Functions
Abstract: Start an asynchronous read or write operation.
public:
virtual IOReturn doAsyncReadWrite(IOMemoryDescriptor *buffer,
UInt32 block,UInt32 nblks,
gdCompletionFunction action,
IOService *target,void *param) = 0;
Parameters
Name | Description |
buffer | An IOMemoryDescriptor describing the data-transfer buffer. The data direction
is contained in the IOMemoryDescriptor. Responsiblity for releasing the descriptor
rests with the caller. |
block | The starting block number of the data transfer. |
nblks | The integral number of blocks to be transferred. |
action | The C function called upon completion of the data transfer. |
target | The C++ class "this" pointer, passed as an argument to "action." |
param | This value is passed as an argument to "action." It is not validated or modified. |
Abstract: Eject the media.
public:
virtual IOReturn doEjectMedia(void) = 0;
Abstract: Format the media to the specified byte capacity.
public:
virtual IOReturn doFormatMedia(UInt64 byteCapacity) = 0;
The specified byte capacity must be one supported by the device.
Supported capacities can be obtained by calling doGetFormatCapacities.
Parameters
Name | Description |
byteCapacity | The byte capacity to which the device is to be formatted, if possible. |
Abstract: Return the allowable formatting byte capacities.
public:
virtual UInt32 doGetFormatCapacities(UInt64 * capacities,
UInt32 capacitiesMaxCount) const = 0;
This function returns the supported byte capacities for the device.
Parameters
Name | Description |
capacities | Pointer for returning the list of capacities. |
capacitiesMaxCount | The number of capacity values returned in "capacities." |
Abstract: Lock or unlock the (removable) media in the drive.
public:
virtual IOReturn doLockUnlockMedia(bool doLock) = 0;
This method should only be called if the media is known to be removable.
Parameters
Name | Description |
doLock | True to lock the media, False to unlock. |
Abstract: Perform a synchronous read or write operation.
public:
virtual IOReturn doSyncReadWrite(IOMemoryDescriptor *buffer,
UInt32 block,UInt32 nblks) = 0;
Parameters
Name | Description |
buffer | An IOMemoryDescriptor describing the data-transfer buffer. The data direction
is contained in the IOMemoryDescriptor. Responsiblity for releasing the descriptor
rests with the caller. |
block | The starting block number of the data transfer. |
nblks | The integral number of blocks to be transferred. |
Abstract: Force data blocks in the drive's buffer to be flushed to the media.
public:
virtual IOReturn doSynchronizeCache(void) = 0;
This method should only be called if the media is writable.
Abstract: Issue the client's cdb as a pass-through.
public:
virtual IOReturn executeCdb(struct cdbParams *params) = 0;
This method is provided to allow developers to issue arbitrary commands
to the device (via the Transport Driver). Expected uses would include vendor-specific
commands to effect password-protection, or for other vendor features.
This method may not be supported by all Transport Drivers. For example, ATA devices
do not have a CDB concept; those Transport Drivers will return kIOReturnUnsupported.
Parameters
Name | Description |
params | See IOHDTypes.h for the layout of this data structure. |
Abstract: Return additional informational string for the device.
public:
virtual char * getAdditionalDeviceInfoString(void) = 0;
Result: A pointer to a static character string.
Abstract: Return Product Name string for the device.
public:
virtual char * getProductString(void) = 0;
Result: A pointer to a static character string.
Abstract: Return Product Revision string for the device.
public:
virtual char * getRevisionString(void) = 0;
Result: A pointer to a static character string.
Abstract: Return Vendor Name string for the device.
public:
virtual char * getVendorString(void) = 0;
Result: A pointer to a static character string.
public:
virtual bool init(OSDictionary * properties);
This function is overridden so that IOHDDriveNub can set a
property, used by IOHDDrive for matching. Since the concrete subclass of
IOHDDriveNub can be of any class type, the property is used for matching.
This function is usually not overridden by developers.
