Von Neumann architecture
Von Neumann architecture marks the beginning modern information system processing. To fully understand why it is so important, we must first consider the purpose of computer programs. We can then fathom the magnitude of this architecture. The von Neumann architecture allows instructions and data to be mixed and stored in the same memory module and the contents of this memory are addressed by location only. This all takes place in a sequential order. The Von Neumann machine had five basic parts comprised of memory, ALU, the program control unit, input equipment & output equipment. The programs uses a language that to the naked eye can in most cases resemble spoken language. Upper-level languages such as C and Java are designed with this in mind. However, computers understand natural language without signiﬁcant human effort. The physical hardware cannot truly understand language, but instead processes electrical signals. Computer programs are a list of and data, and are represented as binary strings. We can produce a list of high level requirements that a Central Processing Unit (CPU) could execute. This then leads us to a list of functional units that implement the high-level functionality. Neumann m/c are called control flow computer because instruction are executed sequentially as controlled by a program counter. To increase the speed, parallel processing of computer have been developed in which serial CPU’s are connected in parallel to solve a problem. Even in parallel computers, the basic building blocks are Neumann processors. The von Neumann architecture is a design model for a stored-program digital computer that uses a processing unit and a single separate storage structure to hold both instructions and data. It is named after mathematician and early computer scientist John von Neumann. Such a computer implements a universal Turing machine, and the common "referential model" of specifying sequential architectures, in contrast with parallel architectures. One shared memory for instructions (program) and data with one data bus and one address bus between processor and memory. Instructions and data have to be fetched in sequential order (known as the Von Neumann Bottleneck), limiting the operation bandwidth. Its design is simpler than that of the Harvard architecture. It is mostly used to interface to external memory.
The CPU has to be able to send various data values, instructions, and information to all the devices and components inside your computer as well as the different peripherals and devices attached. If you look at the bottom of a motherboard you'll see a whole network of lines or electronic pathways that join the different components together. These electronic pathways are nothing more than tiny wires that carry information, data and different signals throughout the computer between the different components. This network of wires or electronic pathways is called the 'Bus'. That's not that difficult to comprehend, but you've probably heard mention of the internal bus, the external bus, expansion bus, data bus, memory bus, PCI bus, ISA bus, address bus, and control bus it really can get quite confusing.
A computer's bus can be divided into two different types, Internal and External. The Internal Bus connects the different components inside the case: The CPU, system memory, and all other components on the motherboard. It's also referred to as the System Bus. The External Bus connects the different external devices, peripherals, expansion slots, I/O ports and drive connections to the rest of the computer. In other words, the External Bus allows various devices to be added to the computer. It allows for the expansion of the computer's capabilities. It is generally slower than the system bus. Another name for the External Bus, is the Expansion Bus. So now we know the bus is just a bunch of tiny wires (traces and electronic pathways). One...
References: Connecting with computer science Greg Anderson, David Ferro, & Robert Hilton
The Computer as Von Neumann Planned It. M.D. Godfrey & D.F. Hendry
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