Hello! I wasn't sure what Daniel wanted. The more complicated explanation. Or the overly simplified one. Or one that left our friend even more confused.
The one presented is largely based on an explanation given to me by one of the folks at Dallas Semiconductor shortly after the whole business got started, and in an interesting accent that I realized was one of the neighborhood where they were based. ----- Gregg C Levine gregg.drw...@gmail.com "This signature fought the Time Wars, time and again." On Sun, Feb 15, 2015 at 3:01 PM, Paul Alfille <paul.alfi...@gmail.com> wrote: > Hi Daniel, > > Gregg answered the more general philosophy of 1-wire architecture. Let me > address your questions narrowly. > > All the 1-wire chips (well, almost all except the DS1821) have a unique ID > that can be queried by the 1-wire "discovery" protocol. When you ask for a > "directory listing" in OWFS it has all the 1-wire devices enumerate > themselves. > > You can ask for a directory listing periodically (preferably uncached) to > check the available devices. Although plugging in new device will send a > "presence pulse" it's unreliable (easily lost in other bus traffic) and thus > not used by OWFS. Periodic polling is the best way. > > Paul > > On Sun, Feb 15, 2015 at 2:14 PM, Gregg Levine <gregg.drw...@gmail.com> > wrote: >> >> Hello! >> A good question. One I've asked myself countless times, before Paul >> wrote his excellent tool set and realized there was a better way to >> manage certain storage methods. >> >> Let's say you own an iButton of the type who contains a DS2401 >> electronic serial number. Inserting it into the reader will prompt the >> computer to examine it, and add it to the list of displayed devices. >> The serial number on it, will be the displayed along with everything >> else known about it. >> >> For example one of the many ideas that the company who originated them >> had was to contain a standard real time clock that would contain all >> of the features their real time clocks have and indeed that was the >> case. >> >> A third party company makes a specialty reader who when pressed >> against one of them is told the time of day and encloses it in its >> files. Further it can be used in place of the recording clocks that >> watchmen used for an eternity of walking around buildings. And in fact >> my food store uses them for their day-to-day activities as applied to >> that one. >> >> At one point the company was working with a company to make up >> doorlocks that would only open when a matching button was shown to it. >> >> It gets even stranger. >> >> At the height of the Java business, they even made a button who would >> contain an application, and indeed the fun one was to have the thing >> send the host computer to show the owner's website in all its >> (typically badly) written glory. >> >> Incidentally those numbers that each device wears have a story behind >> them. It seems that during the process of development someone there >> discovered that they resembled the codes worn by Ethernet cards so >> they made arrangements with the authorities behind that to register >> them accordingly. They are as seemingly random as the UUID entries >> that can be created using the appropriate software, but that's where >> the two part company. >> ----- >> Gregg C Levine gregg.drw...@gmail.com >> "This signature fought the Time Wars, time and again." >> >> >> On Sun, Feb 15, 2015 at 1:04 PM, Daniel MacKay <dan...@bonmot.ca> wrote: >> > OK, I'm going to come across as really stunned here, but if I don't ask, >> > I won't learn. >> > >> > I am accustomed to having devices -- mostly temperature sensors -- on my >> > 1W bus, getting a catalog of them by hand, and then entering the serial >> > numbers into a configuration file in my sofware, which then queries them >> > once every five minutes. >> > >> > So with an iButton, some guy comes up to the iButton base, sticks the >> > iButton in and... what happens? >> > >> > How does the software (mine is in Perl) know that: >> > a) something has happened on the bus that it should do something and, >> > b) what the number of the iButton that just got stuck in, is? >> > >> >> >> ------------------------------------------------------------------------------ >> Dive into the World of Parallel Programming. The Go Parallel Website, >> sponsored by Intel and developed in partnership with Slashdot Media, is >> your >> hub for all things parallel software development, from weekly thought >> leadership blogs to news, videos, case studies, tutorials and more. Take a >> look and join the conversation now. http://goparallel.sourceforge.net/ >> _______________________________________________ >> Owfs-developers mailing list >> Owfs-developers@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/owfs-developers > > > > ------------------------------------------------------------------------------ > Dive into the World of Parallel Programming. The Go Parallel Website, > sponsored by Intel and developed in partnership with Slashdot Media, is your > hub for all things parallel software development, from weekly thought > leadership blogs to news, videos, case studies, tutorials and more. Take a > look and join the conversation now. http://goparallel.sourceforge.net/ > _______________________________________________ > Owfs-developers mailing list > Owfs-developers@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/owfs-developers > ------------------------------------------------------------------------------ Dive into the World of Parallel Programming. The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
