Compressing Files -Stuffit ?

Question

Recently, I had problems with Mail because I was trying to send large files to a number of people - essentially, I must have exceeded my limits, Mail didn't like it and decided to cut me off for 24 hours or so, and anything I tried to send by Mail would just sit in the Outbox. Anyhow, I seem now to have been readmitted to the world of Mail and all is okay !
However, it's set me thinking about the future if I need to send largish files (eg 3 MB). And compressing them.
I'm thinking of getting Stuffit, which most of us know as an expander, but I believe also does compression. So, I've downloaded the trial version and done a few trial runs. But I'm confused.
The file I have trialed with is a 3MB .pdf of a newsletter that I want to send the rounds. If I run it through Stuffic compressor by using DropStuff it produces a compressed file in whatever format I ask it to (.zip or .sitx) But, if I look at information about this newly created compressed file (apple and i) it tells me that it is still 3MB !
So, is it compressed or not ? If it gets sent is it still sent as a 3MB file? If so, what is the point of compressing, when the original file was 3 MB also? Or is it a smaller 3MB than the real 3MB file?
Some info and help would be gratefully accepted !
Thanks.

Answer 1

Hello Christopher,
As Barbara pointed out, you can create a standard ZIP file by just right-clicking (or "Control"-Clicking with a single-button mouse) and saying Create Archive.
But, to answer your question about the lack of compression:
Regardless of the compression method used, not all files will benefit from compression.
Compression only works by clearing up wasted space, and often by substituting symbols for frequently repeated words or other items that are large or repeated.
As an example, some compression methods might use some single-character symbol to replace a recurring phrase or word in a document. Likewise, it might do the same thing in a program to abbreviate longer strings of commands or text in the file.
Think of it as creating short-hand like a court stenographer to allow a larger file to occupy less space. Then, when it is decompressed, the short-hand is translated back into it's original form.
Additionally, any wasted space is removed and documented in short-hand.
So, if a particular file has a lot of wasted space in it, or is written using a less compact form (in it's native format), then compression will make a significant difference in file size.
However, if the program stores it's files in a format that is already compact and efficient, then you might only save a couple of character spaces (if that much) when you compress it.
As a simple method of proving this, take a large file that will compress down to a smaller form. Once it is compressed, try to compress it again. The program will do this, but you'll notice that the second compression is either not effective or very minimal.
This is because the wasted space was already removed from the file. So, there was no additional improvement to be made.
Also, as noted, there are different methods of compression. So, the type of compression you choose will affect the end size of some file types.
For example, a ZIP file may differ in size from a TAR file, which may differ in size from a SITX file, etc. This is because every format has it's own method of creating short-hand. So, some methods may compress certain file types more.
Hope this helps.