TABLE OF CONTENTS

trackdisk.device/CMD_CLEAR
trackdisk.device/CMD_READ
trackdisk.device/CMD_UPDATE
trackdisk.device/CMD_WRITE
trackdisk.device/TD_ADDCHANGEINT
trackdisk.device/TD_CHANGENUM
trackdisk.device/TD_CHANGESTATE
trackdisk.device/TD_EJECT
trackdisk.device/TD_FORMAT
trackdisk.device/TD_GETDRIVETYPE
trackdisk.device/TD_GETGEOMETRY
trackdisk.device/TD_GETNUMTRACKS
trackdisk.device/TD_MOTOR
trackdisk.device/TD_PROTSTATUS
trackdisk.device/TD_RAWREAD
trackdisk.device/TD_RAWWRITE
trackdisk.device/TD_REMCHANGEINT
trackdisk.device/TD_SEEK
trackdisk.device/CMD_CLEAR                         trackdisk.device/CMD_CLEAR

   NAME
	CMD_CLEAR/ETD_CLEAR -- mark the track buffer as containing invalid
			       data.

   FUNCTION
	These commands mark the track buffer as invalid, forcing a
	reread of the disk on the next operation. ETD_UPDATE or CMD_UPDATE
	would be used to force data out to the disk before turning the motor
	off. ETD_CLEAR or CMD_CLEAR are usually used after having locked out
	the trackdisk.device via the use of the disk resource, when you
	wish to prevent the track from being updated, or when you wish to
	force the track to be re-read. ETD_CLEAR or CMD_CLEAR will not do an
	update, nor will an update command do a clear.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	CMD_CLEAR or ETD_CLEAR
	io_Flags	0 or IOF_QUICK
	iotd_Count	(ETD_CLEAR only) maximum allowable change counter
			value.

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>

   SEE ALSO
	CMD_WRITE, CMD_UPDATE

trackdisk.device/CMD_READ                           trackdisk.device/CMD_READ

   NAME
	CMD_READ/ETD_READ -- read sectors of data from a disk.

   FUNCTION
	These commands transfer data from the track buffer to a supplied
	buffer. If the desired sector is already in the track buffer, no disk
	activity is initiated. If the desired sector is not in the buffer, the
	track containing that sector is automatically read in. If the data in
	the current track buffer has been modified, it is written out to the
	disk before a new track is read. ETD_READ will read the sector label
	area if the iotd_SecLabel is non-NULL.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	CMD_READ or ETD_READ
	io_Flags	0 or IOF_QUICK
	io_Data		pointer to the buffer where the data should be put
	io_Length	number of bytes to read, must be a multiple of
			TD_SECTOR.
	io_Offset	byte offset from the start of the disk describing
			where to read data from, must be a multiple of
			TD_SECTOR.
	iotd_Count	(ETD_READ only) maximum allowable change counter
			value.
	iotd_SecLabel	(ETD_READ only) NULL or sector label buffer pointer.
			If provided, the buffer must be a multiple of
			TD_LABELSIZE.

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>
   NOTES
	Under versions of Kickstart earlier than V36, the io_Data had to
	point to a buffer in chip memory. This restriction is no longer
	present as of Kickstart V36 and beyond.

   SEE ALSO
	CMD_WRITE

trackdisk.device/CMD_UPDATE                       trackdisk.device/CMD_UPDATE

   NAME
	CMD_UPDATE/ETD_UPDATE -- write out the track buffer if it is dirty.

   FUNCTION
	The trackdisk device does not write data sectors unless it is
	necessary (you request that a different track be used) or until the
	user requests that an update be performed. This improves system speed
	by caching disk operations. These commands ensure that any
	buffered data is flushed out to the disk. If the track buffer has not
	been changed since the track was read in, these commands do nothing.
	ETD_UPDATE command checks for diskchange.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	CMD_UPDATE or ETD_UPDATE
	io_Flags	0 or IOF_QUICK
	iotd_Count	(ETD_UPDATE only) maximum allowable change counter
			value.

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>

   SEE ALSO
	CMD_WRITE

trackdisk.device/CMD_WRITE                         trackdisk.device/CMD_WRITE

   NAME
	CMD_WRITE/ETD_WRITE -- write sectors of data to a disk.

