Hi !

[Noam]

I have Labview 4.0.1 on Windows-NT:

To compare 2 files i'm ussing 2 "Read characters file.vi" when the "characters string" output of this 2 functions is connect to one "Comparison Equal ?" symbol, which it's output is connect to an LED indicator on the front panel.

( The second part of my question is in the "Additional Text" text box ) When i Run this application i choose the 2 files for compare ( using the file browswer ) and as a result i get the Led On/Off ( Equal or Not Equal ).

My question is if what i did good also for comparing large files for example if i want to compare the files "Test1.exe" and "Test2.exe" which are 7 Mbytes ( each one ). i ask this becouse i remember that there is a limit
for the number of chars in the strin
g i can send to the input of the "Comparison Equal ?" symbol, is it true ? is there a limit ? ( Becouse a 7 Mbytes file is a very very long string ..... and i want to be sure that the comparing is done only on the beginning of this files ..... )

I hope you understood, please answer as soon, thanks.

And i have a remark for you, it's very good and very nice that you are trying to improve your services but this limit of "400 charakters for a Question" is very hard, there are questons that it's very very hard to write in leass then 400 characters ... and if you are doing it why don't you put a counter ( as i saw in other sites ) that shows in real time how many characters i wrote ? should i guess it or count it when i'm writing my question ?????????????

Noam.

noam_opsigal@hotmail.com

[Gorka Larrea]

Don't know about the limits of read characters vi, but if you want to compare the beginig of the file, just limit the number of characters read, so that everytime you read a file, this does not exceed the number set. This will limit the reading to a size you want.
Hope this helps

[Noam]

Hi and thank you for your answer,

But you did not understand me ( the True is that is was my mistake ...) , i DO WANT to be sure that the comparing is done NOT only on the beginning of this files, i want to compare ALL the file from beginning till the end and i want to know if the vi i did will also compare for me a very large files ( which makes a very long string to compare ... )

About the limit of 400 characters i was talking about that when i tried to post my question i got a message "Your message can't be more that 400 characters long", so i was talking about this.

Thanks again,

Noam.

[markwysong]

I don't see a reason that you couldn't use some of the File I/O VIs to accomplish this. If you open the file, you can then use the Read File VI and specify the number of characters to read. An output of this VI is a read marker, which indicates the position of the read marker in the file after the number of characters have been read. By putting the read from file VI inside a loop, you can read and compare "chunks" of the files instead of all at once; just check to see if any "chunk" doesn't match. Then you don't use much memory, and your file sizes can be virtually unlimited (limited only by the drive size). I do this type of file reading all the time, and my files are about 100 MByte.

I can show you an example if you wish.

Mark

[Noam]

Yes, i would like to see your example please !

Thanks

[andreasz]

Hello,

sorry that I ask you for this example as well, like a spy. But that example would also help me a lot.

My problem:

I would like to acquire 64byte of data and I would like to compare this data with the following captured 64byte stream. If equal the application hase to stop if not the next 64bytes must be acquired and must be compared with the first 64byte reference and so on!

Sorry that I interfere in your business!

Andreas