Running NVDA Automatically from a USB Drive

Introduction

One of NVDA's great features is the ability to run it from a portable USB drive without needing administrative privileges or previously installed software. If you do this frequently, it might be convenient to have NVDA start automatically when you connect the USB drive to a computer. This article discusses how this can be done and issues that may be encountered.

Prerequisites

• AutoPlay must be enabled in Windows for any of these instructions to work. This is the default. However, it may be disabled by users or administrators on some systems.

U3 Drives

If you have a U3 drive, you can configure it to start NVDA automatically when it is connected. See RunningNVDAFromAnU3Drive for instructions on doing this.

Normal USB Drives in Windows XP

It is not possible to start NVDA automatically without a prompt when a normal USB drive is connected. For information about why, see Further Information. However, in Windows XP Service Pack 2 and later, it is possible to have NVDA start by pressing the enter key after connecting a USB drive. To do this:

• Extract a portable version of NVDA to a directory called nvda in the root directory of your USB drive.
• Download autorun.inf and save it as autorun.inf in the root directory of your USB drive.

Normal USB Drives in Windows Vista

Windows Vista can be configured to start programs automatically when a normal USB drive is connected. Once this is done, the same autorun.inf file can be used as described above.

Further Information

AutoRun/AutoPlay

Since Windows 95, Windows has provided the ability to have a program start automatically when a CD is inserted. This functionality is called AutoRun. For CDs, this occurs without prompting the user. Windows determines what program to run by examining a file called autorun.inf in the root directory of the drive. See  this article for more information.

Unfortunately, this does not work for normal portable USB drives in Windows XP. (See the answer to the question "What must I do to trigger Autorun on my USB storage device?" in  this article for technical details.) This is probably due to security concerns. USB drives are removable and writable, which means that it is very simple for someone to configure a drive to run a malicious program which might be automatically run when the drive is connected by an unsuspecting user.

Windows XP and later provide a facility called AutoPlay, which presents a dialog to the user when a drive is connected or media is inserted. This dialog allows the user to choose the action to take based on the content of the drive. In Windows XP Service Pack 2 and later, it is possible to specify a program to appear as the first selection in this dialog. (This is done by specifying the action option in the [AutoRun] section of the autorun.inf file.) Although this is not quite automatic, it means that you can start a program by simply connecting the drive and pressing enter.

Windows Vista can be configured to start programs automatically when a USB drive is connected.

U3 Drives

U3 drives are a special type of USB drive with modified hardware. As well as presenting a standard USB drive, they also present an emulated CDROM drive. This emulated CDROM drive contains an autorun.inf file and a launcher application. Because AutoRun works without prompting on CDROM drives, the launcher is started automatically and can launch other applications such as NVDA. See  the U3 article in Wikipedia for more information.