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The installation of <PLOT79> on the Chemistry DEC VAX-11/780 in January resulted in a new device interface for the Tektronix 4663 pen plotter. This plotter has 2 pens and a respectable 10 inch/second drawing speed, with a C size drawing surface (about 17 in x 22 in, with available drawing area 15.5 in x 20 in), optional paper feed attachment, X-on/X-off protocol, and a large number of switch-settable options for pen pressure, speed, and type, paper format, aspect ratio adjustment, mirror imaging, and so on. The 4663 has a list price of about $11K. Regrettably, the plotter has two serious misfeatures. First of all, although it accepts the normal Tektronix command format used for the 401x storage-tube terminal series, it must first be "selected" by a special command sequence, which it must receive on its serial line, not via its wonderous bank of option switches. Thus, it is not possible to directly send it a plot file produced from one of the 401x interfaces. The alternative of always sending it two plot files, one with the select sequence, and one with the plot commands, is too much of a burden on the user (although an output spooling system could easily manage it). Also, use of the 401x interface does not permit access to the pen change commands. The second misfeature is the great difficulty in setting the plot size. The 4663 automatically rescales the 401x device coordinates (0..1023 or 0..4095) to whatever the viewport is currently set at according to the option switches and corner positions set by the joystick. The switches allow selecting the large C size format, an intermediate B size, and the American standard A size (8.5 x 11 in). Unfortunately, the plotter puts the viewport somewhat inside each of the paper sizes; in the case of the A size, a 10.5 x 7.74 in area is available. The aspect ratio of the B size is different from that of the A and C sizes, which results in a plot which fit in the A or C size being clipped in the B size. The forced margins in each of the paper sizes prevent use of the full page, and the possible arbitrary positioning of the viewport via joystick action make it exceedingly difficult to make a plot of a specified size. We wasted many hours attempting to find the magic combination of events which would let us guarantee the production of a synthetic spectrum plot of exactly the right size to overlay an experimental one. In fairness, the 4663 DOES have a mode in which coordinates can be transmitted in millimeters, but then a totally different software interface is required. The Tektronix 4663 has a little brother, the 4662 (list price about $4600), which has a 8.5 x 11 inch surface, with the available plotting area again somewhat inside this. Once again, joystick positioning of the viewport makes it almost impossible to guarantee the production of a plot in a desired aspect ratio and scale. The 4662 lacks the X-on/X-off protocol, so driving it at an acceptable speed without buffer overflow requires a painful tuning process. Despite claims in the manual to compatibility with the 401x terminal plot commands, we found that it raises an error condition on finding the padding NULs in the 401x plot files which are necessary to prevent data loss on the screen terminals. It has thus been necessary to write a special copy utility which discards NULs and periodically takes a short nap to avoid overflowing the 4662 buffer. The 4662 does accept an alternate command format in which checksummed blocks of commands are sent and acknowledged, but use of this would require yet another device interface. Altogether, I find both of these plotters rather disappointing and annoyingly poorly human engineered.