Principles of Digital Computing - Research Paper Example

Principles of Digital Computing INTRODUCTION OBJECTIVE The objective of this research is pursuance of history of digital computation technology, its design, impacts and its comparison in terms of advantages and disadvantages with analog computing. HISTORY An insight into the early years of the nineteenth century throws light upon the evolution of digital design theory. Research by various scientists made them believe that computation did not necessarily have to be analog and that digital computation was also possible. The early implementation of digital design was via mechanical and electrical components. Considerable events regarding machine based computations marked the fourteenth and fifteenth centuries with the advent of “Napier’s Bones”, “Pascaline”, “The differential calculus and Mechanical Multiplier”. The 1800s were filled with remarkable achievements. Jacquard’s power loom with an automatic card reader, Babbage’s difference and analytical engines, Ada Augusta’s Programs and subroutines for the analytic engine, George Boole’s Boolean Algebra and Herman Hollerith’s Punch Card Reader and tabulating machine. Charles Babbage Charles Babbage is known as the father of modern computers. He presented a complete digital design to compute and exhibit almost all the features that modern computers have. He introduced logical computations and iterations through digital theory. He proposed designs of two mechanical calculators namely Difference Engine and Analytical Engine. The analytical engine was capable of taking input from punch cards and producing iterations. Ada Augusta Ada Augusta(Lady Lovelace) was an intelligent mathematician. She suggested Charles Babbage with a series of steps that would enable the calculation of Bernoulli numbers. She is accredited as the First-Ever Computer Programmer. As a tribute to her invention a programming language was named Ada after her name in the year 1979. George Boole George Boole is regarded as the father of the field of computer science. He is the inventor of logic gates and thus Boolean logic. These logic gates lay the basis of the modern day digital logic and design. The 1900s saw further advancements in digital technology. Among them the most famous were by: Alan Turing Alan Mathison Turing was a British mathematician. Turing laid the basis of modern computation by conducting the Turing test that intended the creation of a machine that could perform likes humans. John Lewis von Neumann Von Neumann proposed the basic idea of the structure behind present day computers. He proposed the use of a Central Processing Unit for the execution of tasks and the introduction of a separate unit for holding storage. ENIAC 1946 ENIAC – Electronic Numerical Integrator and Computer was the first practical and electronic implementation of Turing principles. It was the first reprogrammable computer that had the ability to execute several programs. METHODOLOGY The Boolean algebra is at core of digital logic or digital circuit design. The efforts Charles Babbage and Lady Ada Augusta proved that the digital computation can be exercised practically with an appropriate hardware. Digital computation sees information in terms of binary digits i.e. 0s and 1s. It comprises of all arithmetic operations, logical operations, iterations through branching, usage of memory and its addressing and subroutines. The digital logic can also be exhibited or implemented through the use of electrical components like electro mechanical relays but, the discovery of semi conductor materials and basic electronic components like diode and switching transistors gave birth to modern digital architecture. Proved to be the most suitable architecture for digital computation the semi conductor component based designs and the implementations revolutionized the digital era. How does it work? The implementation of Boolean algebra is achieved through the logic gates. These are the basic logical and conceptual components physically implemented through the logical arrangement of switching transistors in a circuit. The arrangements of these gates in logical order exhibit all the Boolean computations. For example a half adder shown in Fig 1.1 with the respective truth table 1.1 exhibits the addition of two binary numbers through XOR and AND gates. Figure 1.1 Truth Table 1.1 Input Output A B Cout ∑ 0 0 0 0 0 1 0 1 1 0 0 1 1 1 1 0 The ∑ symbol represents the Least Significant bit and Cout represents the Most Significant bit and carry. The circuit defined above will always perform the same function i.e. addition of two binary digits. For achieving the implementation of other operations different circuits with different components would be needed. This logic can also be implemented through relay based circuits but the problem of acquiring different designs and different components for other computations would remain persistent for that as well. Universal circuits can be achieved through the use of lookup tables. This means that same circuit is capable of exhibiting different functions by just looking up and comparing the inputs provided in the form of a table and producing the respective output recorded already in the table for that set of inputs. This can be done through the use of ROM based circuits and unfortunately the same cannot be exhibited through the electrical or relay based circuits. Figure 1.2 exhibits and example. Figure 1.2 The significance of this approach is marked by the benefits associated. The change in the table input and respective output values would be the change in the functioning of the circuit. These values being software can be changed, stored and copied easily through memory. Large scale implementations of these circuits are well known, such as Arithmetic and Logic Unit (an essential part of computers), Electronic Fuel Injection (EFI) systems and Electronic Thermocouple transmitter. The