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Annotation of 43BSDTahoe/man/man4/vax/mtio.4, revision 1.1

1.1     ! root        1: .\" Copyright (c) 1983 Regents of the University of California.
        !             2: .\" All rights reserved.  The Berkeley software License Agreement
        !             3: .\" specifies the terms and conditions for redistribution.
        !             4: .\"
        !             5: .\"    @(#)mtio.4      6.2 (Berkeley) 5/16/86
        !             6: .\"
        !             7: .TH MTIO 4 "May 16, 1986"
        !             8: .UC 5
        !             9: .SH NAME
        !            10: mtio \- UNIX magtape interface
        !            11: .SH DESCRIPTION
        !            12: The files
        !            13: .I "mt0, ..., mt15"
        !            14: refer to the UNIX magtape drives,
        !            15: which may be on the MASSBUS using the TM03 formatter
        !            16: .IR ht (4),
        !            17: or TM78 formatter,
        !            18: .IR mt (4),
        !            19: or on the UNIBUS using either the TM11 or TS11 formatters
        !            20: .IR tm (4),
        !            21: TU45 compatible formatters,
        !            22: .IR ut (4),
        !            23: or
        !            24: .IR ts (4).
        !            25: The following description applies to any of the transport/controller pairs.
        !            26: The files
        !            27: .I "mt0, ..., mt7"
        !            28: are 800bpi (or the transport's lowest density), 
        !            29: .I "mt8, ..., mt15"
        !            30: are 1600bpi (or the transport's second density), and
        !            31: .I "mt16, ..., mt23"
        !            32: are 6250bpi (or the transport's third density).
        !            33: (But note that only 1600 bpi is available with the TS11.)
        !            34: The files
        !            35: .IR "mt0, ..., mt3" ,
        !            36: .IR "mt8, ..., mt11" ,
        !            37: and
        !            38: .I "mt16, ..., mt19"
        !            39: are rewound when closed; the others are not.
        !            40: When a file open for writing is closed, two end-of-files are written.
        !            41: If the tape is not to be rewound
        !            42: it is positioned with the head between the two
        !            43: tapemarks.
        !            44: .PP
        !            45: A standard tape consists of a
        !            46: series of 1024 byte records terminated by an
        !            47: end-of-file.
        !            48: To the extent possible, the system makes
        !            49: it possible, if inefficient, to treat
        !            50: the tape like any other file.
        !            51: Seeks have their usual meaning and it is possible
        !            52: to read or write a byte at a time.
        !            53: Writing in very small units is inadvisable,
        !            54: however, because it uses most of the tape in record
        !            55: gaps.
        !            56: .PP
        !            57: The
        !            58: .I mt
        !            59: files discussed above are useful
        !            60: when it is desired to access the tape in a way
        !            61: compatible with ordinary files.
        !            62: When foreign tapes are to be dealt with, and especially
        !            63: when long records are to be read or written, the
        !            64: `raw' interface is appropriate.
        !            65: The associated files are named
        !            66: .I "rmt0, ..., rmt23,"
        !            67: but the same minor-device considerations as for the regular files still apply.
        !            68: A number of other ioctl operations are available
        !            69: on raw magnetic tape.
