Arstechnica asks "How much power will homebrew users have access to on the PS3?" "But how much of the PS3's architecture will be accessible under Linux? Certainly anything to do with Digital Rights Management (DRM) or playing burned copies of protected games will be locked out. It's also possible that Sony will reserve some of the more advanced graphics and sound features for the big-name PS3 game developers. However, this doesn't mean that Linux on the PS3 will be no different from running it on any generic PC or Macintosh. IBM has made sure of that: "Unlike existing SMP systems or multicore implementations of other processors, on the Cell, only the general purpose PowerPC core is able to run a generic operating system, while the SPUs are specialized to run computational tasks. Porting Linux to run on Cell's PowerPC core is a relatively easy task because of the similarities to existing platforms like IBM pSeries or Apple Power Macintosh, but this does not give access to the enormous computing power of the SPUs. Only the kernel can directly communicate with an SPU and therefore needs to abstract the hardware interface into system calls or device drivers. The most important functions of the user interface include loading a program binary into an SPU, transferring memory between an SPU program and a Linux userspace application, and synchronizing the execution." The IBM port of Linux allows developers to access the Synergistic Processing Units (SPU, sometimes referred to as SPEs in Sony documentation) using their unique instruction set, by creating a virtual file system that can be accessed by userland applications. From a shell prompt, you can even mount the SPU and do a directory listing with ls, with various elements (the small amount of local memory, registers, and the "mailbox" where messages are sent to and from the SPU) appearing as files. These files can then be accessed with standard Unix system calls. This file system is known as "SPUFS" or "Synergistic Processing Unit File System."