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 floppy(7)							   floppy(7)




 NAME
      floppy - direct flexible or ``floppy'' disk access

 DESCRIPTION
      Flexible disk devices are removable-media disk devices that are
      typically used to share data with other systems.	Media types are
      identified by physical size (such as 3.5-inch and 5.25-inch), number
      of data surfaces (or sides), and data density.  By convention,
      flexible disk devices are named using the same conventions as those
      used for other disk devices (see disk(7)).

      Data can be stored on flexible disk media in a variety of logical
      formats.	The capacity of these devices is generally too small to hold
      useful HP-UX file systems.  Instead, DOS or LIF file systems (see
      dosif(4) and lif(4) for a detailed description of these file systems)
      are commonly used.  Data can also be stored in an archive-utility
      format.  For example, tar and cpio are commonly used to share data
      with other HP-UX systems (see tar(1) and cpio(1)).

      Logical volumes are not supported on flexible disks.  The floppy disk
      does not support partitions.  Section zero (0) is the only accessible
      partition.

      In addition to the various logical formats, data can be stored on
      flexible disk media in a variety of physical data formats called
      geometries.  The following parameters are used to describe a flexible
      disk geometry:

	   heads	  Number of surfaces (or sides) on the media that
			  contain valid data.

	   tracks	  Number of tracks on a single media surface or side
			  (the term cylinders is sometimes also used).	This
			  value does not include spare tracks.

	   sectors	  Number of sectors in a single track.	The number
			  of sectors that can fit on a track depends on the
			  bit density (as controlled by transfer rate and
			  media rotation rate) and the sector size.

	   sector size	  Number of bytes in a logical sector.	Since all
			  I/O operations must be an integral number of
			  sectors in length, this parameter also indicates
			  the minimum character-special file I/O size.

	   transfer rate  Media data rate in Kbits per second.	The transfer
			  rate is an indirect means of representing bit
			  density.  Bit density is measured in bits per
			  radian, and is the formal intra-track data density
			  parameter for standard specification.	 Transfer
			  rate is generally used to program flexible media



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 floppy(7)							   floppy(7)




			  devices and is therefore more appropriate for this
			  interface.  Since the media rotation rate for most
			  flexible disk devices is standard, conversion
			  between these two representations is straight-
			  forward.

	   track density  Number of tracks per inch.  Some low density
			  formats can be supported on high-density drives by
			  skipping tracks during head stepping.

	   data encoding  Encoding method used to store data.  FM (frequency
			  modulation) and MFM (modified frequency
			  modulation) are the most common encoding methods.

      The following table shows some useful flexible disk media geometries
      (without density information).  The right-most column indicates which
      mediainit -f option should be used to format media to the indicated
      geometry (see mediainit(1M)).

      +--------------+----------+-----------+----+-----+------+------+----+
      | Media Type   |	 Use	|  Capacity | hd | trk | sect | size | -f |
      +--------------+----------+-----------+----+-----+------+------+----+
      | 3.5in DS DD  |		|   630,784 |  2 |  77 |  16  |	 256 |	1 |
      | 3.5in DS DD  |		|   655,360 |  2 |  80 |  16  |	 256 | 21 |
      | 3.5in DS DD  |		|   655,360 |  2 |  80 |   8  |	 512 | 26 |
      | 3.5in DS DD  |		|   709,632 |  2 |  77 |   9  |	 512 |	2 |
      | 3.5in DS DD  | DOS 720K |   737,280 |  2 |  80 |   9  |	 512 | 16 |
      | 3.5in DS DD  |		|   788,480 |  2 |  77 |   5  | 1024 |	3 |
      +--------------+----------+-----------+----+-----+------+------+----+
      | 3.5in DS HD' | DOS 1.2M | 1,228,800 |  2 |  80 |  15  |	 512 | 26 |
      | 3.5in DS HD' |		| 1,261,568 |  2 |  77 |   8  | 1024 | 22 |
      +--------------+----------+-----------+----+-----+------+------+----+
      | 3.5in DS HD  |		| 1,261,568 |  2 |  77 |  32  |	 256 |	1 |
      | 3.5in DS HD  |		| 1,419,264 |  2 |  77 |  18  |	 512 |	2 |
      | 3.5in DS HD  | DOS 1.44M| 1,474,560 |  2 |  80 |  18  |	 512 | 16 |
      | 3.5in DS HD  |		| 1,567,960 |  2 |  77 |  10  | 1024 |	3 |
      | 3.5in DS HD  |		| 1,638,400 |  2 |  80 |  10  | 1024 | 23 |
      +--------------+----------+-----------+----+-----+------+------+----+
      | 5.25in DS    | DOS 360K |   368,640 |  2 |  40 |   9  |	 512 |	2 |
      | 5.25in DS DD |		|   655,360 |  2 |  80 |   8  |	 512 | 26 |
      | 5.25in DS HD | DOS 1.2M | 1,228,800 |  2 |  80 |  15  |	 512 | 16 |
      | 5.25in DS HD |		| 1,261,568 |  2 |  77 |   8  | 1024 | 24 |
      +--------------+----------+-----------+----+-----+------+------+----+


      The following table shows the density information for some standard
      flexible disk media.

