Return to vt.4 CVS log

Up to [Research Unix] / researchv10dc / dist / man / v4 / man4

Annotation of researchv10dc/dist/man/v4/man4/vt.4, revision 1.1

1.1     ! root        1: .th VT IV 10/22/73
        !             2: .sh NAME
        !             3: vt \*- 11/20 (vt01) interface
        !             4: .sh DESCRIPTION
        !             5: The file
        !             6: .it vt0
        !             7: provides
        !             8: the interface to a PDP 11/20 which
        !             9: runs a VT01A-controlled Tektronix 611
        !            10: storage display.
        !            11: The inter-computer interface is
        !            12: a pair of DR-11C word interfaces.
        !            13: .s3
        !            14: Although the display has essentially only two commands,
        !            15: namely ``erase screen'' and ``display point'', the 11/20 program
        !            16: will draw points, lines, and arcs, and print
        !            17: text on the screen.
        !            18: The 11/20 can also type information
        !            19: on the attached 33 TTY.
        !            20: .s3
        !            21: This special file operates in two basic modes.
        !            22: If the first byte written of the file
        !            23: cannot be interpreted as one of the codes discussed below,
        !            24: the rest of the transmitted
        !            25: information is assumed to ASCII and
        !            26: written on the screen.
        !            27: The screen has 33 lines (1/2 a standard page).
        !            28: The file simulates a 37 TTY: the control characters
        !            29: NL, CR, BS, and TAB are interpreted correctly.
        !            30: It also interprets the usual escape sequences
        !            31: for forward and reverse half-line motion and for
        !            32: full-line reverse.
        !            33: Greek is not available yet.
        !            34: Normally, when the screen is full (i.e. the 34th line is started)
        !            35: the screen is erased before starting a new page.
        !            36: To allow perusal of the displayed text, it is usual to
        !            37: assert bit 0 of the console switches.
        !            38: This causes the program to
        !            39: pause before erasing until this bit is lowered.
        !            40: .s3
        !            41: If the first byte written is recognizable, the display runs in graphic
        !            42: mode.
        !            43: In this case bytes written on the file
        !            44: are interpreted as display
        !            45: commands.
        !            46: Each command consists of a single byte usually followed
        !            47: by parameter bytes.
        !            48: Often the parameter bytes represent
        !            49: points in the plotting area.
        !            50: Each point coordinate consists of 2 bytes
        !            51: interpreted as a 2's complement 16-bit number.
        !            52: The plotting area itself measures (\(+-03777)\*X(\(+-03777)
        !            53: (numbers in octal);
        !            54: that is, 12 bits of precision.
        !            55: Attempts to plot
        !            56: points outside the screen limits are ignored.
        !            57: .s3
        !            58: The graphic commands follow.
        !            59: .s3
        !            60: .lp  +10 5
        !            61: order (1); 1 parameter byte
        !            62: .br
        !            63: The parameter indicates a subcommand, possibly followed
        !            64: by subparameter bytes, as follows:
        !            65: .s3
        !            66: .lp +15 5
        !            67: erase (1)
        !            68: .br
        !            69: The screen is erased.
        !            70: The program will wait until
        !            71: bit 0 of the console switches is down.
        !            72: .s3
        !            73: .lp +15 5
        !            74: label (3); several subparameter bytes
        !            75: .fi
        !            76: .br
        !            77: The following bytes up to a null byte are printed
        !            78: as ASCII text on the screen.
        !            79: The origin of the text is the last previous point
        !            80: plotted; or the upper left hand of the screen if there were none.
        !            81: .s3
        !            82: .lp +10 5
        !            83: point (2); 4 parameter bytes
        !            84: .br
        !            85: The 4 parameter bytes are taken as a pair of coordinates
        !            86: representing a point to be plotted.
        !            87: .s3
        !            88: .lp +10 5
        !            89: line (3); 8 parameter bytes
        !            90: .br
        !            91: The parameter bytes are taken as 2 pairs of coordinates
        !            92: representing the ends of a line segment which is plotted.
        !            93: Only the portion lying within the screen is displayed.
        !            94: .s3
        !            95: .lp +10 5
        !            96: frame (4); 1 parameter byte
        !            97: .br
        !            98: The parameter byte is taken as a number of sixtieths of a second;
        !            99: an externally-available lead is asserted for that time.
        !           100: Typically the lead is connected to
        !           101: an automatic camera
        !           102: which advances its film and opens the
        !           103: shutter for the specified time.
        !           104: .s3
        !           105: .lp +10 5
        !           106: circle (5); 6 parameter bytes
        !           107: .br
        !           108: The parameter bytes are taken as a coordinate pair representing
        !           109: the origin, and a word representing the radius of a circle.
        !           110: That portion of the circle which lies within the screen is plotted.
        !           111: .s3
        !           112: .lp +10 5
        !           113: arc (6); 12 parameter bytes
        !           114: .br
        !           115: The first 4 parameter bytes are taken to be a coordinate-pair
        !           116: representing the center of a circle.
        !           117: The next 4 represent a coordinate-pair specifying a point
        !           118: on this circle.
        !           119: The last 4 should represent another point on the
        !           120: circle.
        !           121: An arc is drawn counter-clockwise from the first circle point
        !           122: to the second.
        !           123: If the two points are the same, the whole circle is drawn.
        !           124: For the second point, only the smaller in magnitude
        !           125: of its two coordinates is significant;
        !           126: the other is used only to find the quadrant of the end of the arc.
        !           127: In any event only points within the screen limits are
        !           128: plotted.
        !           129: .s3
        !           130: .lp +10 5
        !           131: dot-line (7); at least 6 parameter bytes
        !           132: .br
        !           133: The first 4 parameter bytes are taken
        !           134: as a coordinate-pair representing the origin
        !           135: of a dot-line.
        !           136: The next byte is taken as a signed
        !           137: x-increment.
        !           138: The next byte is an unsigned word-count,
        !           139: with `0' meaning `256'.
        !           140: The indicated
        !           141: number of words is picked up.
        !           142: For each bit in each word a point is plotted
        !           143: which is visible if the bit is `1', invisible
        !           144: if not.
        !           145: High-order bits are plotted first.
        !           146: Each successive point (or non-point) is offset
        !           147: rightward by the given x-increment.
        !           148: .s3
        !           149: .i0
        !           150: Asserting bit 3 of the console switches
        !           151: causes the display processor to throw away everything written on it.
        !           152: This sometimes helps if the display seems to be hung up.
        !           153: .sh FILES
        !           154: /dev/vt0
        !           155: .sh BUGS

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.