucks it into another universe. No need to worry about the collapse of our universe because of /dev/null BUT...Piping all that data to /dev/null MAY destroy the universe that keeps sending flying saucers to the houses of Art Bell fans in places like Lockjaw, Kentucky or Moose Turd, Montana... jim -- ET has one helluva sense of humor! He's always anal-probing right-wing schizos! - POWER TO THE PEOPLE! - Religious fundamentalism is the biggest threat to international security that exists today. United Nations Secretary General B.B.Ghali, 1995 _ Do You Yahoo!? Get your free @yahoo.com address at http://mail.yahoo.com To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
On Wed, Oct 31, 2001 at 05:20:33PM -0800, Lamont Granquist wrote: On Wed, 31 Oct 2001, Stephen Montgomery-Smith wrote: Nicpon, John wrote: Please specifically define where data goes that is sent to /dev/null Answer 1. Data is not like energy. There is no conservation of data law. So the data simply disappears. Doesn't thermodynamics second law actually imply that data has to disappear and that with the heat death of the universe data will be at a minimum? For meaningful data to exist there needs to be order, while the 2nd law requires that systems evolve to less ordered states. Maybe, but the second law of thermodynamics is incorrect so who knows? Joe PGP signature
Re: Unix Philosophers Please!
On Wed, 31 Oct 2001, Nicpon, John wrote: Please specifically define where data goes that is sent to /dev/null To boldy go where no Data has returned from before? -- Chad Ziccardi, Professional Slacker [EMAIL PROTECTED] Some cause happiness wherever they go; others whenever they go. To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
Re: Unix Philosophers Please!
Please specifically define where data goes that is sent to /dev/null The same place where /dev/random gets its data from. Unless your computer is owned by gummint, in which case FBI gets it as you have to keep a copy of all output. To Unsubscribe: send mail to [EMAIL PROTECTED] with unsubscribe freebsd-hackers in the body of the message
