Dear All,

Can I download several executable programs to NXT at one time so that I can start any one I need without re-compile and download it again? The current action seems to be newly-downloaded program always overwriting old one.

Your programs have different names, right? The NXT can store as many programs as you want until it runs out of memory. There is a file name limit of 20-characters, I think, so if multiple programs are the same for the first 20 (or however many it is) characters, then the last one downloaded will be the only one on it.

NeXT-Generation is correct. If you compile and download a program to the NXT and there is already a program on the NXT with the same name, the old one will be overwritten by the new one. To avoid this, all you have to do is save your modified program with a slightly different name (test1.c and test2.c, for example) before compiling and downloading.

This is done by navigating to the File -> Save As menu option and changing the file name before saving it. Then, once the program is compiled and downloaded to the NXT you can check to see which programs are on the brick one of two ways; either by navigating to the 'My Files -> Software Files' submenu on the brick itself or by opening the 'Robot -> NXT Brick -> File Management Utility' in ROBOTC.

The advantage of using the File Management Utility is that it will show you all the files on the NXT (including user programs) and allow you to manually upload, download, rename, and delete files on the NXT. If you wish to download program files, however, they will need to be compiled and downloaded through ROBOTC (you can't download program files directly to the NXT using the File Management Utility because it does not compile the programs beforehand).