Purchasing a Computer in 2016

Part 1 - Purchasing A Computer (the basics)

  1. A bit (b) is the smallest unit of storage on a digital device.
  2. A bit = {0, 1}
  3. A byte (B) is 8 bits and stores a character.
  4. The letter "A" is a character and stores as "01000001".
  5. Conversion Table
    1000 B   = 1 KB (kilo)
    1000 KB = 1 MB (mega)
    1000 MB = 1 GB (giga)
    1000 GB = 1 TB (tera)
    1000 TB = 1 PB (pico)
  6. Most numbers used with computers come from doubling.  Start with a bit.  It has 2 choices: {0, 1}.  Add another bit with the same 2 choices.  Now, for 2 bits, you have 4 choices!
    If you keep doubling, you end up with numbers like this:
    2, 4, 8, 16, 32, 64, 128, 256, 512, 1024

  7. So, technically, 1024 B = 1 KB (but usually when we are talking, we round this to the nearest 1000).

Do you understand what this means?  Try these questions:
  1. Which has more storage? (use <, > or =)
    - 32 GB   or   32 MB?
    - 320 GB   or   3 TB?
    - 16,000,000 KB    or    16 GB?

  2. How many 5MB songs can a 64GB iPod store?
    How many 2GB movies can a 32GB iPad store?

These questions were about storage.  But what about speed?
  1. Have you heard of "GHz"?  What is GHz?

    First, Hz stands for "hertz" and measures frequency (or cycles).
    Specific to computers, "hertz" measures the number of math questions per second that a computer can answer.  We often call this "cycles per second".

    Chips (also known as "processors") are the brains of the computer and are the parts that answer the math questions (cycles).

    And the "G" stands for "giga".  We reuse the prefixes we learned above!  The most common ones are:
    - MHz = megahertz
    - GHz = gigahertz

    So 2GHz means 2,000,000,000 'math questions' per second!

  2. What does a "math question" look like?
    Do you remember learning about NOT, AND and OR gates?
    These are the computer's math questions!  Those gates are what make modern computers work!
Picture
A byte (B) is made up of 8 bits (b).
The byte "01001101" represents the capital letter "L" in the ASCII table of symbols.

Can you see where "01001101" = "4d"?
(If not, use the chart below.)

Binary is base 2. We use "1(2)" or "0001(2)".
Decimal is base 10. We use "1(10)".
Hexadecimal is base 16. We use "1(16)".

In class, we usually converted between binary and decimal. So: 0100(2) = 4(10)
1101(2) = 13(10)

Here's a quick reference between binary, decimal and hexadecimal:
  • 0000(2) = 0(10) = 0(16)
  • 0001(2) = 1(10) = 1(16)
  • 0010(2) = 2(10) = 2(16)
  • 0011(2) = 3(10) = 3(16)
  • 0100(2) = 4(10) = 4(16)
  • 0101(2) = 5(10) = 5(16)
  • 0110(2) = 6(10) = 6(16)
  • 0111(2) = 7(10) = 7(16)
  • 1000(2) = 8(10) = 8(16)
  • 1001(2) = 9(10) = 9(16)
  • 1010(2) = 10(10) = a(16)
  • 1011(2) = 11(10) = b(16)
  • 1100(2) = 12(10) = c(16)
  • 1101(2) = 13(10) = d(16)
  • 1110(2) = 14(10) = e(16)
  • 1111(2) = 15(10) = f(16)

​Now can you see where:
​ "01001101" = "4d"?

We break "01001101" into "0100 1101".
0100 = 4
1101 = d
Therefore, 01001101 = 4d !

Part 2 - Computers by their Parts

Computers have lots of parts.  But what are the most important?
  • Chip (aka "processor") - the "brains" that answer the math questions
  • RAM (aka "memory") - the short-term memory that only works when there is power
  • Storage (includes HDD and SSD) - the long-term memory where your files are saved
  • Motherboard - conducts signals between all parts.  Usually green plastic with circuits inside.  All parts connect to it.
  • Mouse and Keyboard - common input devices, but there are others! (Can you think of any?)
  • Monitor - common output device, but there are others!  (Can you think of any?)
  • Graphics Cards - have chips dedicated to just graphical output.  Gamers, video editors want quality graphics cards!

Chips are measured by speed using hertz.  Common values are in MHz or GHz.
RAM and storage are measured by size using bytes.  Common values are MB, GB, TB.
Monitors are measured using screen size, refresh rates, pixel density and the type of technology used. (Complex!)
  ---  The flyers below have not been updated since 2013.  Might be time!!!  ---
​

Part 3 - Comparing Computers by their Parts

Download the Excel file below.  ("Computer Comparison Chart.xls")
Open this file in either MS Excel or LibreOffice Calc.
Row #1 = The first computer ad in Flyer #1
Row #2 = The third computer ad in Flyer #1
Row #3 = Any online computer ad that you can find.  Try these? -->
Row #4 = Any paper computer ad from a flyer that was brought in.

MS Excel File (to start the chart)

Computer Comparison Chart.xls
File Size: 15 kb
File Type: xls
Download File

Links to Online Ads

UNB Store Flyer #1 or #2
TigerDirect.ca
Dell.ca (click for "Home" deals) or Dell's DFSDirect.ca
HP laptops or desktops
(Staples & Futureshop flyers are available in class.)


The above MS Excel file looks like this:

Brand
& Make
& Model		 Processor
/ Chip
(Intel, AMD)		 RAM
(DDR3)		 Data Storage
(HDD, SSD)		 DVD Network Display Other Price
1.                 
2.                 
3.                 

PAC Part 3 - Comparison Scenarios

Picture
  1. Make a new page on your Weebly site and call it "Comparisons".
    (To make it fancy, drag the page name box slightly left to indent it under the "Purchasing" page.)
  2. Add "Paragraph with Picture" so you can an image of your computer flyer and a link to it.
  3. Add a "Paragraph with Title" to explain about your Excel "Computer Comparison Chart".
  4. Add a "File" (under "Multimedia" side-tab) and upload your Excel file.
  5. Add your Computer Recommendations based on the "Comparison Scenarios".



  



PAC Part 4 - Project: "A Computer for Helen"

Picture
Our end-of-unit project (15 points) is to make a
presentation (MS PowerPoint or LibreOffice) containing a computer recommendation for Helen Parr.

Marking criteria here.


Presentation Bonus

Remember, you can earn a bonus of ~2 points if you do a great presentation using LibreOffice.