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Files, folders,
directories, URLs,
and IP addresses
Craig L. Zirbel
Math 592
Spring 2008
5/25/2017
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File Structure
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How to think of where files are
stored, how they are grouped
Either think of it as a tree or a
nested structure
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Macintosh / Windows
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Graphical interface organizes files into
nested folders.
Data
Windows
Videos
Adobe
C drive
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Paths and filenames in
windows
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Each file has a text string that tells
where it is
C:\WINDOWS\DATA\DATAFILE.DAT
Everything before the filename is
called the path
The letters at the end, after the last
period, are called the extension
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Paths and filenames in
windows - 2
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In the original DOS (Disk Operating
System), filenames and directory
names could be no more than 8
letters long, and extensions only 3
letters.
Case was ignored, and all files
were stored with uppercase.
This still persists, to some degree.
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UNIX versus DOS
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Files are grouped into directories, not folders
Directories can contain files or other directories
DOS: C:\WINDOWS\DATA\DATAFILE.DAT
UNIX: /25/zirbel/public_html/592/index.html
UNIX is case sensitive! Index.html differs from index.html
Think of it as a tree:
1
2
jsmith
591
public_html
25
5/25/2017
zirbel
592
Math 592 Spring 2008
index.html
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Accessing your files on
personal.bgsu.edu
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When you have an account on
personal.bgsu.edu, you have
permission to put files, change
files, and view files in a certain
directory.
Mine is /25/zirbel
Let’s use WS_FTP to poke around
a bit …
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My “root” directory
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My public_html directory
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The 592 directory
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The /25 directory
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Change directory using ~zirbel
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This is how to refer to your root
directory even when you don’t
know the complete path to it.
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Cannot change to ~yonglin
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Networking and addresses
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personal.bgsu.edu is the network name of a
computer
Following the syntax for paths and filenames,
edu.bgsu.personal might be more appropriate,
because it would go from general to specific.
personal.bgsu.edu/~zirbel refers to zirbel’s
public_html directory, not zirbel’s root directory.
personal.bgsu.edu/~zirbel/592/index.htm
Case is important in filenames!
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IP (Internet Protocol) addresses
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Computers use numbers instead of words to
identify computers on the network. Each
has its own.
personal.bgsu.edu is 129.1.2.169
Bgunix.bgsu.edu is 129.1.3.10
When connected, my laptop is 129.1.87.20
Webmail.bgsu.edu is 129.1.5.20
Everything at BGSU begins with 129; here
we go from general to specific.
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File transfer protocol
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There are programs that allow you
to transfer files back and forth
between two network computers
ftp on Unix and Windows
WS_FTP and WinSCP have GUI’s
Fetch on the Macintosh
Specify the remote computer and
identify your username, give your
password
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Web browsers
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These programs can bring certain files from a
remote computer to your local computer and
display them. That’s all they (used to) do!
The convention is that only files in a directory
called public_html in your main directory are
accessible to web browsers.
If you just specify a path, like
http://personal.bgsu.edu/~zirbel it will assume
you want the file called index.html or index.htm
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Internet Terminology
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URL Uniform Resource Locator
http: is a scheme name. It requests a
Hypertext Transfer Protocol interaction.
//personal.bgsu.edu is the domain name
ftp: is another scheme, which requests
an FTP interaction with the computer
telnet: requests an interactive terminal
window, like the DOS command prompt
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Operating systems
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UNIX
DOS/Windows
Macintosh
LINUX
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UNIX
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Developed since late 1960’s
Volunteer effort, in part
Many useful utility programs,
including sendmail
Stable, security against hackers
Networked for years!
Many (most?) web servers run
UNIX
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DOS / Windows
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Developed since early 1980’s
Fairly open standard, so other
companies can write software for it
Not much security until recently
Relatively new to networking
Many ways for hackers to break
in, many hackers working on it
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Macintosh
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Developed by Apple since the early
1980’s
Closed standard; only Apple can
write software for it
Reasonably good for small
networks
Too small for hackers to worry
about much
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LINUX
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A version of UNIX that can be
installed on a PC
Virtually free
A strong competitor for Microsoft
Now the basis for Macintosh OS X
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