Connecting with Computer Science Chapter 3 Review:

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1 Connecting with Computer Science Chapter 3 Review: Chapter Summary: Understanding the inner networkings of a computer is important if you are planning a career in computers. The CPU is the real computer in a computer system. Transistors are the smallest hardware unit in a computer and are used to represent 1 s and 0 s in a computer. Transistors are arranged into circuits that provide basic Boolean Logic. The BASIC Boolean operators are: AND OR and NOT. The BASIC Boolean operators can be implemented as digital circuits or gates; simple gates can be combined to form complex circuits that perform specific functions. The main circuits that make up the CPU are: adders, decoders, shifters and flip-flops. Von Neumann architecture, characterized by a fetch-execute cycle and the 3 components of CPU, memory, and I/O devices is the current standard for computers and has been for more than 60 years. Buses transfer information between parts of the Von Neumann architecture. Memory consists of different varieties of ROM and RAM. Mass storage is nonvolatile and used to store large amounts of data semi-permanently. I/O systems consist of input devices, such as: keyboards, mice and output devices such as: monitors and printers. The CPU interfaces with I/O devices via techniques such as polling and interrupt handling.

2 Key Terms: Connecting with Computer Science Chapter 3 Review: Adder (112) AND (106) Arithmetic logic unit (116) BIOS (119) Boolean basic identities (115) Boolean operator (104) Bus (117) Bus protocol (117) Cache memory (120) CD-ROM (122) Control Unit (116) CRT (124) Decoder (112) DRAM (120) DVD (122) Flash drive (122) Flip flop or larch (113) Gate (107) Interrupt handling (126) LCD (124) Motherboard (100) NAND (109) NOT (109) NOR (109) OR (106) PCI (118) Polling (126) Port (123) RAID (122) RAM (119) Refresh rate (124) Register (116) Resolution (124) RGB (124) ROM (119) SATA (119) SCSI (118) Semiconductor (103) Shifter (114) SRAM (114) System bus (117) System clock (117) The circuit in the CPU responsible for adding binary numbers. Boolean operator that returns a true value only if both operands are true. The portion of the CPU responsible for mathematical operations, specifically addition. A ROM (or programmable ROM) chip on the motherboard; the BIOS provides the startup (boot) program for the computer as well as basic interrupt routines for I / O processing. A set of laws that apply to Boolean expressions and define ways in which expression can be simplified; similar to algebraic laws. A word used in Boolean algebra expressions to test two value logically; the main Boolean operators ore: AND OR and NOT. A collection of conductors, connectors and protocols that facilitates communication between the CPU, memory and I /O devices. The set of rules governing the timing and transfer of data on a computer bus High speed memory used to hold frequently accessed instructions and data in a computer to avoid having to retrieve them from slower system DRAM. A 120 mm disc used to store: data, music and video in computer systems by using a laser technology; CDROMS are capable of holding up to 850 MB of information. The part of the CPU that controls the flow of data and instructions into and out of the CPU The technology used in a conventional computer monitor; CRT s use electronic beams to light up phosphor displays on the screen. A digital circuit used in computers to select memory addresses and I /O devices. Dynamic RAM. A generic term for a type of RAM that requires constant refreshing to maintain its information; various types of DRAM are used for the system main memory. A technology that uses lasers and layering technology to store data, music and video on 120 mm discs; DVDs care capable of holding up to 9 GB of information A small thumb-size memory device the functions as though it were a disk drive; Flash drives normally plug into a PC s USB port. A digital circuit that can retain the binary value it was set to after the input is removed; Static RAM is constructed by using flip-flop circuits. A transistor-based circuit in the computer that implements Boolean logic by creating a single output value for a given set of input values. A computer process in which a signal is placed on the BUS to interrupt normal process of instructions and transfer control to a special program designed to deal with events such as I / O requests. (Liquid Crystal Display) A type of electronic device used in a computer monitor; popular in notebook computers and PDA devices and now widely used for desktop monitors. The physical circuit board in a computer that contains the CPU and other basic circuitry and components. A logical AND follows by a logical NOT that returns a false value only if both operands are true. Boolean operator that returns a false value if the operand is true and a true value if the operand is false. A logical OR followed by a logical NOT that returns a true value only if BOTH operands are false. Boolean operator that returns a true value if either operand is true. A system bus used to connect a microprocessor with memory and I / O devices; PCI is widely used in personal computers. A technique in which the CPU periodically interrogates I / O devices to see whether they require attention; Polling requires many more CPU resources than interrupt handling. In the context of I /O devices, the physical connection on the computer that allows an I /O device to be plugged in A collection of connected hard drives arranged for increased access, speed or higher reliability. A generic term for volatile memory in a computer; RAM is fast and can be accessed randomly but requires power to retain its information. The number of times per second that an image is renewed onscreen; A higher refresh rate results in less flickering in the display. A small unit of very high-speed memory located on the CPU; used to store data and instructions for the CPU. A measurement of the granularity of a computer monitor or printer; Usually given as a pair of numbers indicating the number of dots in a horizontal and vertical direction or the number of dots-per-inch. (Red, Green, Blue) A type of computer monitor that displays color as a function of these three colors. A type of memory that retains its information without power; some types of ROM can be programmed. A popular BUS used to connect hard drives and other mass storage devices to the computer. A high speed BUS designed to allow computers to communicate with peripheral hardware, such as disk drives, CD ROMS scanner.. A medium that is neither a good insulator or good conductor of electricity, used to construct transistors. A circuit that converts a fixed number of inputs to outputs that have bits shifted to the left or right, often used with adders to perform multiplication and division. Static RAM. A type of high-speed memory constructed with flip-flop circuits. The main bus used by the CPU to transfer data and instructions to and from memory and I/O devices. A crystal oscillator circuit on a main board that provides timing and synchronization for operating the CPU and other circuitry.