        !            70: The following definitions are from
        !            71: .RI < sys/mtio.h >:
        !            72: .PP
        !            73: .nf
        !            74: /*
        !            75:  * Structures and definitions for mag tape io control commands
        !            76:  */
        !            77: 
        !            78: /* structure for MTIOCTOP - mag tape op command */
        !            79: struct mtop    {
        !            80:        short   mt_op;          /* operations defined below */
        !            81:        daddr_t mt_count;       /* how many of them */
        !            82: };
        !            83: 
        !            84: /* operations */
        !            85: #define MTWEOF 0       /* write an end-of-file record */
        !            86: #define MTFSF  1       /* forward space file */
        !            87: #define MTBSF  2       /* backward space file */
        !            88: #define MTFSR  3       /* forward space record */
        !            89: #define MTBSR  4       /* backward space record */
        !            90: #define MTREW  5       /* rewind */
        !            91: #define MTOFFL 6       /* rewind and put the drive offline */
        !            92: #define MTNOP  7       /* no operation, sets status only */
        !            93: #define MTCACHE        8       /* enable controller cache */
        !            94: #define MTNOCACHE      9       /* disable controller cache */
        !            95: 
        !            96: /* structure for MTIOCGET - mag tape get status command */
        !            97: 
        !            98: struct mtget   {
        !            99:        short   mt_type;        /* type of magtape device */
        !           100: /* the following two registers are grossly device dependent */
        !           101:        short   mt_dsreg;       /* ``drive status'' register */
        !           102:        short   mt_erreg;       /* ``error'' register */
        !           103: /* end device-dependent registers */
        !           104:        short   mt_resid;       /* residual count */
        !           105: /* the following two are not yet implemented */
        !           106:        daddr_t mt_fileno;      /* file number of current position */
        !           107:        daddr_t mt_blkno;       /* block number of current position */
        !           108: /* end not yet implemented */
        !           109: };
        !           110: 
        !           111: /*
        !           112:  * Constants for mt_type byte.  These are the same
        !           113:  * for other controllers compatible with the types listed.
        !           114:  */
        !           115: #define        MT_ISTS         0x01            /* TS-11 */
        !           116: #define        MT_ISHT         0x02            /* TM03 Massbus: TE16, TU45, TU77 */
        !           117: #define        MT_ISTM         0x03            /* TM11/TE10 Unibus */
        !           118: #define        MT_ISMT         0x04            /* TM78/TU78 Massbus */
        !           119: #define        MT_ISUT         0x05            /* SI TU-45 emulation on Unibus */
        !           120: #define        MT_ISCPC        0x06            /* SUN */
        !           121: #define        MT_ISAR         0x07            /* SUN */
        !           122: #define        MT_ISTMSCP      0x08            /* DEC TMSCP protocol (TU81, TK50) */
        !           123: 
        !           124: /* mag tape io control commands */
        !           125: #define        MTIOCTOP        _IOW(m, 1, struct mtop)         /* do a mag tape op */
        !           126: #define        MTIOCGET        _IOR(m, 2, struct mtget)        /* get tape status */
        !           127: #define MTIOCIEOT      _IO(m, 3)                       /* ignore EOT error */
        !           128: #define MTIOCEEOT      _IO(m, 4)                       /* enable EOT error */
        !           129: 
        !           130: #ifndef KERNEL
        !           131: #define        DEFTAPE "/dev/rmt12"
        !           132: #endif
        !           133: .fi
        !           134: .ft R
        !           135: .PP
        !           136: Each
        !           137: .I read
        !           138: or
        !           139: .I write
        !           140: call reads or writes the next record on the tape.
        !           141: In the write case the record has the same length as the
        !           142: buffer given.
        !           143: During a read, the record size is passed
        !           144: back as the number of bytes read, provided it is no greater
        !           145: than the buffer size;
        !           146: if the record is long, an error is indicated.
        !           147: In raw tape I/O seeks are ignored.
        !           148: A zero byte count is returned when a tape mark is read,
        !           149: but another read will fetch the first record of the
        !           150: new tape file.
        !           151: .SH FILES
        !           152: /dev/mt?
        !           153: .br
        !           154: /dev/rmt?
        !           155: .SH "SEE ALSO"
        !           156: mt(1),
        !           157: tar(1),
        !           158: tp(1),
        !           159: ht(4),
        !           160: tm(4),
        !           161: ts(4),
        !           162: mt(4),
        !           163: ut(4)
        !           164: .SH BUGS
        !           165: The status should be returned in a device independent format.
        !           166: .PP
        !           167: The special file naming should be redone in a more consistent and
        !           168: understandable manner.

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