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Inside Macintosh: Devices /

Chapter 4 - SCSI Manager 4.3 / SCSI Manager 4.3 Reference

SCSI Manager 4.3 Functions / Client Functions

SCSILoadDriver

The Start Manager uses the SCSILoadDriver function to provide an opportunity for a SIM to load a driver other than one found on the media.

OSErr SCSIAction(SCSILoadDriverPB *scsiPB);

scsiPB

A pointer to a SCSI load driver parameter block, which is described on page 4-34.

-->	scsiPBLength	UInt16	The size of the parameter block.
-->	scsiFunctionCode	UInt8	The SCSILoadDriver function selector code (0x82).
<--	scsiResult	OSErr	The returned result code.
-->	scsiDevice	DeviceIdent	The device identification record.
-->	scsiCompletion	CallbackProc	A pointer to a completion routine. If this field is set to nil, the function is executed synchronously.
-->	scsiDriverStorage	UInt8 *	Optional pointer to the device driver's private storage.
<--	scsiLoadedRefNum	UInt16	The driver reference number returned by the SIM.
-->	scsiDiskLoadFailed	Boolean	Set to true if a driver could not be loaded from the media.

DESCRIPTION

The SCSILoadDriver function is called by the Start Manager to load device drivers for SCSI devices. You can use this function to load a driver for a device that was not available at system startup.

The Start Manager can call this function both before and after attempting to load a driver from the media. On the first attempt, the scsiDiskLoadFailed field is set to false, indicating to the SIM that it can choose to load a driver from the media or install another (typically newer) driver of its own choosing.

If the first attempt to load a driver fails, the Start Manager calls the SCSILoadDriver function a second time, with the scsiDiskLoadFailed field set to true to indicate that a driver could not be loaded from the media. The SIM then loads its own driver, if possible, or returns an error result.

SPECIAL CONSIDERATIONS

The SCSILoadDriver function may move memory; you should not call it at interrupt time.

RESULT CODES

noErr	0	No error
scsiFunctionNotAvailable	-7871	The requested function is not supported by this SIM