  Software and Computing (S&C) are essential to all High Energy Physics (HEP)
experiments and many theoretical studies. The size and complexity of S&C are
now commensurate with that of experimental instruments, playing a critical role
in experimental design, data acquisition/instrumental control, reconstruction,
and analysis. Furthermore, S&C often plays a leading role in driving the
precision of theoretical calculations and simulations. Within this central role
in HEP, S&C has been immensely successful over the last decade. This report
looks forward to the next decade and beyond, in the context of the 2021
Particle Physics Community Planning Exercise ("Snowmass") organized by the
Division of Particles and Fields (DPF) of the American Physical Society.