idea of output routed as input for feedback to these circuits is the basis of another vital device known as Finite State Machine. This enables reading memory addresses sequentially and their contents. The concepts of Allan Turing of a guided programmed computer processor capable of storing, reading, processing and executing instructions thus can be achieved through the high level and very sophisticated implementation of these circuits like MICROPROCESORS. The operation of microprocessors is explained through the fetch (read) and execution cycle. The instruction pointer holds the address of next instruction to be read. Control Unit manages the storage and execution of instructions inside the processor. The instructions to the MU can be given through the combination of binary input which are usually represented in short form through hexadecimal system and referred to as machine language. This language is hard to memorize as different combinations represent different functions. For ease of programming these combinations are further referred through two to four lettered words of English Language called pneumonics. A language that is based on pneumonic is known as assembly language. This language directly has nothing to do with the microprocessor. The opt codes of assembly language need to be translated into machine language that would be comprehendible to the microprocessor. This translation is done by the ASSEMBLER. OPERATING SYSTEMS is software that acts as an interface between the hardware in a digital computer system and the applications’ softwares. It manages the execution of tasks on the user interface level along with allocating specific tasks to the hardware concerned. Operating systems have often been coded in machine language but present times see their implementation in high level programming languages. Present day programming for digital computer is usually not done in assembly language. Instead, high level programming languages are used that are based upon the verbal dialect of humans. Since they are very close to English language humans feel it very easy to deliver their though in them and thus program them. These High Level programming languages are however not understandable to the microprocessor and therefore need a translator that would translate them into a state that the hardware of the system can understand. These translators are of two types. One translator translates step by step execution of a program from its high-level code to the machine language code. It runs the translation step at the execution of every step. Such translators are celled INTERPRETORS. The other type of translators conduct the translation of the entire code into the other language’s code all in one go and create a file of machine language code. This file is then executed all in a go. Such translators are called COMPILERS. (Tony R. Kuphaldt, 2002). PROJECT ANALYSIS The salient features of digital design are attempted to be compared with those of analog design. ADVANTAGES OF DIGITAL TECHNOLOGY  Less expensive, this is because the amount of circuitry required is too less.  More reliable.  Easy to manipulate.  Flexible and single to use. Unlike Analog design clock and phase settings are not required.  Fully compatible with other digital systems.  Digital signals do not get affected with noise in channels with disturbance.  Integrated networks. DISADVANTAGES OF DIGITAL TECHNOLOGY Sampling Error is possible. Requirement of digital output cuscuitry. High bandwidth. Digital data can be transferred over high bandwidth only. Synchronization of communication systems is essential in order to detect digital signal. This is unlike the analogue systems’ structure. ADVANTAGES OF ANALOG TECHNOLOGY Very limited use of Bandwidth Accuracy more as compared to digital circuits. Easy to manipulate mathematically. Compatible with standard VGA boards on a broad installed PC basis Not necessary to purchase a new graphics board. DISADVANTAGES OF ANALOG TECHNOLOGY Clock and phase of the TFTs must be synchronized with the analog signal to avoid pixel jitter, which is a relatively complex issue Cables very less tolerant to external influences specially noise. Signal loss due to noise and distortion impossible to recover. Specific transmitters and receivers required for particular transmission. High cost of signal conversion inside the display. Upgrade to digital interface not possible. CONCLUSION The paper has proposed the differences between the analog and digital design of computation. Starting from the beginning the core design of the digital logic is discussed along with its comparison with the analog logic. Digital logic is dependent on digital architecture for implementation. Attempts to implement this digital logic via mechanical means failed and could not prove to be productive. It was therefore attempted that digital design implemented via digital logic circuits. Analog architecture could not get the support of proper architecture for proper representation of continuous quantities, therefore digital computation prevailed. Their comparison proves that analog computation is more better and accurate than digital computation. REFERENCES: “Principles of digital computing”. http://www.opamp-electronics.com/tutorials/digital_theory_ch_016.htm, 2003. Web. May 26,2011. “Technology World”. http://technologyworld-mobilecommunication.blogspot.com/2009/02/digital-vs-analog-advantages.html, 2009. Web. May 26, 2011. Eiden., H., “Advantages and disadvantages of Digital and Analog Interfaces.”. http://www.tomshardware.com/reviews/tft-guide-part-3,117-2.html, 1999.Web. May 26, 2011. Fig 1.1. Principles of Digital Computing. “A binary adder”; http://www.opamp-electronics.com/tutorials/digital_theory_ch_016.htm,n.d. 2003. Web. 2011. Fig 1.2. Principles of Digital Computing. “Lookup tables”; http://www.opamp-electronics.com/tutorials/digital_theory_ch_016.htm,n.d. 2003. Web. 2011. Read More