FileIO & performance question

[GSR]

Hi,

I have 2 Labview 101 questions. Could you please help?

• Functions»All Functions»File I/O»Advanced File Functions>>New File vi. I read a book which said this vi has an input of datalog type. Then I read the VI examples, I see an example which write the data into file with this VI. The datalog input is a bundle with string and DBLs. I also read the VI which read the output file generated by the previous VI. This VI also have the bundle (I can understand this part), but it also need me to open a datalog file (I don't understand this part). What is that datalog file? Doesn't the bundle contain all the information to read the data file??
  
• Tools for identifying memory and performance issues
  i. Profile memory and performance
  ii. Show buffer allocations
  iii. VI metrics
  Can I find these topics from Labview for everyone?
  

[jdunham]

QUOTE (zmarcoz @ Jan 10 2009, 07:05 AM)

• Functions»All Functions»File I/O»Advanced File Functions>>New File vi. I read a book which said this vi has an input of datalog type. Then I read the VI examples, I see an example which write the data into file with this VI. The datalog input is a bundle with string and DBLs. I also read the VI which read the output file generated by the previous VI. This VI also have the bundle (I can understand this part), but it also need me to open a datalog file (I don't understand this part). What is that datalog file? Doesn't the bundle contain all the information to read the data file??
  

The datalog type can be any type you want (your strings and DBLs was probably just an example), but files don't have to be datalog type. If you don't wire the datalog type, you get a normal (binary or text) file which can be understood by other programs. Datalog files are LabVIEW-specific, but have pretty much been abandoned by NI which now recommends using TDMS or LVM files. The problem is that datalog files are not self-describing, so if you don't have the original program which created the file, you can't read the file.