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
IPAQ (desktop computer) to the RAM limit of the Intel 815 series chipset, the BIOS in the iPAQ prevents the system from booting if there is more than 512 MB installed, instructing the user to decrease the amount of RAM in the system to no more than 512 MB. The first version came in two different models, "Legacy free" which had no parallel, serial, or PS/2 ports and instead 3 additional USB ports on the back; and the traditional one which included the parallel, serial, and PS/2 ports but only had USB ports on the front. The second version had different styling and