Universal Storage Interface Do you know it? How do I get started?

[Ben]

While reviewing code not writtien by myself (I can not post the code, believe me I am more sorry than you think) I ran across the LV Storage VIs.

One of the error codes I ran across "-2564"

Gives a KB article about the Universal Storage Interface being required for an exe.

A quick glance at these VIs and the example give me the same feeling I had when I first looked at LVOOP code, "Cool but how the H32$ does it work and how can exploit this critter?"

So if you have got a handle on the Storage VIs I would greatly appreciate any light you can shed on using the Storage VIs and exploiting same.

Ben

[tst]

If memory serves, the storage VIs are XNodes, although I have to admit I have no idea what the VIs actually do and I don't have LV in front of me. I believe there should be some documentation on LAVA or the wiki on how to dig into existing Xnodes. Darin's example from the last couple of coding challenges should also help.

[Jarrod_S. · Accepted solution]

What exactly are you wanting to know? Are you asking for help regarding the error you saw, or just for general info about the storage VIs themselves?

The storage VIs are really cool technology, primarily for reading files from many different formats. You can write many file formats as well, but the storage VIs are not optimized for streaming data quickly to disk. Use the TDMS functions directly for that.

The coolest thing about the storage VIs is that they provide a TDMS-like interface (channel groups, channels, named properties and data) for many different file formats using a plug-in system. So you can download plugins that allow the storage VIs to read (and sometimes write) different formats like TDM, TDMS, CSV, TXT, DAT, MDF, MAT, XML and so on. This is great for your users, because you can provide them a general tool and then let them use the file format of their choice that they already have. Starting in 2010 the storage VIs can even auto-detect which plug-in to use. Before that you had to manually choose the right plug-in yourself based on the file format and what plug-ins were installed. Very cool.

The Storage VIs are wrappers around the USI layer, which originated I believe in the Diadem technology. I said before they are optimized for reading data quickly, not for writing it. This has to do with the TDM storage format, which is the base format for the storage VIs. TDM always stores all of a channel's data contiguously in the file. This makes it really quick to do search, analysis and other types of processing. However, it is not ideal for streaming data to disk, because generally you're trying to write small bits of many channels at a time. Trying to do this while keeping all of each channel's data together is not optimal.

[Ben]

Well than kyou very much Jarrod!

You handled both parts of my question (prvided the tutoial stuff is good).

This looks like some powerful stuff once I get my head wrapped around it and bending it to my will.

Pssstt: We don't have to tell anyone else about this do we?

Ben