CS 105P

Week 3: The Central Processing Unit (CPU)

Week 4: I/O

Overview

Word-processing is probably the most useful application we will talk about this semester. Word-processors allow you to,

1. create and modify a plain document with less effort, and
2. create more attractive documents

The CPU is where data is processed. All the other parts of the computer store or move data. The CPU takes in data and "processes" it. What is processing? When you look at the magnificent things produced by a computer you might get the impression that some pretty sophisticated things are going on inside a CPU. Actually, the CPU is doing some pretty mundane arithmetic. It spends most of it's time adding, subtracting and comparing numbers. So, how is it possible that you can get audio and 3-D images from a computer when its most sophisticated component is doing basic arithmetic? Speed, and lots of it. An entry-level CPU operates at about 100 MegaHertz. That is, it has an internal clock running at 100 Million cycles a second. Let's say it takes 10 cycles to complete one of these instructions (like addition, subtraction, or comparison). That works out to 10 million instructions a second!

Objectives

1. Central Processing Unit
• How does a CPU execute an instruction?
• How many bits in a byte, and in a word? (8 bits in a byte. number of bits in a word depends on the architecture of the machine.)
• How many bytes in a kilobyte, a megabyte, a gigabyte? ( Kilobyte = 2^10 bytes or 1024 bytes. Megabyte = 1024*1024 bytes. Gigabyte = 1024*1024*1024)
• Word size. What does it mean that the new Sega Game player is 128 bits?
2. Input/Output devices
• What are the different types of cursor-controlling devices you might find on a laptop computer? (Trackball, miniature joystick, touch pad)
• What are the different types of speech recognition devices? (Speaker dependent, discrete word system, limited vocabulary, limited domain)
• What is the difference between VGA and SVGA? (VGA is an older standard that supports 640x480 pixel resolution. SVGA supports 1024x768.)
• What are some of the uses for CAD/CAM? (Bring products to market faster. Catch design flaws early before prototypes are built. Create specifications that can be directly sent to manufacturing.)
3. Introduction to word processing
• How do you start the word processor?
• How do you create a new document?
• How do you open an existing document?
• How do you select commands from the menu?
• How do you enter text into a word processing document?
• How do you save a word processing document?
• How do you print a word processing document?
• How do you erase a document you have saved to your disk?
4. Word-processing
• What is the insertion point or cursor?
• How do you position the cursor in your document?
• What are some of the ways you can use the features of a word-processor to make a document seem longer? (Increase the size of the margins, Increase the font size, increase the space between lines.)
• How can you see what your document will look like before it is printed out? (File/Print Preview)
• How do you copy and paste?
• How do you find a word in a large document?
• What are the different views of a document?
• How do you change the font, style, and size of text?
• How do you specify a paragraph indent?
• How do you change the alignment of a paragraph?
• How do you specify a bulleted list?
• How do you use the help system to answer a question?

Concepts

1. What is the difference between an internal speaker and sound card? (Almost every computer come with an inexpensive internal speaker. The speaker can handle simple sounds such as single frequency tones. You can use the internal speaker to reproduce more complex sounds using software, but the quality is very poor. Most computers today come with a sound card added as a peripheral or built into the mother board.)
2. Why is computer speech recognition hard? (Speech requires cognitative skills and computers aren't good at cognitive thinking. Computers only follow instructions. We don't fully understand how we perform cognitive tasks so it's hard to program a computer to perform them. Do you think you need cognitive skills to understand speech? Think about the last time you were trying to get the words to a song. Did you first understand random words in the song, or were you more likely to understand phrases. Your knowledge about the subject matter, and allowed you to understand words in a phrase because the words you heard have meaning together. It's very hard to store knowledge and experiences in a computer.)
3. Why is it difficult for a computer to recognize handwritten characters? (Variations in writing styles. Takes lots of computing power, but the devices most likely to benefit from the technology are handheld computers, which need to be small.)
4. What does the control unit (CU) do?
5. What does the arithmetic logic unit (ALU) do?
6. Why divide the CPU into a CU and ALU?
7. What is a register?
8. What is an address?
9. What is a word?
10. Why can't a computer use the decimal system like the rest of us normal people?
11. Why are ASCII codes important?
12. What is EBCDIC?
13. If the computer stores only 0's and 1's how can display and process text, images, and sounds?
14. What are the parallels between the ASCII coding scheme and Internet protocols?
15. What is RAM? Give an example.
16. What is ROM? Give an example.
17. What is a SIMM?
18. What is a computer bus?
19. What is cache memory?
20. What is the motherboard?
21. How is data represented in a computer? (Binary representation. Electrical current on or electrical current off.)
22. How are MIPS related to the MHz clock speeds we have been talking about?
23. Is a computer with 2 Pentium processors twice as fast as a computer with one?
24. Why are the key arranged on the keyboard the way they are?

Word Processing

1. How is formatting different from editing? (Formatting is usually associated with changing the style of a document. Editing is usually changing the contents of a document.)
2. What is word wrap? Why is word wrap useful?
3. What are margins? (Blank space aroud the sides of your document.)
4. What are hidden codes?
5. Why might you want to use a paragraph format to center a title rather than leading spaces to center the title? (If the title or margins change it will still be centered.)
6. What is a font or Typeface?
7. Where do fonts come from? (Fonts are a part of the operating system. That is, if 10 fonts come with your operating system, you will have 10 fonts in your word-processing, graphics, spreadsheet, etc program.)
8. Describe the two classes of fonts: serif and sans serif.(A serif is a small line used to finish off the stroke of a letter. For example, the letter M when displayed with Times Roman font has a serif at each corner. 'sans' means without.)
9. What is character size? (You can control the size of each character.)
10. What is character style? (Bold, italic, underline, strikethrough)
11. What is character weight? (Bold vs normal)
12. What are proportional fonts? (Each character takes up the amount of space that is needed. For example, 'i' takes up less horizontal space than 'M'.)
13. What are non-proportional or monospaced fonts? (Fonts with characters that are the same width.)
14. What is justification? (Paragraph format that spaces characters in each line so that each line fits neatly within the margins.)
15. What is the difference between footnotes and footers? (Footnotes appear once. Footers appear at the bottom of each page.)
16. What might you want to put in a footer? (Page number, date, author, company name, security reference such as confidential, etc)
17. How is character size measured? (By "points". Each point is about 1/72 inch. So a 36 point font has characters about 1/2 inch tall.)
18. What is clip art? (Images you can purchase and insert in your documents.)
19. What is a paragraph format command? (Many commands apply to a paragraph. A paragraph is a group of words with a hard return at the end. A hard return is inserted whey you press the return or enter key. These commands most logically apply to paragraphs. For example, you probably wouldn't want to single space some lines in a paragraph, but double space others.)