Review Topics ecs 15



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ECS 15

PART I: Computers



  • Computer science, areas and professions

  • Binary number, hexadecimal, conversion between different bases, ASCII code and unicode.

  • Digital sound, the process of digitizing sound, compression, MP3, compression, digital pictures

  • CPU, memory, storage, motherboard, input/output devices, interfaces, & other components. Their major functionalities and current status, fetch/execute cycle. RAM, BOOT

  • Operating system, different operating systems, functionalities, process management, memory management, event management, other types of software.

  • Application software, suite, web application, open-source, cloud computing

  • Machine language, assembly language, high-level language (and examples), compiler, interpreter

  • Practical usage

Midterm Vocabulary:

Computer science, program, computer, hardware, software, programmer, operating system, computer engineering, software engineer, systems analyst, system manager, network manager, network manager, artificial intelligence, theory of computation, human-computer interaction, information management, database, computer graphics, computer security, MAC, Windows, Linux, personal computer, binary, bit, byte, digital, analog, input device, storage device, sequential access device, random access device, hard drive, optical drive, kilo, mega, giga, sample rate, fragmentation, defragmenter, CD-ROM, CD-RW, DVD, CPU, bus, main memory, RAM, booting, machine language, cache, backwards compatibility, motherboard, interfaces, ALU, register, Control Unit, assembly language, Moore's Law, pipelining, multi-core, clock speed, graphics card, sound card, USB, system software, application software, utility software, malware, file management, process management, virtual memory, multitasking, suite, component, virus, Trojan horse, spyware, worm, time-slicing, task switching, memory management, event management, device driver, user authentication, UNIX, Mac OS, Palm OS, Windows, DOS, Machine language, High-level language, Compiler, interpreter,


The table below lists on the left four types of problems that can occur on a computer. Please complete the table: in the middle column, briefly explain what could be the cause for the problem, and in the left column list possible solutions for solving the problem.


Problem

Cause

Solution

The computer fails the POST tests



One of the essential devices is either failing or is missing

- Check for any loose connections (keyboard, mouse,…}

- Check that the fans are working

- Swap memory


The computer is thrashing



The computer all used all its RAM resources and starts using the hard drive as alternative memory, slowing down significantly.

- Close all applications you are not using anymore

- Get more memory for the computer



The computer becomes very hot



- Most probably one of the fans is not working anymore

- Detect fans that are not working and replace them

The computer “freezes” (i.e. becomes non responsive)


There are many possible reasons:

- The computer may be thrashing and it looks as if it is frozen

- one application has crashed

- the Window manager is down



Unfortunately, often the only solution is to restart the computer (either by turning it off first or in the worst case by unplugging it, or by pressing continuously on the on-off buttom.



Question samples

(I put them in short-question format as examples, and they can be asked in multiple-choices, T/F, filling the blank format as well. Format examples follow. )


What is a byte?

         Binary numbers are represented as a series of 0s and 1s. Each "digit" of a binary number is called a bit.  A byte is a binary numbers containing 8 bits.



What is sampling?

        Analog signals are continuous in time. Sampling is the process of selecting a discrete set of time points at which the signal is digitized first, and then stored.  Sampling is usually performed by an Analog to Digital Converter (ADC).



What is an integrated circuit (IC)?

       It is an electronic component coming from the large scale integration of millions and even billions of simple electronic components such as logical gates and transistors.



How many electronic components are there on a modern CPU?   

        Millions to billions of components



How many instructions are performed during 1 cycle on the CPU?

        5 instructions: (1) Fetch the command from memory (2) Decode the command (3) Fetch the data from memory (4) Execute and (5) Write the result in memory



What does it mean that a CPU runs at 2 GHz?

        It means that this specific CPU may perform up to 2 billions cycles per second.



What is the difference between memory (RAM) and storage?

        Memory is volatile (i.e. erased when the computer is turned off) and transient, while storage is "permanent"

 Cite three input devices on a computer

       Keyboard, mouse, microphone,...



Among these three devices, which one is less likely to be directly on the mother board: CPU, memory, power supply?

       Power supply, as it is the less standard of the three.



What is the difference between a 32 bit bus and a 64 bit bus?

        A 32 bit bus is a link that can transfer 32 bits at once, in parallel, while a 64 bit bus can transfer 64 bits at once.  Any software (including the Operating System) written for 32 bits can be installed on both a 32 bit computer and a 64 bit computer (though it will be more performant on the latter) while a software written for 64 bits can only be run on a 64 bit computer.



What is Linux?

        Linux is an operating system. It is free and Open Source.



What is the BIOS?

        BIOS stands for "Basic Input Output System". It is the first software that runs when you start your computer. It goes through 3 steps:

        - testing (check if all devices are present and in working order)

        - initializing (starts all devices and reads their ROM for specific instructions)

        - detect Master Boot Record, read instruction and boot the operating system

What is thrashing?

