The Kepler General Purpose GPU (GPGPU) architecture was developed to directly support GPU virtualization and make GPGPU cloud computing more broadly applicable by providing general purpose computing capability in the form of on-demand virtual resources. This paper describes a baseline GPGPU cloud system built on Kepler GPUs, for the purpose of exploring hardware potential while improving task performance. This paper elaborates a general scheme which defines the whole cloud system into a cloud layer, a server layer, and a GPGPU layer. This paper also illustrates the hardware features, task features, scheduling mechanism, and execution mechanism of each layer. Thus, this paper provides a better understanding of general-purpose computing on a GPGPU cloud.