3 Key Terms: (cont) Truth table (105) USB (122) VLSI (115) XOR (110) A table representing the inputs and outputs of a logic circuit; truth tables can represent basic logic circuits as well as complex ones A high-speed interface between a computer and I/O devices; multiple USB devices can be plugged into a computer without having to power off the computer. The current point of evolution in the development of the I.C. VLSI chips typically have more than 100,000 transistors. A logical operator that returns a true value if one, but not both of its operands is true.

4 Connecting with Computer Science Chapter 3 Review: Test yourself: 1.) What is the purpose of a motherboard? The purpose of the main board is to house the CPU [actual computer] as well as the various slot that allows memory and cards that allow peripheral devices to be connected to the motherboard. Allowing the computer to have added functionality. 2.) What does CPU stand for? Central Processing Unit. 3.) What are the 4 basic functions implemented in the CPU? The 4 basic functions implemented in the CPU are: Adding Decoding Storing Shifting 4.) What is the purpose of the decoding circuit? The purpose of the decoding circuit is to react to specific bit patterns by setting an output of 1 when the pattern is recognized. Decoders are often used to select a memory location based on a binary address. 5.) What are the 3 parts of a transistor? The 3 parts of a transistor are: Emitter Collector Base 6.) What are the 3 Boolean operators? The 3 Boolean operators are: AND OR NOT 7.) What type of table is used to represent the inputs and outputs of a logic circuit? Truth table. 8.) What complex circuit is used to address memory? Decoder 9.) What is the output of an XOR gate if both outputs are 0? The output would be ) Which gate is combined with an AND to form the NAND gate? NOT. 11.) What symbol is used for the OR Boolean operator in a Boolean expression?

5 A parallel curved line to the left 12.) Which of the complex digital circuits is used to construct SRAM? SRAM is constructed from flip-flop circuits. 13.) Which memory type is faster: SRAM or DRAM? SRAM is faster than DRAM. 14.) What are the characteristics of Von Neumann architecture? The characteristics of Von Neumann architecture are: Binary instructions are processed sequentially by fetching an instruction from memory and then executing this instruction. Both instruction and data are stored in the main memory system. Instruction execution is carried out by a CPU that contains a CU, an ALU and registers. The CPU has the capability to accept input from and provide output to external devices. 15.) In computer terminology, what is a bus? A bus is: A collection of conductors, connectors and protocols that facilitates communication between the CPU, memory and I/O devices. 16.) What are the 3 signal groups of a bus? Control Access Data 17.) What is the purpose of cache memory? The purpose of cache memory is to hold frequently accessed instructions and data in a computer to avoid having to retrieve them from slower system DRAM. 18.) What is polling Polling is: A technique in which the CPU periodically interrogates I / O devices to see whether they require Attention 19.) Which is more efficient: Polling or Interrupt handling? Interrupt handling. 20.) How is resolution measured? Resolution is measured in: Frames-per-second.

6 Connecting with Computer Science Chapter 3 Review: Practice Exercises 1.) Which of the following is used to create SRAM? Flip-flop 2.) Which of the following is not one of the basic Boolean operators? XOR 3.) Transistors are made up of material. Semiconductor 4.) Which of the following is not one of the bus signal groups? Fetch 5.) Which type of memory cannot be written to easily? ROM 6.) Which of the following memory types is the fastest? SRAM 7.) In a truth table, inputs are represented on which side? Left 8.) Any Boolean expression can be represented by a truth table. True 9.) Inputs of 1 and 0 to an XOR gate produce what output? 0 10.) In a computer, what function does the decoder usually perform? Multiplication 11.) Boolean expressions are simplified though the use of: Algebraic expression 12.) Which type of I/O is most efficient? Interrupt 13.) Which of the following defines the display quality of a monitor? Resolution 14.) Most computers today are based on: Von Neumann architecture

7 15.) What part of the CPU is responsible for the mathematical operations? ALU 16.) A in computer terminology is a set of wires and protocols designed to facilitate data transfer? Bus 17.) Most computers these days use the bus. PCI 18.) The contains instructions and data that provide the startup program for a Computer. BIOS 19.) High speed is used to speed processing in a computer system? Cache memory 20.) The quality of a printer is measured in dpi