Bingo! Roberto is correct.
We'll, take the question in stages:
1. Electrical limitations
Dallas has a Application note discussing the electrical limitations of a
1-wire network. This includes the total length (due to propagation delays) and
total capacitance (due to wire and devices).
http://www.maxim-ic.com/appnotes.cfm/appnote_number/148
2. Software limitations
A. OWFS was designed for this situation. There is no inherent limit on the
number of devices. There is no required memory allocation per device.
B. Cache will fill with more devices. It is flushed automatically, and
degrades gracefully when full. Currently full is triggered my memory allocation
failure, but we could be more elegant if required. (Memory is part of the
general pool, and memory allocation failure will upset other OWFS functions).
C. Some adapters (like the HA7) require the entire device list to exist in
memory. This will potentially limit the maximum nuber of devices. Again, if this
is a true concern, there are solutions.
D. Even with cache, 2MB of ram should allow 10^5 devices. If you can afford
a larger network, spend a little on RAM as well.
3. Partitioning
If the electrical limitations are met, adding more adapters will partition
the problem. There is an implicit union of the separate 1-wire busses.-----Original Message----- From: [EMAIL PROTECTED] on behalf of Roberto Spadim Sent: Mon 10/2/2006 7:39 PM To: [email protected] Subject: Re: [Owfs-developers] How many single switches can be connected? (FWD) about 2^48 could work, i think that the main problem is fuse work with many files, cache can be very large, memory usage very high, processor stay low cause ow is an halfduplex bus Gregg C Levine escreveu: > Hello! > The message below my signature was created and posted from one of my other > subscribed e-mail accounts. As of a few minutes ago it has not arrived. Nor > is it in the archives. So I am posting it here, and below my signature. If > there are any complaints about duplicating messages, please contact me > directly. > -- > Gregg C Levine [EMAIL PROTECTED] > "The Force will be with you. Always." Obi-Wan Kenobi > ---- > Hello! > How many switches can OWFS support directly? These are the DS2406 > style device by the way. And no I haven't built the actual hardware, > that comes later. > > It's just that with the release of the DS2408 and many successful > applications of the thing, I just can't recall my question ever coming > up in discussions. And Paul this includes the original One-Wire > discussion that ran on the list supplied by Dallas Semi before they > made the ill-fated decision to switch to a forum rather then continue > with the list ideas. > > For example, I have an idea of reasonable capabilities that would > involve using these switches to generate a pattern to be written to > yes a character displaying LCD display (Company name and part number > to be chosen later) but I'd rather not go down this path if it won't > work. > > In fact I even don't recall the actual number of supported devices > being discussed anyplace surfacing. I believe the number is limited to > the way the network is accessed, but that's an opinion only. > > It's amazing what happens to a person's memory when that person gets > to be the same age as Master Yoda. (Joke!) > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys -- and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Owfs-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/owfs-developers
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