   FUNCTION
	These commands transfer data from a supplied buffer to the track
	buffer. If the track that contains this sector is already in the track
	buffer, no disk activity is initiated. If the desired sector is not in
	the buffer, the track containing that sector is automatically read in.
	If the data in the current track buffer has been modified, it is
	written out to the disk before the new track is read in for
	modification. ETD_WRITE will write the sector label area if
	iotd_SecLabel is non-NULL.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	CMD_WRITE or ETD_WRITE
	io_Flags	0 or IOF_QUICK
	io_Data		pointer to the buffer where the data should be put
	io_Length	number of bytes to write, must be a multiple of
			TD_SECTOR.
	io_Offset	byte offset from the start of the disk describing
			where to write data to, must be a multiple of
			TD_SECTOR.
	iotd_Count	(ETD_WRITE only) maximum allowable change counter
			value.
	iotd_SecLabel	(ETD_WRITE only) NULL or sector label buffer pointer.
			If provided, the buffer must be a multiple of
			TD_LABELSIZE.

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>

   NOTES
	Under versions of Kickstart earlier than V36, the io_Data had to
	point to a buffer in chip memory. This restriction is no longer
	present as of Kickstart V36 and beyond.

   SEE ALSO
	CMD_READ, TD_FORMAT

trackdisk.device/TD_ADDCHANGEINT             trackdisk.device/TD_ADDCHANGEINT

   NAME
	TD_ADDCHANGEINT -- add a disk change software interrupt handler.

   FUNCTION
	This command lets you add a software interrupt handler to the
	disk device that gets invoked whenever a disk insertion or removal
	occurs.

	You must pass in a properly initialized Exec Interrupt structure
	and be prepared to deal with disk insertions/removals
	immediately. From within the interrupt handler, you may only call the
	status commands that can use IOF_QUICK.

	To set up the handler, an Interrupt structure must be initialized.
	This structure is supplied as the io_Data to the TD_ADDCHANGEINT
	command. The handler then gets linked into the handler chain and
	gets invoked whenever a disk change happens. You must eventually
	remove the handler before you exit.

	This command only returns when the handler is removed. That is,
	the device holds onto the IO request until the TD_REMCHANGEINT command
	is executed with that same IO request. Hence, you must use SendIO()
	with this command.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	TD_ADDCHANGEINT
	io_Flags	0
	io_Length	sizeof(struct Interrupt)
	io_Data		pointer to Interrupt structure

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>

   SEE ALSO
	TD_REMCHANGEINT, <devices/trackdisk.h>, <exec/interrupts.h>,
	exec.library/Cause()

trackdisk.device/TD_CHANGENUM                   trackdisk.device/TD_CHANGENUM

   NAME
	TD_CHANGENUM -- return the current value of the disk-change counter.

   FUNCTION
	This command returns the current value of the disk-change counter (as
	used by the enhanced commands). The disk change counter is incremented
	each time a disk is inserted or removed from the trackdisk unit.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	TD_CHANGENUM
	io_Flags	0 or IOF_QUICK

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>
	io_Actual - if io_Error is 0, this contains the current value of the
		    disk-change counter.

trackdisk.device/TD_CHANGESTATE               trackdisk.device/TD_CHANGESTATE

   NAME
	TD_CHANGESTATE -- check if a disk is currently in a drive.

   FUNCTION
	This command checks to see if there is currently a disk in a drive.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	TD_CHANGESTATE
	io_Flags	0 or IOF_QUICK

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>
	io_Actual - if io_Error is 0, this tells you whether a disk is in
		    the drive. 0 means there is a disk, while anything else
		    indicates there is no disk.

trackdisk.device/TD_EJECT                           trackdisk.device/TD_EJECT

   NAME
       TD_EJECT -- eject the disk in the drive, if possible.

   FUNCTION
	This command causes the drive to attempt to eject the disk in
	it, if any.  Note that the current trackdisk.device does not
	implement this command, but it might in the future, and other
	trackdisk-compatible drivers may implement this command.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	TD_EJECT
	io_Flags	0 or IOF_QUICK

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>

trackdisk.device/TD_FORMAT                         trackdisk.device/TD_FORMAT

   NAME
	TD_FORMAT/ETD_FORMAT -- format a track on a disk.