        Thrashing occurs when the programs you are running have filled the memory (RAM) resources on your computer. When this happens, the computer starts using disk space as memory, at the severe cost that the whole system becomes really slow.



After setting a new printer on your computer, you get the error message: "New hardware detected; there is no driver available for this device". What should you do?

        A driver is a small program that helps the operating system connect and use the printer (there is one driver for each device attached to the computer).  In the Operating system indicates it does not have the proper driver for your new printer, you need to install it, either from the installation CD provided with the printer, or online from the manufacturer's site.



What is machine language?

        It is the binary language (0s and 1s) used directly by the computer; no one really understand machine language.



What is the main advantage of a compiled language versus an interpreted language?

        Programs written with a compiled language usually run much faster than if they had been written with an interpreted language



ECS 15 Introduction to Computers

Instructor: Liu
Name:

Student ID #:

Session #:

Midterm Exam:

Duration: 50 Minutes



  1. The exam is closed book. However, you may refer to one sheet of A4 paper (double sided) of your own notes.

  2. Try to solve as many as can.

  3. Show your reasoning clearly. If your reasoning is correct, but the final answer is wrong, you will receive most of the credit.

  4. Write your solution on this paper. If you need extra paper, use plain white paper. Write your name on any extra paper.

  5. There are six problems in total.

Good Luck!


Do not write in this box.

Question

1

2

3

4

5

6

Total

Points
























  1. Fill the blanks (2 points each question).

    1. A ___________ is used to convert digital values to analog sound.

    2. ________ (ASCII/Unicode) covers a larger set of characters.

    3. Starting a computer is called _________.

    4. IC is short for_____________, which is critical to the development of microprocessors.



  1. True or False (2 points each).

    1. There is a strict line between operation system software and application software.

    2. It is usually faster to access data stored in memory than that in hard drive.

    3. MP3 is a lossless compression scheme.

    4. The hexadecimal number 99 is the same as the decimal number 99.

    5. Any 2 GHz computer will always run faster than a 1 GHz computer.

    6. Digital sound can be recorded, but it cannot be edited.




  1. Multiple choices (2 points each).




  1. What is a typical size of the memory in a current desktop?

    1. 1GB

    2. 100MB

    3. 100 GB

    4. 1000Mb



  1. 1GiB is exactly

    1. 1billion bits

    2. 1 billion bytes

    3. bytes

    4. 1 million bits



  1. In a modern computer, the Fetch/Execute Cycle operates

    1. Once per second

    2. thousands of times a second

    3. hundreds of thousands of times a second

    4. hundreds of millions of times a second

4. Name three popular operating systems.

5. (5 points) convert F3 (hexadecimal) to its decimal and binary format. Please write down your steps.

Spoiler ..............



  1. Fill the blanks (2 points each question).

    1. A digital-analog converter (DAC) is used to convert digital values to analog sound.

    2. Unicode covers a larger set of characters.

    3. Starting a computer is called booting.

    4. IC is short for integrated circuit, which is critical to the development of microprocessors.


  1. True or False (2 points each).

  1. There is a strict line between operation system software and application software. F – The software shipped as part of the operating system is often used by application software, making it difficult to isolate one part from another.

  2. It is usually faster to access data stored in memory than that in hard drive. T

  3. MP3 is a lossless compression scheme. F – MP3 is a lossy compression scheme.

  4. The hexadecimal number 99 is the same as the decimal number 99. F – The hexadecimal number 99 has decimal value 16^9 + 9 = 153.

  5. Any 2 GHz computer will always run faster than a 1 GHz computer. F – The speed of a computer depends on many factors, such as the program being run, the instructions used by the program, the size and speed of the memory, and many more. Clock speed is usually only a small part of a computer’s perceived speed.

  6. Digital sound can be recorded, but it cannot be edited. F – Digital sound can be edited.




  1. Multiple choices (2 points each).




  1. What is a typical size of the memory in a current desktop?

  1. 1GB

  2. 100MB

  3. 100 GB

  4. 1000Mb



  1. 1GiB is exactly

  1. 1billion bits

  2. 1 billion bytes

  3. bytes

  4. 1 million bits



  1. In a modern computer, the Fetch/Execute Cycle operates

  1. Once per second

  2. thousands of times a second

  3. hundreds of thousands of times a second

  4. hundreds of millions of times a second


  1. Name three popular operating systems .

Windows, MacOS, Linux, Unix, …

5. (5 points) convert F3 (hexadecimal) to its decimal and binary format. Please write down your steps. (this question is on the hard side.)


F3(Hex)= 15*16 +3 = 243 (decimal)
F =1111

3=0011


F3 (Hex)= 11110011 (binary)
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