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_AddDrive, _DrvrInstall, and _DrvrRemove are used in the sample SCSI driver in the
SCSI Development Package. This Technical Note documents the parameters for these calls.
Updated: [March 1987]
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_AddDrive
_AddDrive adds a drive to the drive queue, and is discussed in more detail
in Technical Note #36, Drive Queue Elements:
FUNCTION AddDrive(DQE:DrvQE1;driveNum,refNum:INTEGER):OSErr;
A0 (input) -> pointer to DQE
D0 high word(input) -> drive number
D0 low word(input) -> driver RefNum
D0 (output) <- error code
noErr (always returned)
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_DrvrInstall
_DrvrInstall is used to install a driver. A DCE for the driver
is created and its handle entered into the specified Unit Table position (-1 through -64).
If the unit number is -4 through -9, the corresponding ROM-based driver will be replaced:
FUNCTION DrvrInstall(drvrHandle:Handle; refNum: INTEGER): OSErr;
A0 (input) -> pointer to driver
D0 (input) -> driver RefNum (-1 through -64)
D0 (output) <- error code
noErr
badUnitErr
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_DrvrRemove
_DrvrRemove is used to remove a driver. A RAM-based driver is purged from
the system heap (using _ReleaseResource). Memory for the DCE is disposed:
FUNCTION DrvrRemove(refNum: INTEGER):OSErr;
D0 (input) -> Driver RefNum
D0 (output) <- error code
noErr
qErr
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Interfaces
Through a sequence of cataclysmic events, the glue code for _DrvrInstall and
_DrvrRemove was never actually added to the MPW interfaces (i.e., "We forgot."), so
we will include simple glue here at no extra expense to you.
It would be advisable to first lock the handle to your driver with _HLock before
making either of these calls since memory may be moved.
;---------------------------------------------------------------
; FUNCTION DRVRInstall(drvrHandle:Handle; refNum:INTEGER):OSErr;
;---------------------------------------------------------------
DRVRInstall PROC EXPORT
MOVEA.L (SP)+, A1 ; pop return address
MOVE.W (SP)+, D0 ; driver reference number
MOVEA.L (SP)+, A0 ; handle to driver
MOVEA.L (A0), A0 ; pointer to driver
_DrvrInstall ; $A03D
MOVE.W D0, (SP) ; get error
JMP (A1) ; & split
ENDPPROC
;---------------------------------------------------------------
; FUNCTION DRVRRemove(refNum:INTEGER):OSErr;
;---------------------------------------------------------------
DRVRRemove PROC EXPORT
MOVEA.L (SP)+, A1 ; pop return address
MOVE.W (SP)+, D0 ; driver reference number
_DrvrRemove ; $A03E
MOVE.W D0, (SP) ; get error
JMP (A1) ; & split
ENDPPROC
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Change History
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01-March-1987
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Originally written.
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01-March-1988
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Updated the _DrvrInstall text to
reflect the use of register A0, which should contain a pointer to the
driver when called. Also added simple glue code for _DrvrInstall and
_DrvrRemove since none is available in the MPW interfaces.
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Downloadables
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Acrobat version of this Note (52K)
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Download
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