   FUNCTION
	These commands are used to write data to a track that either
	has not yet been formatted or has had a hard error on a standard write
	command. TD_FORMAT completely ignores all data currently on a track and
	does not check for disk change before performing the command. The
	io_Data field must point to at least one track worth of data. The
	io_Offset field must be track aligned, and the io_Length field must be
	in units of track length (that is, NUMSEC*TD_SECTOR).

	The device will format the requested tracks, filling each sector with
	the contents of the buffer pointed to by io_Data. You
	should do a read pass to verify the data.

	If you have a hard write error during a normal write, you may find it
	possible to use the TD_FORMAT command to reformat the track as part of
	your error recovery process. ETD_FORMAT will write the sector label
	area if iotd_SecLabel is non-NULL.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	TD_FORMAT or ETD_FORMAT
	io_Flags	0 or IOF_QUICK
	io_Data		points to a buffer containing the data to write to the
			track, must be at least as large as io_Length.
	io_Length	number of bytes to format, must be a multiple of
			(TD_SECTORS * NUMSEC).
	io_Offset	byte offset from the start of the disk for the track to
			format, must be a multiple of (TD_SECTORS * NUMSEC).
	iotd_Count	(ETD_FORMAT only) maximum allowable change counter
			value.
	iotd_SecLabel	(ETD_FORMAT only) NULL or sector label buffer pointer.
			If provided, the buffer must be a multiple of
			(TD_LABELSIZE * NUMSEC).

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>

   NOTES
	Under versions of Kickstart earlier than V36, the io_Data had to
	point to a buffer in chip memory. This restriction is no longer
	present as of Kickstart V36 and beyond.

   SEE ALSO
	CMD_WRITE, TD_RAWWRITE

trackdisk.device/TD_GETDRIVETYPE             trackdisk.device/TD_GETDRIVETYPE

   NAME
	TD_GETDRIVETYPE -- return the type of disk drive for the unit that was
			   opened.

   FUNCTION
	This command returns the type of the disk drive to the user.
	This number will be a small integer and will come from the set of
	DRIVEXXX constants defined in <devices/trackdisk.h>.

	The only way you can actually use this command is if the trackdisk
	device understands the drive type of the hardware that is plugged in.
	This is because the OpenDevice() call will fail if the trackdisk device
	does not understand the drive type. To find raw drive identifiers see
	the disk.resource's DR_GETUNITID entry point.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	TD_GETDRIVETYPE
	io_Flags	0 or IOF_QUICK

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>
	io_Actual - if io_Error is 0 this contains the drive type connected to
		    this unit.

   SEE ALSO
	TD_GETNUMTRACKS, <devices/trackdisk.h>

trackdisk.device/TD_GETGEOMETRY               trackdisk.device/TD_GETGEOMETRY

   NAME
       TD_GETGEOMETRY -- return the geometry of the drive.

   FUNCTION
	This command returns a full set of information about the
	layout of the drive. The information is returned in the
	DriveGeometry structure pointed to by io_Data.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	TD_GETGEOMETRY
	io_Flags	0 or IOF_QUICK
	io_Data		Pointer to a DriveGeometry structure
	io_Length	sizeof(struct DriveGeometry)

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>

   NOTE
	This information may change when a disk in inserted when
	certain hardware is present.

   SEE ALSO
	TD_GETDRIVETYPE, TD_GETNUMTRACKS

trackdisk.device/TD_GETNUMTRACKS             trackdisk.device/TD_GETNUMTRACKS

   NAME
	TD_GETNUMTRACKS -- return the number of tracks for the type of disk
			   drive for the unit that was opened.

   FUNCTION
	This command returns the number of tracks that are available
	on the disk unit.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	TD_GETNUMTRACKS
	io_Flags	0 or IOF_QUICK

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>
	io_Actual - if io_Error is 0 this contains the drive type connected to
		    this unit.

   SEE ALSO
	TD_GETDRIVETYPE

trackdisk.device/TD_MOTOR                           trackdisk.device/TD_MOTOR

   NAME
	TD_MOTOR/ETD_MOTOR -- control the on/off state of a drive motor.

