Digital Design and Computer Architecture

Questions: 1. What is the importance of the Principle of Equivalence of Hardware and Software? 2. What is the stored program architecture of a computer? Describe with an example? Answer: 1. The importance of the principle of equivalence of hardware and software: In computing, Hardware is the component of a system to hold the system software and application software. Hard ware is touchable and come with different capacities. All the physical parts, such as, Mouse, monitor, Hard Disk Drives, graphics cards, such as, sound cards, mother board, Graphic card, chips and so on, all of these are considered as physical objects. Software is a set of machine readable instruction, which helps the processor to take steps to perform specific operations. Computer software consists of computer program libraries and documents associated with them. Software, which is installed within the computer hardware, is intangible (not touchable). There is a classification of computer software, based on its goal, i.e. system software, application software (operating system, utilities and device drivers) and malware (Blanchet and Dupouy, 2013). 2. stored program architecture of a computer and its examples: With collaboration of both of the Alan Turing and John Von Neumann, The concept of stored program is proposed. According to their proposed concept- A program should reside inside the main memory for its execution. Instructions in machine code are fetched one-at-a- time from the main memory, decoded and executed afterwards (Harris and Harris, 2007). This describes an architecture of an electronic computer consists of arithmetic and logical unit, processing unit and processor registers. There was a control unit, which contained an instruction register and a program counter and a memory was also in use to store both of data and instruction, I/O mechanisms and external mass storage (Hennessy, Patterson and Arpaci-Dusseau, 2007). The architecture of Von Neumanns proposed system is much simpler than the Harvard architecture. Harvard architecture is also based on concept of stored program system but has only one dedicated set of data buses and address for writing and reading data on memory. In Harvard architecture, there was another set of data and address buses, for fetching instructions from main memory. A stored program digital computer keeps its data and program instructions inside the RAM. Advancement of program controlled computers gave birth to the stored program computers. Examples of Stored-program computers: IBM SSEC gained the capability to treat the instruction as data. Though it was not fully electronic, it was partially electromechanical. There was also a modification of the ENIAC to run as read-only, primitive stored-program computer. The BINAC could run few of the test programs in Feb, March and April 1949 and it did not gain its completeness till September 1949. Bottleneck of Von Neumann architecture is defined by John Backus. According to him- There was a bottleneck of data traffic. The performance problem due to data traffic can be eliminated to some level by different types of mechanisms, with some implication of cache mechanism between the main memory and CPU and allowing several caches for different access paths. Hence data and information can be accessed by several access paths, which reduce data traffic (Von Neumann, Aspray and Burks, n.d.). There was also a possibility of eliminating the problem, using parallel computing i.e. use of Non-Uniform Memory Access (NUMA). References Blanchet, G. and Dupouy, B. (2013). Computer Architecture. London: Wiley. Harris, D. and Harris, S. (2007). Digital design and computer architecture. Amsterdam: Morgan Kaufmann Publishers. Hennessy, J., Patterson, D. and Arpaci-Dusseau, A. (2007). Computer architecture. Amsterdam: Elsevier/Morgan Kaufmann Publishers. Von Neumann, J., Aspray, W. and Burks, A. (n.d.). Papers of John von Neumann on computing and computer theory.