[rescue] Vector Plotters

[Richard]

In article <5612B186.3040402 at rcn.com>,
    "Carl R. Friend" <crfriend at rcn.com> writes:

>     Vector CRTs, however do exist and typically, but not always,
> make use of storage-tubes for the display.  These are capable of
> producing perfectly true curves, but are long obsolete.

Just a small nit to pick: vector displays are capable of producing
true lines, but most will not draw true curves.  Curves are broken down
into polyline approximations and send to the tube as a series of vectors.

ISTR that there were some early analog oriented displays that could
draw some subsets of curves by encoding the "formula" for the curve as
an analog voltage from a specific circuit, but this was quickly
abandoned in favor of approximating the curve as a series of vector
segments.
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