About Berkeley UPC (Unified Parallel C)
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 start-up time, typically with a single thread of execution per processor.

In order to express parallelism, UPC extends ISO C 99 with the following constructs:
- An explicitly parallel execution model
- A shared address space
- Synchronization primitives and a memory consistency model
- Memory management primitives
- Many more features

What’s New in this Version
- OSX 10.5 binaries now available
- Multiconf build manager is now enabled by default, providing easy access to multiple UPCR configs (eg debug and opt) from the upcc command line
- lapi-conduit now uses RDMA support on LAPI/Federation systems, when available, to improve communication performance
- Data movement collectives now use a scalable, high-performance implementation
- Add upcc -extern-main flag for programs with main() in non-UPC code
- Suppress harmless warnings caused by a gcc 4.2 optimizer bug
- Document workarounds for a gcc 4.x optimizer bug that can affect the correctness of shared-local accesses in rare cases.
- Upgrade portals network support to be fully native
- Add pthreads support on compute-node Linux
- Value collectives v1.2: minor usability upgrades
- Fully inline local put/get operations for GCCUPC+UPCR
- GCCUPC+UPCR now requires GCCUPC v4.x or newer
- Add native support for OpenIB networks via new ‘ibv’ network
- Many more enhancements.