TapeOpen

TapeOpen is a Windows API function used to obtain a handle to a magnetic tape device for subsequent tape operations. It is part of the Windows Tape API, a set of interfaces used by backup and archival software to control tape drives and read or write data to magnetic media. The function typically accepts a device path such as \\.\TAPE0 and an access mode, returning a handle on success or an error code on failure. The handle is then used with other tape-related calls, including DeviceIoControl with IOCTL_TAPE_* codes and an associated set of TapeIO routines to perform operations like read, write, repositioning, filemark handling, rewinding, and media retension.

In practice, TapeOpen is used within the Windows Driver Kit environment or by applications that rely on the Windows Tape subsystem. It requires appropriate privileges and a correctly installed tape device driver. Errors commonly indicate issues such as missing or offline devices, being in use by another process, or insufficient permissions.

The Tape API originated with Windows NT-era storage support and remains documented for compatibility with legacy backup software and enterprise data management. While many modern backup strategies prefer networked storage, cloud archives, or virtual tape libraries, TapeOpen and related IOCTLs still appear in certain on-premises environments for compatibility with older hardware and software stacks. Cross-platform tape access is provided by other libraries and drivers, but TapeOpen itself is a Windows-specific entry point.

See also: Windows Tape API, DeviceIoControl, IOCTL_TAPE_ code references.