The PDP-3 Cathode Ray Tube Display is useful for presentation of
graphical or tabular information to the operator. It uses a 16 inch
round tube with magnetic deflection. For each In-Out transfer order, one
point is displayed at the position indicated by the In-Out Register.
Bits 0-9 of the IO indicate the X coordinate of the position, and bits
18-27 indicate the Y coordinate. The display takes 60 microseconds.
An additional display option is a Light Pen. By use of this device the
computer is signaled that the operator is interested in the last point
displayed. Thus the program can take appropriate action such as changing
the display or shifting operation to another program.
A smaller display is available. This display uses a five inch, high
resolution cathode ray tube. The tube is equipped with a mounting bezel
to accept a camera or photomultiplier device. The operation of this
display is similar to that of the 16 inch, except that 12 bits are
decoded for each axis.