WYSE Academic Challenge Computer Fundamentals Test (State Finals)

Transcription

1 WYSE Academic Challenge Computer Fundamentals Test (State Finals) What is the decimal value for the result of the addition of the binary values: ? (Assume a 4 bit, 2's complement representation.) a. 4 b. -4 c. 12 d. 100 e What is the decimal value of the hexadecimal number 511 h? a. 329 b. 511 c. 657 d e Given the hexadecimal integer, 12F0 h, when this value is right shifted by 4 bit positions the result is equivalent to which of the following decimal operations? a. zero the value b. multiply by 4 c. multiply by 16 d. divide by 16 e. divide by 4 4. A small computer uses a 12 bit 2's complement representation of signed integers and fixed point numbers. If fixed point values have the lower 6 bits as the fraction, what is the decimal result when the binary values are added? a. 3.0 b c d e

2 5. A computer stores a floating point binary number in a 16 bit word. Such a number has the form: SIGN 0.xxxxx 2 EXPONENT The mantissa is a fraction between 0 and 1 and is stored in the lower 8 bits of the word. The upper 8 bits are used to store the sign of the mantissa (most significant bit) and a 7 bit value for the exponent. The signed exponent value is stored as an excess 64 code representation. The interpretation of a stored value is a b. 2.0 c d e The truth table at the right is for which Boolean function? a. F = ABC + BC b. F = AC + BC c. F = AC + BC + A C d. F = AB + ABC + B e. F = A B + AC + BC 7. A clock signal is used by a microprocessor to coordinate steps in processing by CPU instructions. Multiple layers of logic gates are needed to perform some operations. Each gate requires a finite delay time to produce a valid output from its inputs. If the clock speed is 50 megahertz, and a standard gate delay is 4 nanoseconds, how many layers of gates can be used in the processor design to get a result in one clock cycle? a. 50 b d. 5 e A serial data output transmission protocol is specified as: 1 start bit, 8 data bits, 2

3 stop bits, and even parity. How many bits are sent on the channel for each byte in a file to be sent? a. 8 b. 9 c. 10 d. 11 e An option is offered on some microcomputers of using a caching disk controller which has 16 Mb of RAM as a cache. How does this option improve system performance when the CPU clock rate and bus width are the same whatever disk controller is used? a. It increases the amount of data that can be stored on the disk. b. Most disk accesses are to data in the neighborhood of previously accessed data and memory access is faster than read or write operations. c. both of the above d. It permits a parallel CPU to perform data processing and instruction decoding before sending data to the primary CPU. e. It does not increase system performance. 10. A large corporate computer system manager has growing word processing needs and has to decide whether to buy another mainframe computer and terminals; or instead to buy microcomputers. We will ignore any other costs of data conversion, etc. and just consider performance available to a user at his/her desktop. The mainframe provides 1000 Million Instructions Per Second (MIPS) of which 20 % are consumed by operating system overhead. The mainframe will support 100 simultaneous users on a timesharing network. A Pentium- based microcomputer executes about 2 instructions per clock cycle and its operating system uses up 33% of available instruction cycles. What is the minimum clock speed (in megahertz) for a

4 Pentium microcomputer user to give the same computing performance in MIPS as the average share he/she would get of the mainframe as 1 of 100 users? a. 1 MHZ b. 6 MHZ c. 33 MHZ d. 100 MHZ e. 240 MHZ 11. The use of Read Only Memory (ROM ) a. provides software storage for startup software independent of magnetic disks. b. prevents accidental or malicious changes to software. c. provides a simple way to add new features to system software. d. provides much faster retrieval rates than RAM. e. Two of the above are true.

5 12. You and 5 co-workers on a project need to share project information with database software. The Microsoft Access database software is selected. Each worker has his or her own microcomputer connected to a local area network (LAN). Multiple workers will use the software to read data simultaneously, but only one will be permitted to update the database. Your supervisor purchases one copy which is not specifically designated as a network license. The supervisor delivers it to you, and instructs you to put it on the LAN and share it with your co-workers. a. This is proper use under the fair use doctrine of the Copyright law. b. This is typically allowed by a software license. c. This is a violation of a trade secret. d. This is a patent infringement. e. This is software piracy. 13. Your microcomputer has two fixed, non-removable hard drives (C: and D:, 200 Mb each), a tape cartridge (drive E:), and a floppy disk (drive A:). The backup software permits backup to any of drives A:, C:, D: or E:. You decide that 70 MB of software and data on C: should be backed up. Considering convenience and risks of hardware failure, the best method to use is to a. put backups on floppy disks. b. put backups on a tape cartridge. c. put backups in a different directory on C:. d. put backups on both drive C:, and D:. e. none of the above 14. A displayed image is 600 x 800 pixels on a color monitor. This image can be used for text, in two ways, either in a text mode or in a graphics mode display. In text mode, the screen is represented by 25 lines of 80 ASCII characters, each of which has an attribute byte for color, etc. In the graphical mode (256 color) each pixel is represented by one byte of data. In the graphical mode, fonts are programmable and scalable. The font generation and scaling, of course require more computation. If

