Managing Files and Memory on the NXT

It is sometimes necessary to manage files and memory on the NXT. You can do this by accessing the Memory tab of the NXT window that is launched from the upper left button of the controller.

The memory tab of the NXT window provides a graphical overview of memory usage on your NXT. From here you can also send programs, sounds, graphics and other files to your NXT from a PC, and copy and delete files that are already on your NXT.

1. A graphical overview of used and available memory.
2. The different file categories (programs, sounds, graphics, other...) that take up the NXTs memory. Clicking on a category name will display these types of files in the list.
3. A list of files in the currently selected category.
4. Delete. This button deletes any selected files from the NXT.
5. Download. This button will download files from your PC to the NXT.
6. Upload. This button will copy any selected files from the NXT to your PC.
7. Delete all User Files. This button deletes all user files and cleans up the NXTs memory.
8. Show System Files. Checking this box will reveal all factory-installed files on the NXT.

The NXTs memory

Each NXT has an available memory of about 130.7 kilobytes. Some of this memory is used to store example programs, graphics and sound files that are pre-loaded on the NXT device when you first get it. This leaves about 56 kilobytes for the files you create and download.

Running out of memory

If you run out of memory you can delete some or all of the files on your NXT. To do this, examine the memory overview graphic to the left (1) and identify which types of files take up most memory. Click that category name (2) and its files will be displayed in the list. Select the files you don’t need in the list and click the Delete button.

Deleting all of your files

You can erase all of your created files and clean up the NXTs memory by clicking the Delete all User Files button. This will delete all of the files you have ever sent to the NXT and re-organize the memory to leave the maximum amount free for new files. Doing this will not delete any of the system files that were pre-loaded in the NXT at the factory.

You can also delete files using the icons on the NXT itself. For details, see the NXT Technology section in the printed User Guide.

Freeing up as much memory as possible

If deleting your user files does not free up enough memory, you can also delete the demo and example files that came pre-loaded in the NXT. These files are referred to as system files and take up around 62 kilobytes. The system files include the start-up and other sounds as well as the demo and Try Me programs.

You can always restore the NXT device’s memory back to factory default condition (with all of the system files) by restoring the firmware. See "Restoring an NXTs memory..." below.

To delete system files, check the Show System Files box (8). Then select a file category (2) and choose the system files you want to remove (3). Click Delete for each file you want to erase from memory.

Here is a list of the system files and the features they enable:

Category	File name	Description
Other	NVConfig.sys	Settings like sleep time and volume are stored in this file. If you delete this file, a new one will be created automatically.
	Try-*.rtm	Any system file starting with "Try-" is a Try Me program for a specific sensor or output. Deleting each of these will remove the individual Try Me programs from the Try Me NXT menu.
	RPGreader.sys	This program lets you run NXT programs (programs that are created on the NXT itself using the NXT Program icon). Deleting this file will remove the ability to run programs made on the NXT. Programs created and downloaded from a PC will still work.
	*.tmp	Any file ending with ".tmp" is a temporary file. Temporary files can always be deleted.
	*.bak	Any file ending with ".bak" is a temporary file. Temporary files can always be deleted.
Graphics	faceopen	Picture of LEGO minifig head (with mouth open) used in the Try Me programs.
	faceclosed	Picture of LEGO minifig head (with mouth closed) used in the Try Me programs.
Sounds	Woops	Sound file used in the Try Me programs. Deleting this file will remove the sound from the programs it is used in. The programs will still work without the sound.
	! Startup	Sound file played when the NXT starts up. Deleting this file will remove the sound at start up.
	! Click	Sound file played when a button is pressed on the NXT. Deleting this file will remove the sound when a button is pressed on the NXT.
	! Attention	Sound file played when the NXT issues a warning. Deleting this file will remove the sound when a warning is issued.
Programs	Demo	Demo program for the Quick Start model. Deleting this will remove the Demo program from the NXT.

Restoring an NXTs memory back to factory default condition

You can restore an NXTs memory back to factory default condition by re-installing the NXT firmware. For details on this operation, see the Help topic, "Updating the NXTs Firmware." Be aware that re-installing the NXT firmware will delete all files in the NXTs memory -- make sure to make a back up of any personal files you want to keep before proceeding.

Copying and backing up files stored on the NXT

To make a back up copy of your personal files or to share files stored on the NXT with friends, you should copy the files off the NXT to your PC.

To do this, first select the file category (2) for the files you would like to back up or share. Select the desired files in the list (3) and click Upload (7). Finally, select the folder where the files will be saved on your PC and click OK.

Sending a file back to the NXT

To send a file back to the NXT, click the Download (5) button. Select the file you want to copy from your PC and click OK.