They are just bundled packages with the Apache server, MySQL and PHP. M is the mac variant, L is the Linux variant and W is the windows, so you get MAMP, LAMP and WAMP.
From the recent spate of threads you have created recently regarding this I think you should actually take the time to read some documentation that comes with these packages. Most of them are very good.
No offense, but if you aren't skilled enough to use Google to find out answers to relatively simple questions like these, you're heading into a world of hurt trying to set up and administer Linux servers!
Please, please, sit down and do a lot of reading, or hire someone else (like a hosting company).
some people partition for lamp stacks on linux, for use of different filesystems for mysql and apache. for the most part its not necessary depending how big of a site/traffic. But most sites would put mysql on one server and apache on another.
For my dev box everything is on my mac and works great.
No need to set up different partitions (in MAMP at least, I do not know much about LAMP or WAMP).
But, if you are running more than one site on the server, make SURE that you set up Apache Virtual hosts. Just google search "Virtual hosts MAMP" for details.
For dev work it is easier in the long run just to compile Apache and PHP yourself as then you can set all the options exactly as you want. The Apple PHP and Apache are crippled in certain ways (for instance the Apache Apple provide has had URL rewriting turned off as far as I could tell, spent ages trying to get it to work then compiled my own version and bam it worked straight away).