300(1) 300(1)NAME 300, 300s - filter text containing printer control sequences for a DASI terminal SYNOPSIS 300 [+12] [-n] [-dt,l,c] 300s [+12] [-n] [-dt,l,c] DESCRIPTION 300 supports special functions and optimizes the use of the DASI 300 (GSI 300 or DTC 300) terminal; 300s performs the same functions for the DASI 300s (GSI 300s or DTC 300s) ter- minal. It converts half-line forward, half-line reverse, and full-line reverse motions to the correct vertical mo- tions. It also attempts to draw Greek letters and other special symbols. It permits convenient use of 12-pitch text. It also reduces printing time 5 to 70%. 300 can be used to print equations neatly, in the sequence: neqn file... | nroff | 300 WARNING: if your terminal has a PLOT switch, make sure it is turned ON before 300 is used. The behavior of 300 can be modified by the optional flag ar- guments to handle 12-pitch text, fractional line spacings, messages, and delays. +12 permits use of 12-pitch, 6 lines/inch text. DASI 300 terminals normally allow only two combinations: 10-pitch, 6 lines/inch, or 12-pitch, 8 lines/inch. To obtain the 12-pitch, 6 lines per inch combina- tion, the user should turn the PITCH switch to 12, and use the +12 option. -n controls the size of half-line spacing. A half- line is, by default, equal to 4 vertical plot in- crements. Because each increment equals 1/48 of an inch, a 10-pitch line-feed requires 8 increments, while a 12-pitch line-feed needs only 6. The first digit of n overrides the default value, thus allow- ing for individual taste in the appearance of sub- scripts and superscripts. For example, nroff half-lines could be made to act as quarter-lines by using -2. The user could also obtain appropriate half-lines for 12-pitch, 8 lines/inch mode by using the option -3 alone, having set the PITCH switch to 12-pitch. -dt,l,c controls delay factors. The default setting is - April, 1990 1
300(1) 300(1)d3,90,30. DASI 300 terminals sometimes produce peculiar output when faced with very long lines, too many tab characters, or long strings of blank- less, nonidentical characters. One null (delay) character is inserted in a line for every set of t tabs and for every contiguous string of c nonblank, nontab characters. If a line is longer than l bytes, 1+(total length)/20 nulls are inserted at the end of that line. Items can be omitted from the end of the list, implying use of the default values. Also, a value of zero for t (c) results in two null bytes per tab (character). The former may be needed for C programs, the latter for files like /etc/passwd. Because terminal behavior varies ac- cording to the specific characters printed and the load on a system, the user may have to experiment with these values to get correct output. The -d option exists only as a last resort for those few cases that do not otherwise print properly. For example, the file /etc/passwd may be printed using -d3,30,5. The value -d0,1 is a good one to use for C programs that have many levels of indentation. Note that the delay control interacts heavily with the prevailing carriage return and line-feed de- lays. The stty(1) modes nl0 cr2 or nl0 cr3 are recommended for most uses. 300 can be used with the nroff -s flag or .rd requests, when it is necessary to insert paper manually or change fonts in the middle of a document. Instead of hitting the RETURN key in these cases, you must use the line-feed key to get any response. In many (but not all) cases, the following two command lines are equivalent: nroff -T300 files nroff files | 300 Similarly, in many (but not all) cases, the following two command lines are equivalent: nroff -T300 -12 files nroff files | 300 +12 The use of 300 can thus often be avoided unless special de- lays or options are required; in a few cases, however, the additional movement optimization of 300 may produce better- aligned output. 2 April, 1990
300(1) 300(1)The neqn names of and resulting output for the Greek and special characters supported by 300 are shown in greek(5). FILES /usr/bin/300 /usr/bin/300s SEE ALSO 450(1), eqn(1), mesg(1), nroff(1), stty(1), tabs(1), tbl(1), tplot(1G), greek(5). BUGS Some special characters cannot be correctly printed in column 1 because the print head cannot be moved to the left from there. If your output contains Greek or reverse line-feeds, use a friction-feed platen instead of a forms tractor; although good enough for drafts, the latter has a tendency to slip when reversing direction, distorting Greek characters and misaligning the first line of text after one or more reverse line-feeds. April, 1990 3