1.
The file ``sample.tex''
is the file that contains all the author's work,
i.e., her actual typed words and formulae.
It was typed using the text editor vi.
Similar text editors include emacs,
pico,
Notepad (in Windows), and
TextEdit (on Macs).
Some LaTeX programs provide their own text editor.
2.
Running LaTeX to compile the document produces
the file ``sample.dvi''.
On computer ucsub the typed command was ucsub>   latex sample.tex
The dvi stands for ``device independent''; the
file sample.dvi is the same regardless of
(1) which computer is used to compile the document, or
(2) what kind of printer it is headed for.
In fact, it is too universal to be printed in this form;
it must still be translated to a form suitable for a
specific kind of printer. (Different printers speak
different languages...)
You can't even view the DVI file unless you use a special
``DVI Viewer'', such as xdvi on ucsub.
3.
The files
``sample.aux''
``sample.log''
are two by-products of the compiling command.
The aux file is used if the document contains
more complicated stuff, like bibliography and
cross-references.
The log file contains a full record of the
compilation, including errors you need to correct,
e.g., misspelled macros, missing bracket or parenthesis,
missing references, etc.
4.
The file ``sample.ps'',
a PostScript file, the kind understood by most laser printers.
A printable PostScript file is created from the
dvi file by the translating program dvips.
On computer ucsub the typed command was ucsub>   dvips sample.dvi
5.
The file ``sample.pdf''
is the PDF form of the document.
As of 2003, this is as
web-friendly a document as possible. Using Acrobat Reader,
any computer can be used to view the document and/or print it.
On computer ucsub the command ucsub>   dvipdf sample.dvi
translated the DVI file to PDF form.
However, one gets a crisper PDF document directly
from the LaTeX source file by using the (newer)
program ``pdflatex'': ucsub>   pdflatex sample.tex