Homework on Information in Bits and Bytes (i.e. How does the Computer Store Information in Bits and Bytes)?
8 points total:
2.5 points for Exercise
#1 (0.5 point for each conversion).
2.5 points for Exercise #2 (1.25
point for each conversion).
1 point for #3 for the 5 characters
determined.
1 point
each for #4 and #5 for reporting your findings after the experiments.
1: By using powers of 2 instead of 10 to encode
integers, the computer uses a binary number system to encode an integer in bits
of 0’s and 1’s (instead of 10 different digits in the decimal system).
2: Character are encoded in 8 bits (i.e. 1 byte)
as numbers using the ASCII
character set encoding that maps a character into a number in the range of
0 to 255.
- Exercise
3:
Suppose the 5 bytes (i.e. 5 groups of 8 bits each) of information in Step
1 above (i.e 01000010, 01101001, 01101111,
01101100, and 01100001) are stored as a part of a text file to encode the
information of 5 characters (8 bits for each character) using the ASCII character set
encoding. Explain in your report what the five characters are.
3: Observation: the size of a pure text file
(.txt file) in bytes is close to the number of characters in the file since
each character in a plain text file is encoded in 1 byte of memory.
- Exercise 4: Use NotePad (or other software) to create 4 text files
(files with .txt extension on Windows platform), each of about 100
characters, 200 characters, 400 characters, and 800 characters
respectively and save them as text files. Record and report the sizes of
these files (in terms of bytes). Note that it takes one byte to record a
character. Explain in your report the relationship between the number of
characters and the file sizes you see.
4: Observation: the size of a picture in the
24-bit BMP file format in bytes is about 3 times the number of pixels since the
color of each pixel is encoded in terms of 24 bits, i.e. 3 bytes.
- Exercise
5:
(i)
Press the print screen key on the keyboard to capture the screen as a
picture. Open up Microsoft Paint, paste the image into the canvass, and
save it as a 24-bit bitmap file ( .BMP
file). Check the file size and record it in your report. (ii) On Windows
7 right click on your windows desktop ==> Personalize ==> Screen
Resolution (If it is on Windows XP, instead right
click on your windows desktop ==> property ==> settings) to
get the information regarding the resolution of your screen. What is
your screen resolution X x Y? Record it in your report. For example,
the resolution is 1400 x 1024 for the instructor’s computer in Lib 141.
(iii) Note that if you have a screen resolution of X by Y you have
X*Y pixels on the screen in total, the BMP file uses 24 bits (i.e. 3
bytes) to record the color of each pixel, and it will take X*Y*3 bytes in
the BMP file to store the information of your screenshot. Also note
that 1 MB means 1 million bytes. Record in
your progress report whether X*Y*3 is close to the actual BMP file size.
Notes:
·
KB: About 1 thousand bytes (210=1024
bytes)
·
MB: About 1 million bytes (220=1,048,576 bytes)
·
GB: About 1 billion bytes (230=1,073,741,824 bytes)
·
TB: About 1 tera
bytes (240
bytes)