remote reliable data acquisition

On 2005-02-05, Badhri wrote: : I am working on a solution for wireless remote data acquisition The : remote device runs embedded linux mounted on a Compact Flash and is : connected to a set of peers by standard wireless ethernet : transponder(802.11b,using adhoc mode).I need to stream the data on to a : basestation,by multihop routing.(which could be another peer)Since the : data is sensor information,I need to transfer this reliably too. : : 1. Do I need to build an database server(like SQL),build a database and : stream data through a web server??Will this be a huge footprint??Can I : stream data by using this??will this work in an adhoc scenario??Also I : can use it to transfer data both ways right? : : 2.Does anyone have an idea of a modbus interface???I heard it is used : for all handheld/embedded data acquisition. : : 3.If I dont use a database...How do you buffer data in the case of a : network outage/limited connectivity....??? : : 4.Suppose I timestamp data and write it to a file and then ftp them,is : there a better way to do this? :

Since you posted this to the Kermit newsgroup, here's the Kermit perspective. Kermit (like FTP) is a file transfer protocol, so I'm not sure how that would fit in with your requirement for streaming. Still, you can't just stream data indefinitely, right? At some point you have to store it in a file, or something like a file. In that case, of course you can use Kermit or FTP, and this will have a much smaller footprint, and fewer points of failure than some combination of SQL databases, web servers, and so forth. To the extent that your application can be forced into the file model, either Kermit or FTP would be fine. Of course FTP comes with Linux, and in most cases so does Kermit; if not, it's readily available:

This gives you a relatively off-the-shelf, simple solution. The advantage of Kermit over FTP is that it includes its own built-in scripting language for automation:

Kermit itself is an FTP client too, and this implementation includes the same scripting language:

- Frank