      +--------------+----------+-----+------------+-----------+----------+
      | Media Type   | Bit Den	| RPM | Trans Rate | Track Den | Encoding |
      +--------------+----------+-----+------------+-----------+----------+



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 floppy(7)							   floppy(7)




      | 3.5in DS DD  |	  7,958 | 300 |	       250 |	   135 |      MFM |
      | 3.5in DS HD' |	 13,262 | 360 |	       500 |	   135 |      MFM |
      | 3.5in DS HD  |	 15,916 | 300 |	       500 |	   135 |      MFM |
      +--------------+----------+-----+------------+-----------+----------+
      | 5.25in DS    |	  7,958 | 300 |	       250 |	    48 |      MFM |
      | 5.25in DS DD |	  7,958 | 300 |	       250 |	    96 |      MFM |
      | 5.25in DS HD |	 13,262 | 360 |	       500 |	    96 |      MFM |
      +--------------+----------+-----+------------+-----------+----------+


      Abbreviations are interpreted as follows:

	   DS	  Double-sided media
	   DD	  Double-density media
	   HD	  High-density media
	   HD'	  High-density media (alternate media rotation rate)

      Normally each open() call causes the device and/or floppy device
      driver to attempt to determine the geometry of the installed media.
      As a result, the current flexible disk geometry is set to the
      supported geometry that matches the physical data format on the media
      currently installed in the device.  To maintain reasonable open times,
      not all possible media geometries are checked.  Therefore, it is
      possible that a flexible disk medium may contain valid data even
      though its format is not recognized.  This automatic geometry sensing
      functionality may be disabled in some drivers by use of the O_NDELAY
      flag in the open() call or device driver dependent minor numbers. The
      Series 800 does not support this flag.

      The FLOPPY_GET_INFO ioctl indicates the characteristics and current
      status of a floppy device.  Information for interpreting the media and
      data_encoding fields can be found in <sys/floppy.h>.  The following
      macros are defined for decoding the status and valid fields.  These
      macros return a non-zero (true) value for the associated conditions.

	   FLOPPY_NO_MEDIA(x)	    /* Drive is empty */
	   FLOPPY_BLANK_MEDIA(x)    /* Media geometry is not recognizable */
	   FLOPPY_WRITE_PROT(x)	    /* Media is write protected */
	   FLOPPY_MEDIA_CHANGED(x)  /* Media has changed since last status
				    */
	   FLOPPY_HIGH_DENSITY(x)   /* Media has high density indication */

      The argument x in the above macros refers to the status or valid
      fields of the FLOPPY_GET_INFO ioctl.  Some floppy devices or floppy
      device drivers may be unable to determine some status information.
      The valid field indicates whether or not the corresponding status
      information is meaningful.  Applying a macro to the valid field
      indicates whether or not the application of that same macro to the
      status field results in a valid device status.





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 floppy(7)							   floppy(7)




      The FLOPPY_GET_GEOMETRY ioctl can be used to determine the flexible
      disk device's current media geometry.  Current geometry parameters are
      indicated in the fields of the resultant floppy_geometry structure.

      The FLOPPY_SET_GEOMETRY ioctl can be used to specify the desired media
      geometry.	 Exclusive access to the device, obtained through use of the
      DIOC_EXCLUSIVE ioctl (see disk(7)), is required prior to setting the
      media geometry.  Exclusive access is necessary to ensure that other
      applications are not affected.  The Series 800 does not support this
      ioctl.

      The FLOPPY_FORMAT_TRACK ioctl can be used to reformat a media track.
      Exclusive access to the device, obtained through use of the
      DIOC_EXCLUSIVE ioctl (see disk(7)), is required prior to reformatting
      to ensure that other applications are not affected.  The Series 800
      does not support this ioctl.

      Flexible disk devices support the generic disk ioctls (see disk(7)),
      typically used for hard disk devices.  Flexible disk device drivers
      may also support driver specific ioctls (see the appropriate driver
      manual section).

