Required and Optional Tape Miniclass Routines

A tape miniclass driver must have the following routines:

  • DriverEntry provides driver-specific entry points and constants that the tape class driver uses to initialize the miniclass driver.

    The tape miniclass driver's DriverEntry routine allocates a TAPE_INIT_DATA_EX structure, sets driver-specific constants and entry points in the structure, and calls TapeClassInitialize in the tape class driver.

  • Routines that implement device-specific processing for device-control requests, such as TapeMiniGetPosition and TapeMiniGetMediaTypes.

    The tape class driver calls such routines from its device-control dispatch routine. For more information, see Processing Tape Device Control Requests.

A tape miniclass driver can have the following optional routines:

  • TapeMiniExtensionInit initializes the optional minitape extension.

    See Storing Tape Miniclass Context in Optional Extensions For information about minitape extensions.

  • TapeMiniTapeError supplements the error handling of the tape class driver.

    For most devices, the tape class driver can return an appropriate status value when an error occurs without input from the tape miniclass driver. For some devices, however, the tape class driver requires device-specific information from the tape miniclass driver to return the appropriate status. For example, the miniclass driver for 4mm DAT tape drives can determine that, in certain situations, a TAPE_STATUS_BUS_RESET status is actually due to no media in the drive. The 4mm DAT miniclass driver's TapeMiniTapeError routine identifies these situations and changes the status that is returned to TAPE_ERROR_NO_MEDIA.

The tape miniclass driver's DriverEntry routine must use that name exactly in order to be loaded automatically by the operating system. TapeMiniXxx routines can be named as the driver writer chooses, as long as the entry points of the routines are set in the TAPE_INIT_DATA_EX structure. To aid in debugging, a miniclass driver should prefix the TapeMiniXxx routines with some characters to identify itself and should ensure the rest of the characters in the name reflect what the routine does.

See also the description of tape miniclass routines in Tape Miniclass Driver Routines.