   FUNCTION
	This command gives control over the disk motor. The motor may be
	turned on or off. When it is on, the drive light automatically turns
	on as well.

	If the motor is just being turned on, the device will delay the
	proper amount of time to allow the drive to come up to speed. Normally,
	turning the drive on is not necessary, the device does this
	automatically if it receives a request when the motor is off. However,
	turning the motor off is the programmer's responsibility.

	In addition, the standard instructions to the user are that it is safe
	to remove a disk from a drive if and only if the motor is off (that is,
	if the disk light is off).

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	TD_MOTOR or ETD_MOTOR
	io_Flags	0 or IOF_QUICK
	io_Length	the requested state of the motor, 0 to turn the motor
			off, and 1 to turn the motor on.
	iotd_Count	(ETD_MOTOR only) maximum allowable change counter
			value.

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>
	io_Actual - if io_Error is 0 this contains the previous state of the
		    drive motor.

trackdisk.device/TD_PROTSTATUS                 trackdisk.device/TD_PROTSTATUS

   NAME
	TD_PROTSTATUS -- return whether the current disk is write-protected.

   FUNCTION
	This command is used to determine whether the current disk is
	write-protected.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	TD_PROTSTATUS
	io_Flags	0 or IOF_QUICK

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>
	io_Actual - if io_Error is 0, this tells you whether the disk in the
		    drive is write-protected. 0 means the disk is NOT write-
		    protected, while any other value indicates it is.

trackdisk.device/TD_RAWREAD                       trackdisk.device/TD_RAWREAD

   NAME
	TD_RAWREAD/ETD_RAWREAD -- read raw data from the disk.

   FUNCTION
	These commands read a track of raw data from disk and deposits it in
	the provided buffer. The data is taken straight from the disk with
	no processing done on it. It will appear exactly as the bits come out
	off the disk, hopefully in some legal MFM format.

	This interface is intended for sophisticated programmers only.
	Amiga, Inc. reserves the right to make enhancements to the disk
	format in the future. We will provide compatibility via the
	CMD_READ and ETD_READ commands, anyone using TD_RAWREAD is
	bypassing this upwards compatibility, and may thus stop working.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command      TD_RAWREAD or ETD_RAWREAD.
	io_Flags	if the IOTDB_INDEXSYNC bit is set then the driver
			will make a best effort attempt to start reading
			from the index mark.  Note that there will be at
			least some delay, and perhaps a great deal of delay
			(for example if interrupts have been disabled).
	io_Length	Length of buffer in bytes, with a maximum of 32768
			bytes.
	io_Data		Pointer to CHIP memory buffer where raw track data is
			to be deposited.
	io_Offset	The number of the track to read in.
	iotd_Count	(ETD_RAWREAD only) maximum allowable change counter
			value.

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>

   NOTES
	The track buffer provided MUST be in CHIP memory

	There is a delay between the index pulse and the start of bits
	coming in from the drive (e.g. dma started). This delay
	is in the range of 135-200 microseconds. This delay breaks
	down as follows: 55 microsecs is software interrupt overhead
	(this is the time from interrupt to the write of the DSKLEN
	register). 66 microsecs is one horizontal line delay (remember
	that disk IO is synchronized with agnus' display fetches).
	The last variable (0-65 microsecs) is an additional scan line
	since DSKLEN is poked anywhere in the horizontal line. This leaves
	15 microsecs unaccounted for...  Sigh.

	In short, You will almost never get bits within the first 135
	microseconds of the index pulse, and may not get it until 200
	microseconds. At 4 microsecs/bit, this works out to be between
	4 and 7 bytes of user data of delay.

   BUGS
	This command does not work reliably under versions of Kickstart
	earlier than V36, especially on systems with 1 floppy drive.

   SEE ALSO
	TD_RAWWRITE

trackdisk.device/TD_RAWWRITE                     trackdisk.device/TD_RAWWRITE

   NAME
	TD_RAWWRITE/ETD_RAWWRITE -- write raw data to the disk.

