Name: Viona Z. A. Kaleb Class: IT-2 2014 ID: 001201400064 Computer Organization And Architecture Assignment 1. Describe in your own words the meaning of the following problems: a. The four main functions of a computer. - Data processing Manipulation of information by the computer system (data come in and get processed, and the results go out immediately). Processing uses the processor or random access memory, otherwise known as RAM. Processing involves the computer's ability to alter data at the command of the programmer's input. - Data storage The process of permanently saving data on the computer. This process involves a hard drive of some kind. After data has been processed, it must subsequently be stored on a hard drive as opposed to simply rendered via the RAM, which is not a form of permanent storage. - Data movement The process of moving data from memory to output devices and from input devices to the memory. (move data between itself and the outside world) - Control Controlling the data processing, data storage, and data movement activities. It manages the computer’s resources and orchestrates the performance of its functional parts in response to instructions received. Page 1 of 7 b. The main structural components of a computer. - CPU (Central Processing Unit) controls the operation of the computer and performs its data processing functions - Main Memory stores data - I/O moves data between the computer and its external environment - System Interconnection some mechanism that provides for communication among CPU, main memory, and I/O c. the main structural components of a processor. - Control Unit Controls the operation of the CPU and hence the computer - Arithmetic and Logic Unit (ALU) Performs the computer’s data processing function - Registers Provide storage internal to the CPU - CPU Interconnection Some mechanism that provides for communication among the control unit, ALU, and registers. 1. Describe in your own words the understanding of the following terms and please provide several examples in illustrating explanation: Page 2 of 7 a. General purpose of computer. Any computer-based device that accepts different applications or built to perform a variety of tasks, including the most frequent computing tasks, in a reasonably efficiently manner. It can store and execute multiple programs in its internal storage. Personal computers such as tablets, smartphones, notebooks and desktops are examples of general purpose computers. b. Special purpose computer. A computer designed from scratch to perform a specific function or built to perform specific tasks, such as automatic teller machines or washing machines, traffic-light control systems, weather-forecasting simulators, oil-exploration systems and traffic-control computers. These computer systems perform a singular function. c. What is a stored program computer? A stored-program computer is one which stores program instructions in electronic memory. (Example : EDSAC, EDVAC, BINAC) 2. Describe in your own words the meaning of the following problems: a. The meaning of interrupts and approaches to deal with multiple interrupts. ,Interrupts is the normal sequencing of the processor, provided to improve processor utilization. The approaches to deal with multiple interrupts: - Disable all interrupts while an interrupt is being processed. Define priorities for interrupts and to allow an interrupt of higher priority to cause a lower-priority interrupt handler to be interrupted. Page 3 of 7 b. The benefit of using a multiple-bus architecture compared to a single-bus architecture? Compared to single-bus architecture, the using of multiple-bus architecture have a great advantage in speed and of course, will affect performance also. Instead of using singlebus architecture, it is more convenient to use multiple-bus architecture. Using multiplebus architecture will make each device to connect to own bus, which means that each device will have its own bus. This way, it will be faster to transfer data of each devices, so the data transfer doesn't have to stuck like in the single-bus architecture where many devices are connected to a single-bus, that will eventually reach the capacity of the bus and thus will make the data "queue". Of course, it will cost more to have multiple bus, but the cost will not match the need of faster speed, compared to the one of that singlebus architecture. 3. The hypothetical machine of Figure 3.4 also has two I/O instructions: 0011 = Load AC from I/O 0111 = Store AC to I/O In these cases, the 12-bit address identifies a particular I/O device. Show the program execution (using the format of Figure 3.5) for the following program: a. Load AC from device 5. b. Add contents of memory location 940. c. Store AC to device 6. Assume that the next value retrieved from device 5 is 3 and that location 940 contains a value of 2. Page 4 of 7 4. Consider a hypothetical microprocessor generating a 16-bit address (for example, assume that the program counter and the address registers are 16 bits wide) and having a 16-bit data bus. a. What is the maximum memory address space that the processor can access directly if it is connected to a “16-bit memory”? b. What is the maximum memory address space that the processor can access directly if it is connected to an “8-bit memory”? c. What architectural features will allow this microprocessor to access a separate “I/O space”? d. If an input and an output instruction can specify an 8-bit I/O port number, how many 8-bit I/O ports can the microprocessor support? How many 16-bit I/O ports? Explain. Answer : a. The Maximum memory address space = 2^16 = 64 Kbytes. b. The Maximum memory address space = 2^16 = 64 Kbytes. Page 5 of 7 Therefore, in (a) and (b), the microprocessor is to access 64K bytes, but the difference thing between them is that the access of 8-bit memory will transfer a 8 bits and the access of 16-bit memory may transfer 8 bits or 16 bits word. c. Separate I/O instructions are needed because during its execution will generate separate its own signals I/O signals. That signals will be different from the memory signals which is generated during the execution for memory instructions. Therefore, one more output pin will be needed to carry I/O signals. d.With an 8-bit I/O port number the microprocessor can support 2^8 = 256 8-bit input ports, and 2^8 = 256 8-bit output ports. With an 8-bit I/O port number the microprocessor can support 2^8 = 256 16-bit input ports, and 2^8 = 256 16-bit output ports. Thus, the size of the I/O port will not change the number of I/O ports since the number of I/O ports depends on the number of bits which is used to represent the I/O port number (equals to 8 bits in both cases). 5. Describe in your own words the meaning of the following problems: a. The differences among sequential access, direct access, and random access? - Sequential access Memory is organized into units of data, called records. Access must be made in a specific linear sequence. - Direct access Individual blocks or records have a unique address based on physical location. Access is accomplished by direct access to reach a general vicinity plus sequential searching, counting, or waiting to reach the final location. - Random access Each addressable location in memory has a unique, physically wired-in addressing mechanism. The time to access a given location is independent of the sequence of prior accesses and is constant. b. The general relationship among access time, memory cost, and capacity? Page 6 of 7 - Faster access time, greater cost per bit - Greater capacity, smaller cost per bit - Greater capacity, slower access time c. How does the principle of locality relate to the use of multiple memory levels? It is possible to organize data across a memory hierarchy such that the percentage of accesses to each successively lower level is substantially less than that of the level above. Because memory references tend to cluster, the data in the higher-level memory need not change very often to satisfy memory access requests. Page 7 of 7
