Unified Parallel C (UPC) is an extension of the C programming language designed for high performance computing on large-scale parallel machines. The language provides a uniform programming model for both shared and distributed memory hardware. The programmer is presented with a single shared, partitioned address space, where variables may be directly read and written by any processor, but each variable is physically associated with a single processor. UPC uses a Single Program Multiple Data (SPMD) model of computation in which the amount of parallelism is fixed at program startup time, typically with a single thread of execution per processor. Berkeley UPC is an open-source, portable, high-performance implementation of UPC, which includes both a source-to-source translator and a runtime system which is shared by several other UPC compilers. This directory contains a mirror of the download archive for the Berkeley UPC runtime, which includes an embedded copy of the GASNet communication system. The source downloads are officially hosted at: https://upc.lbl.gov For more information, see the README, INSTALL.TXT and ChangeLog files embedded in each archive, or contact upc-users@lbl.gov.