   FUNCTION
	This command writes a track of raw data from the provided buffer to
	the specified track on disk. The data is copied straight to the disk
	with no processing done on it. It will appear exactly on the disk as
	it is in the memory buffer, hopefully in a legal MFM format.

	This interface is intended for sophisticated programmers only.
	Amiga, Inc. reserves the right to make enhancements to the disk
	format in the future. We will provide compatibility via the
	CMD_WRITE and ETD_WRITE commands, anyone using TD_RAWWRITE is
	bypassing this upwards compatibility, and may thus stop working.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command      TD_RAWWRITE or ETD_RAWWRITE.
	io_Flags	if the IOTDB_INDEXSYNC bit is set then the driver
			will make a best effort attempt to start writing
			from the index mark.  Note that there will be at
			least some delay, and perhaps a great deal of delay
			(for example if interrupts have been disabled).
	io_Length	Length of buffer in bytes, with a maximum of 32768
			bytes.
	io_Data		Pointer to CHIP memory buffer where raw track data is
			to be taken.
	io_Offset	The number of the track to write to.
	iotd_Count	(ETD_RAWWRITE only) maximum allowable change counter
			value.

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>

   NOTES
	The track buffer provided MUST be in CHIP memory

	There is a delay between the index pulse and the start of bits
	going out to the driver (e.g. write gate enabled). This delay
	is in the range of 135-200 microseconds. This delay breaks
	down as follows: 55 microsecs is software interrupt overhead
	(this is the time from interrupt to the write of the DSKLEN
	register). 66 microsecs is one horizontal line delay (remember
	that disk IO is synchronized with agnus' display fetches).
	The last variable (0-65 microsecs) is an additional scan line
	since DSKLEN is poked anywhere in the horizontal line. This leaves
	15 microsecs unaccounted for...  Sigh.

	In short, You will almost never get bits within the first 135
	microseconds of the index pulse, and may not get it until 200
	microseconds. At 4 microsecs/bit, this works out to be between
	4 and 7 bytes of user data of delay.

   BUGS
	This command does not work reliably under versions of Kickstart
	earlier than V36, especially on systems with 1 floppy drive.

   SEE ALSO
	TD_RAWREAD

trackdisk.device/TD_REMCHANGEINT             trackdisk.device/TD_REMCHANGEINT

   NAME
	TD_REMCHANGEINT -- remove a disk change software interrupt handler.

   FUNCTION
	This command removes a disk change software interrupt added
	by a previous use of TD_ADDCHANGEINT.

   IO REQUEST INPUT
	The same IO request used for TD_ADDCHANGEINT.

	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	TD_REMCHANGEINT
	io_Flags	0
	io_Length	sizeof(struct Interrupt)
	io_Data		pointer to Interrupt structure

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>

   BUGS
	This command did not function properly under versions of Kickstart
	earlier than V36. A valid workaround under these older versions of
	Kickstart is:

		Forbid();
		Remove(ioRequest);
		Permit();

	Do not use this workaround in versions of Kickstart >= V36, use
	TD_REMCHANGEINT instead (for future compatibility with V38+).

   SEE ALSO
	TD_ADDCHANGEINT, <devices/trackdisk.h>

trackdisk.device/TD_SEEK                             trackdisk.device/TD_SEEK

   NAME
	TD_SEEK/ETD_SEEK -- control positioning of the drive heads.

   FUNCTION
	These commands are currently provided for internal diagnostics,
	disk repair, and head cleaning only.

	TD_SEEK and ETD_SEEK move the drive heads to the track specified. The
	io_Offset field should be set to the (byte) offset to which the seek is
	to occur. TD_SEEK and ETD_SEEK do not verify their position until the
	next read. That is, they only move the heads; they do not actually read
	any data.

   IO REQUEST INPUT
	io_Device	preset by the call to OpenDevice()
	io_Unit		preset by the call to OpenDevice()
	io_Command	TD_SEEK or ETD_SEEK
	io_Flags	0 or IOF_QUICK
	io_Offset	byte offset from the start of the disk describing
			where to move the head to.
	iotd_Count	(ETD_SEEK only) maximum allowable change counter
			value.

   IO REQUEST RESULT
	io_Error - 0 for success, or an error code as defined in
	           <devices/trackdisk.h>