      The header file <sys/floppy.h> has useful information for flexible-
      media device control.  The following is included from <sys/floppy.h>:

      /* ioctls for flexible (floppy) disk devices */
      #define FLOPPY_GET_INFO	      _IOR('F', 1, struct floppy_info)
      #define FLOPPY_GET_GEOMETRY     _IOR('F', 2, struct floppy_geom)
      #define FLOPPY_SET_GEOMETRY     _IOW('F', 3, struct floppy_geom)
      #define FLOPPY_FORMAT_TRACK     _IOW('F', 4, struct floppy_format)

      /* structure for FLOPPY_GET_INFO ioctl */
      struct floppy_info {
	      unsigned	     media;
	      unsigned	     status;
	      unsigned	     valid;
      };

      /* structure for FLOPPY_GET_GEOMETRY and FLOPPY_SET_GEOMETRY ioctls */
      struct floppy_geometry {
	      unsigned	     heads;
	      unsigned	     tracks;
	      unsigned	     sectors;
	      unsigned	     sector_size;
	      unsigned	     transfer_rate;
	      unsigned	     track_density;
	      unsigned	     data_encoding;
      };

      /* structure for FLOPPY_FORMAT_TRACK ioctl */
      struct floppy_format {



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 floppy(7)							   floppy(7)




	      unsigned	     head;
	      unsigned	     track;
	      unsigned	     interleave;
      };

 ERRORS
      The following errors can be returned by a flexible-disk device-driver
      call:

	   [EACCES]	  Required permission is denied for the the device
			  or operation.

	   [ENXIO]	  If resulting from an open call, this indicates
			  there is no device at the specified address.	For
			  other calls, this indicates the specified address
			  is out of range or the device can no longer be
			  accessed.

	   [EINVAL]	  From an open() call: the device is not a floppy
			  device.  For other calls: Invalid request or
			  parameter.

	   [EIO]	  I/O error (e.g., media defect or device
			  communication problem).

 WARNING
      Media removal and/or replacement while the device is open is not
      supported.  A floppy disk containing a mounted file system should not
      be removed prior to being unmounted.  Removal of floppy disks
      containing mounted file systems is likely to result in file system
      errors, and system panics.

      Reformatting flexible disk media from one geometry to another that
      differs only in that it has fewer tracks can cause the automatic
      geometry sensing functionality of open() to fail to recognize the new
      media geometry.  Bulk erasing (degaussing) the media or formatting the
      media to a substantially different geometry prior to reformatting
      prevents automatic geometry sensing problems.

      Single track formatting may not be supported by some floppy devices.

      Some devices permit configuration for geometries which they are unable
      to support.  The FLOPPY_SET_GEOMETRY ioctl for such a configuration
      may not result in an error.  However, subsequent I/O operations will
      fail.

 DEPENDENCIES
    Series 700
      Series 700 device special files reside in the directories /dev/rfloppy
      and /dev/floppy.




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 floppy(7)							   floppy(7)




    Series 800
      A flexible disk can be opened with no media. However, capacity changes
      resulting from subsequent media changes will not be recognized. (See
      scsi_disk(7)).

      Series 800 device special files reside in the directories /dev/rdsk
      and /dev/dsk.

      The following table of Series 800 Flexible Disk Media shows the disk
      geometries supported.  The media inserted in the drive is formatted
      depending on the presence or absence of the HD hole in the flexible
      disk cartridge.  HD media is formatted as a 1.44M diskette and DD
      media is formatted as a 720K diskette.

      +--------------+----------+-----------+----+-----+------+------+
      | Media Type   |	 Use	|  Capacity | hd | trk | sect | size |
      +--------------+----------+-----------+----+-----+------+------+
      | 3.5in DS DD  | DOS 720K |   737,280 |  2 |  80 |   9  |	 512 |
      +--------------+----------+-----------+----+-----+------+------+
      | 3.5in DS HD  | DOS 1.44M| 1,474,560 |  2 |  80 |  18  |	 512 |
      +--------------+----------+-----------+----+-----+------+------+


      The following table shows the density information for the flexible
      disk media supported:

      +--------------+----------+-----+------------+-----------+----------+
      | Media Type   | Bit Den	| RPM | Trans Rate | Track Den | Encoding |
      +--------------+----------+-----+------------+-----------+----------+
      | 3.5in DS DD  |	  7,958 | 300 |	       250 |	   135 |      MFM |
      | 3.5in DS HD  |	 15,916 | 300 |	       500 |	   135 |      MFM |
      +--------------+----------+-----+------------+-----------+----------+


      The FLOPPY_GET_INFO and FLOPPY_GET_GEOMETRY ioctls are supported on
      Series 800.

 SEE ALSO
      disk(7), mediainit(1), mknod(1M), dosif(4), lif(4), scsi(7),
      scsi_disk(7).














 Hewlett-Packard Company	    - 6 -   HP-UX Release 11i: November 2000