  Traditional radio telescopes use large, steel dishes to observe radio
sources. The LOFAR radio telescope is different, and uses tens of thousands of
fixed, non-movable antennas instead, a novel design that promises
ground-breaking research in astronomy. The antennas observe omnidirectionally,
and sky sources are observed by signal-processing techniques that combine the
data from all antennas.
  Another new feature of LOFAR is the elaborate use of software to do signal
processing in real time, where traditional telescopes use custom-built
hardware. The use of software leads to an instrument that is inherently more
flexible. However, the enormous data rate (198 Gb/s of input data) and
processing requirements compel the use of a supercomputer: we use an IBM Blue
Gene/P.
  This paper presents a collection of new processing pipelines, collectively
called the beam-forming pipelines, that greatly enhance the functionality of
the telescope. Where our first pipeline could only correlate data to create sky
images, the new pipelines allow the discovery of unknown pulsars, observations
of known pulsars, and (in the future), to observe cosmic rays and study
transient events. Unlike traditional telescopes, we can observe in hundreds of
directions simultaneously. This is useful, for example, to search the sky for
new pulsars. The use of software allows us to quickly add new functionality and
to adapt to new insights that fully exploit the novel features and the power of
our unique instrument. We also describe our optimisations to use the Blue
Gene/P at very high efficiencies, maximising the effectiveness of the entire
telescope. A thorough performance study identifies the limits of our system.
