Parallel computing those that use concurrency, are more difficult to write than sequential ones, because concurrency introduces several new classes of potential software bugs, of which race conditions are the most common. Communication and synchronization between the different subtasks are typically some of the greatest obstacles to getting good parallel program performance. A theoretical upper bound on the speed-up of a single program as a result of parallelization is given by Amdahl's law. Traditionally, computer software has been written for serial computation. To solve a problem, an algorithm is constructed and implemented as a serial stream of instructions. These instructions are executed
Serial digital interface application and interoperability. An 8-bit parallel digital interface is defined by ITU-R Rec. 601; this is obsolete (however, many clauses in the various standards accommodate the possibility of an 8-bit interface). In SD and ED applications, the serial data format is defined to 10 bits wide, whereas in HD applications, it is 20 bits wide, divided into two parallel 10-bit datastreams (known as Y and C). The SD datastream is arranged like this: whereas the HD datastreams are arranged like this: For all serial digital interfaces (excluding the obsolete composite encodings), the native color encoding is YCbCr format. The luminance