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Diffstat (limited to 'static/unix-v10/man4/vt.4')
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diff --git a/static/unix-v10/man4/vt.4 b/static/unix-v10/man4/vt.4 new file mode 100644 index 00000000..a74d00c2 --- /dev/null +++ b/static/unix-v10/man4/vt.4 @@ -0,0 +1,230 @@ +.pa 1 +.he 'VT (IV)'2/11/73'VT (IV)' +.ti 0 +NAME vt -- 11/20 (vt01) interface +.sp +.ti 0 +DESCRIPTION +.br +.in 8 +The file vt0___ provides +the interface to a PDP 11/20 which +runs both a VT01A-controlled Tektronix 611 +storage display, +and a Federal Screw Works (Vocal Interface Division) +voice synthesizer. +The inter-computer interface is +a pair of DR-11C word interfaces. + +Although the display has essentially only two commands, +namely "erase screen" and "display point", the 11/20 program +will draw points, lines, and arcs, and print +text on the screen. +The 11/20 can also type information +on the attached 33 TTY and generate utterances via the +voice synthesizer. + +This special file operates in two basic modes, selected +by bit 2 (octal 04) on the 11/20's console switches. +If this bit is on at the opening of the file, +all bytes written on the file are interpreted as ASCII characters +and written on the screen. +The screen has 33 lines (1/2 a standard page). +The file simulates a 37 TTY: the control characters +NL, CR, BS, and TAB are interpreted correctly. +It also interprets the usual escape sequences +for forward and reverse half-line motion and for +full-line reverse. +Greek is not available yet. +Normally, when the screen is full (i.e. the 34th line is started) +the screen is erased before starting a new page. +To allow perusal of the displayed text, it is usual to +assert bit 0 of the console switches (octal 01). +As explained below, this causes the program to +pause before erasing until one of the attached pushbuttons +is depressed. + +If bit 2 of the switches is down, the display is in graphic +mode. +In this case bytes written on the file +are interpreted as display and vocal +commands. +Each command consists of a single byte usually followed +by parameter bytes. +Often the parameter bytes represent +points in the plotting area. +Each point coordinate consists of 2 bytes +interpreted as a 2's complement 16-bit number. +The plotting area itself measures (+_03777)X(+_03777) +(numbers in octal); +that is, 12 bits of precision. +Attempts to plot +points outside the screen limits are ignored. + +The graphic and sonic commands are: + +.in +5 +.ti -5 +order (1); 1 parameter byte +.br +The parameter indicates a subcommand, possibly followed +by subparameter bytes, as follows: +.in +5 + +.ti -5 +erase (1) +.br +The screen is erased. +This action may be delayed, as explained below, +until a pushbutton is depressed. + +.ti -5 +label (2); several subparameter bytes +.br +The following bytes up to a null character +are taken as a label and typed on the console TTY. +One of the console switches gives labels +a special interpretation, as explained below. + +.ti -5 +.nf +display label (3); several subparameter bytes +.fi +.br +The following bytes up to a null byte are printed +as ASCII text on the screen. +The origin of the text is the last previous point +plotted; or the upper left hand of the screen if there were none. + +.in -5 +.ti -5 +point (2); 4 parameter bytes +.br +The 4 parameter bytes are taken as a pair of coordinates +representing a point to be plotted. + +.ti -5 +line (3); 8 parameter bytes +.br +The parameter bytes are taken as 2 pairs of coordinates +representing the ends of a line segment which is plotted. +Only the portion lying within the screen is displayed. + +.ti -5 +frame (4); 1 parameter byte +.br +The parameter byte is taken as a number of sixtieths of a second; +an externally-available lead is asserted for that time. +Typically the lead is connected to +an automatic camera +which advances its film and opens the +shutter for the specified time. + +.ti -5 +circle (5); 6 parameter bytes +.br +The parameter bytes are taken as a coordinate pair representing +the origin, and a word representing the radius of a circle. +That portion of the circle which lies within the screen is plotted. + +.ti -5 +arc (6); 12 parameter bytes +.br +The first 4 parameter bytes are taken to be a coordinate-pair +representing the center of a circle. +The next 4 represent a coordinate-pair specifying a point +on this circle. +The last 4 should represent another point on the +circle. +An arc is drawn counter-clockwise from the first circle point +to the second. +If the two points are the same, the whole circle is drawn. +For the second point, only the smaller in magnitude +of its two coordinates is significant; +the other is used only to find the quadrant of the end of the arc. +In any event only points within the screen limits are +plotted. + +.ti -5 +dot-line (7); at least 6 parameter bytes +.br +The first 4 parameter bytes are taken +as a coordinate-pair representing the origin +of a dot-line. +The next byte is taken as a signed +x-increment. +The next byte is an unsigned word-count, +with "0" meaning "256". +The indicated +number of words is picked up. +For each bit in each word a point is plotted +which is visible if the bit is "1", invisible +if not. +High-order bits are plotted first. +Each successive point (or non-point) is offset +rightward by the given x-increment. + +.ti -5 +speak(8); several parameter bytes +.br +The following bytes up to a null byte are taken +to represent phonemes which are fed to +the voice synthesizer. +vsp(VII) gives the encoding. + +.in -5 +The 3 low-order console switches of the 11/20 +modify the operation of the display as follows. + +Bit 2 (octal 04) is examined at the time the display +file is opened (more precisely, when the first byte +is written after an open); as indicated, +when on__ it selects character mode, otherwise graphic +mode. + +Bit 1 (octal 02) +determines whether TTY labels are to be interpreted. +Unless this bit is on__, labels are ignored. +(except to terminate skip mode, see below). + +Bit 0 (octal 01) determines +whether the display will pause before erasing +the screen; +if off___ there will be no pause. +.a +If bit 0 is on__, the erase will occur +and displaying will resume only when one of the +16 pushbuttons is depressed. + +There is a box with 16 pushbuttons connected +to the 11/20. +Their state is at all times available in the 11/45 +by executing the csw___ system call (II). +They are used by the 11/20 when it is pausing +before an erase. +14 of the buttons merely serve to allow the display +to continue. +If, however, button 7 +is pushed, +the display will ignore commands up to the +next erase command, then ring the TTY console's bell, +thereby skipping an entire picture. + +If button 8 is depressed, +the display will ignore commands up to the next TTY label +(whether or not its typing is suppressed) before +resuming the displays. +Thus a sequence of frames may be skipped. +.sp +.in 16 +.ti 0 +FILES /dev/vt0 +.sp +.ti 0 +SEE ALSO csw(II), vsp(VII) +.sp +.ti 0 +BUGS Two +users using vt0 simultaneously +can interfere with each other, +e.g. plot phonemes or speak display coordinates. |