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Annotation of coherent/a/usr/man/COHERENT/fd, revision 1.1

1.1     ! root        1: 
        !             2: 
        !             3: fd                        Device Driver                        fd
        !             4: 
        !             5: 
        !             6: 
        !             7: 
        !             8: Floppy disk driver
        !             9: 
        !            10: 
        !            11: The files /dev/f* are entries for the diskette drives of COHERENT
        !            12: on the IBM AT.  Each entry  is assigned major device number 4, is
        !            13: accessed  as  a block-special  device,  and  has a  corresponding
        !            14: character-special device entry.
        !            15: 
        !            16: The device entries are linked to a driver that handles up to four
        !            17: 5.25  inch disk  drives,  each in  one of  several formats.   The
        !            18: least-significant  four bits  of an  entry's minor  device number
        !            19: identify the type  of drive.  The next least-significant two bits
        !            20: identify  the drive.   The following  table summarizes  the name,
        !            21: minor device  number, sectors  per track, partition  sector size,
        !            22: characteristics, and  addressing method for each  device entry of
        !            23: floppy disk drive 0.
        !            24: 
        !            25: 
        !            26:      _9 _s_e_c_t_o_r_s/_t_r_a_c_k
        !            27: 
        !            28:      ff99dd00    4    9   720   DSDD   surface (5.25 inch)
        !            29:      ffqqaa00   13    9  1440   DSQD   cylinder (3.25 inch)
        !            30:      ff99aa00   12    9   720   DSDD   cylinder (5.25 inch)
        !            31: 
        !            32: 
        !            33: 
        !            34:      _1_5 _s_e_c_t_o_r_s/_t_r_a_c_k
        !            35: 
        !            36:      ffhhaa00   14   15  2400   DSHD   cylinder (5.25 inch)
        !            37: 
        !            38: 
        !            39: 
        !            40:      _1_8 _s_e_c_t_o_r_s/_t_r_a_c_k
        !            41: 
        !            42:      ffvvaa00   15   18  2880   DSHD   cylinder
        !            43: 
        !            44: 
        !            45: 
        !            46: Prefixing an r  to a name given above gives  the name of the cor-
        !            47: responding character-device  entry.  Corresponding device entries
        !            48: for drives 1, 2, and 3 have minor numbers with offsets of 16, 32,
        !            49: and 48 from the minor numbers  given above and have 1, 2, or 3 in
        !            50: place of 0 in the names given above.
        !            51: 
        !            52: For device entries  whose minor number's fourth least-significant
        !            53: bit is zero  (minor numbers 0 through 7 for  drive 0), the driver
        !            54: uses  surface addressing rather  than cylinder  addressing.  This
        !            55: means that it  increments tracks before heads when computing sec-
        !            56: tor addresses  and  the first  surface is used  completely before
        !            57: the second surface is accessed.  For devices whose minor number's
        !            58: fourth least significant bit is 1 (minor numbers 8 through 15 for
        !            59: drive 0), the driver uses cylinder addressing.
        !            60: 
        !            61: 
        !            62: 
        !            63: 
        !            64: COHERENT Lexicon                                           Page 1
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        !            66: 
        !            67: 
        !            68: 
        !            69: fd                        Device Driver                        fd
        !            70: 
        !            71: 
        !            72: 
        !            73: For  a diskette  to  be accessible  from the  COHERENT system,  a
        !            74: device  file  must be  present  in directory  /dev  with the  ap-
        !            75: propriate type, major  and minor device numbers, and permissions.
        !            76: The command mknod creates a special file for a device.
        !            77: 
        !            78: ***** Files *****
        !            79: 
        !            80: <ffddiiooccttll.hh> -- Driver command header file
        !            81: /ddeevv/ffdd* -- Block-special files
        !            82: /ddeevv/rrffdd* -- Character special files
        !            83: 
        !            84: ***** See Also *****
        !            85: 
        !            86: device drivers, fdformat, mkfs, mknod,
        !            87: 
        !            88: ***** Diagnostics *****
        !            89: 
        !            90: The driver reports  any error status received from the controller
        !            91: and retries the operation  several times before it reports an er-
        !            92: ror to the program that initiated an operation.
        !            93: 
        !            94: ***** Notes *****
        !            95: 
        !            96: The driver  assumes that the disk is  formatted with eight, nine,
        !            97: 15, or 18 sectors of 512 bytes each per track, depending upon the
        !            98: /ddeevv entry.  Cylinder addressing is the norm for COHERENT.
        !            99: 
        !           100: Programs that  use the raw device interface  must read whole sec-
        !           101: tors into buffers that do not straddle DMA boundaries.
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        !           129: 
        !           130: COHERENT Lexicon                                           Page 2
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