Abstract: Report the block size for the device, in bytes.
public:
virtual IOReturn reportBlockSize(UInt64 *blockSize) = 0;
Parameters
Name | Description |
blockSize | Pointer to returned block size value. |
Abstract: Report if the media is ejectable under software control.
public:
virtual IOReturn reportEjectability(bool *isEjectable) = 0;
This method should only be called if the media is known to be removable.
Parameters
Name | Description |
isEjectable | Pointer to returned result. True indicates the media is ejectable, False indicates
the media cannot be ejected under software control. |
Abstract: Report if the media is lockable under software control.
public:
virtual IOReturn reportLockability(bool *isLockable) = 0;
This method should only be called if the media is known to be removable.
Parameters
Name | Description |
isLockable | Pointer to returned result. True indicates the media can be locked in place; False
indicates the media cannot be locked by software. |
Abstract: Report the maximum allowed byte transfer for read operations.
public:
virtual IOReturn reportMaxReadTransfer(UInt64 blockSize,UInt64 *max) = 0;
Some devices impose a maximum data transfer size. Because this limit
may be determined by the size of a block-count field in a command, the limit may
depend on the block size of the transfer.
Parameters
Name | Description |
blockSize | The block size desired for the transfer. |
max | Pointer to returned result. |
Abstract: Report the highest valid block for the device.
public:
virtual IOReturn reportMaxValidBlock(UInt64 *maxBlock) = 0;
Parameters
Name | Description |
maxBlock | Pointer to returned result |
Abstract: Report the maximum allowed byte transfer for write operations.
public:
virtual IOReturn reportMaxWriteTransfer(UInt64 blockSize,UInt64 *max) = 0;
Some devices impose a maximum data transfer size. Because this limit
may be determined by the size of a block-count field in a command, the limit may
depend on the block size of the transfer.
Parameters
Name | Description |
blockSize | The block size desired for the transfer. |
max | Pointer to returned result. |
Abstract: Report the device's media state.
public:
virtual IOReturn reportMediaState(bool *mediaPresent,bool *changedState) = 0;
This method reports whether we have media in the drive or not, and
whether the state has changed from the previously reported state.
A result of kIOReturnSuccess is always returned if the test for media is successful,
regardless of media presence. The mediaPresent result should be used to determine
whether media is present or not. A return other than kIOReturnSuccess indicates that
the Transport Driver was unable to interrogate the device. In this error case, the
outputs mediaState and changedState will *not* be stored.
Parameters
Name | Description |
mediaPresent | Pointer to returned media state. True indicates media is present
in the device; False indicates no media is present. |
changedState | Pointer to returned result. True indicates a change of state since
prior calls, False indicates that the state has not changed. |
Abstract: Report if it's necessary to poll for media insertion, and if polling is expensive.
public:
virtual IOReturn reportPollRequirements(bool *pollRequired,
bool *pollIsExpensive) = 0;
This method reports whether the device must be polled to detect media
insertion, and whether a poll is expensive to perform.
The term "expensive" typically implies a device that must be spun-up to detect media,
as on a PC floppy. Most devices can detect media inexpensively.
Parameters
Name | Description |
pollRequired | Pointer to returned result. True indicates that polling is required; False indicates
that polling is not required to detect media. |
pollIsExpensive | Pointer to returned result. True indicates that the polling operation is expensive;
False indicates that the polling operation is cheap. |
Abstract: Report whether the media is removable or not.
public:
virtual IOReturn reportRemovability(bool *isRemovable) = 0;
This method reports whether the media is removable, but it does not
provide detailed information regarding software eject or lock/unlock capability.
Parameters
Name | Description |
isRemovable | Pointer to returned result. True indicates that the media is removable; False
indicates the media is not removable. |
Abstract: Report whether the media is write-protected or not.
public:
virtual IOReturn reportWriteProtection(bool *isWriteProtected) = 0;
Parameters
Name | Description |
isWriteProtected | Pointer to returned result. True indicates that the media is write-protected (it
cannot be written); False indicates that the media is not write-protected (it
is permissible to write). |
© 2000 Apple Computer, Inc. (Last Updated 2/23/2000)