6 the processor performance required to display a screen is proportional to the amount of data to define a screen, how much faster does the processor have to be to give the same apparent speed performance in a graphical user interface compared to a text based interface for word processing? a. 10 times faster b. 30 times faster c. 60 times faster d. 120 times faster e. 240 times faster 15. A limitation on future progress in making computing components faster by making them smaller is requiring the development of new fabrication technologies because a. the size of elements in the design are about the size of the wavelength of light. b. manufacturers can t get air and water clean enough. c. the precious metals used are getting too expensive. d. the supply of silicon is being exhausted. e. all of the above 16. A general model of a computer is based on a single processor, with an Arithmetic Logic Unit. This processor decodes and executes binary instructions. Instructions and data are stored in a sequence in memory. The processor retrieves from and writes to a fixed size, random access memory. This fundamental model is referred to as a a. Von Neumann machine. b. massively parallel machine. c. Turing machine. d. microprocessor. e. minicomputer. 17. The technology which is used to interconnect the integrated circuits and other electronic components that make up a desktop computer is/are a. a printed circuit board. 2. a wire wrapped backplane.

7 3. transistors. d. point to point soldered wires. 5. a micro wave conduit. 18. The following statement is a declaration for an array. What is size of the array? integer x[2.. 9, ] a. 4 b. 12 c. 40 d. 126 e An array, A(N), has been sorted into non-descending sequence. The array is searched starting with index 0, in a linear search. The condition IF ( A(N) = 42 ) will find. a. the only value equal to 42 in the array. b. the first value equal to 42 which may be in the array. c. the last value equal to 42 which may be in the array. d. the first value greater than 41 which may be in the array. e. the last value greater than 41 which may be in the array.

8 20. In the following block of pseudocode for a program, the loop termination. WHILE ( N > 0 ) X(N) = A + B N = ADAM(N); END WHILE a. occurs if a value ADAM(N) = 0 is reached b. will occur if a value of ADAM(N) less than zero is reached c. either of the above d. none of the above e. occurs at the first value of N > What is the printed output of the following pseudo-code? J = 1 for I = 1 to 3 while J < (2*I) print (*) J = J + 1 end while end for a. a string of 4 asterisks b. a string of 5 asterisks c. a string of 9 asterisks d. a string of 10 asterisks e. a string of 12 asterisks 22. A computer virus can a. destroy some or all of your files.

9 b. corrupt part of the data in some of your files. c. slow or halt your computer by diverting the use of memory or CPU time. d. fill up your disk with unwanted files. e. do any of the above. 23. An adequate set of test data used to verify the functionality of a software program should a. include all possible data that the program might use.. b. be limited to the maximum and minimum values for each data range. c. be limited to a few data items selected randomly by the programmer. d. execute every possible path element in a graph of the program s control flow. e. be a set of representative correct input values.

10 24. How many integers are printed by the following? integer L, M, N for L = 1 to 4 by 1 for M = L to 5 by 2 print M endfor for N = 4 to 0 by -2 print N endfor endfor a. 20 b. 22 c. 25 d. 35 e. 40 Use the pseudocode below for questions # 26, 27 and 28. The code operates on a sorted array A with N integers. The array is initially in increasing order, with the first element as A[1]. Assume the array is initialized as A = { 1,3,11,20,37, 42, 53, 56, 63, 99, 123} procedure PROCEDURE( v, N ) begin integer N, v, left, right, x, count array A[ 1.. N ] left = 1 count = 0 right = N while ( right >= left ) x = (left + right) / 2 if ( v < A[x] ) right = x - 1 else left = x + 1 end if count = count + 1

11 if v = A[x] return ( x ) end while return ( 0 ) end procedure 25. The description of the PROCEDURE above should be a. INSERT value v, in sorted list A. b. DELETE value v, from sorted list A. c. COUNT occurrences of value v, in sorted list A. d. REVERSE the order of the values in list A. e. LOCATE value v, in the sorted list A. 26. The call PROCEDURE (37, 11) returns the value a. 0 b. 1 c. 5 d. 6 e The value of count, just before a call PROCEDURE (37, 11) returns its value, is a. 1 b. 3 c. 4 d. 5 e. undefined 28. The following procedure P is called 3 times to print the results. What is the sequence of results printed? procedure P( X, N ) integer X, N, P begin if (N < 0) return (P = -1) else if (N = 0) return (P = 1) else if (N > 0) return ( P = X P(X, N - 1) )

12 end print P( 0, 1 ) print P( 1, 2 ) print P( 2, 3 ) a. 0, 1, 2 b. 1, 1, 4 c. 0, 1, 8 d. 1, 1, 8 e. 0, 2, Good programming practice in the design of a software code module is to limit each module to about a page of source code, a. to maximize the execution efficiency of the program. b. to conform to ISC regulations. c. to limit the complexity of each functional unit. d. to make individual code units easier to test. e. Both c and d are correct.