What is the difference between various Operating Systems?

what is the use of various O.S;--
DOS
LINUX
Window XP
Window Vista Home and Office

I will buy the Desktop for my home which will be use for studying, Learning and also be used for Stock Exchanges i.e buying and selling of shares.
Please help............

If in doubt go for windows xp , service pack 2.

All O.S hav different file systems nd different kernels,
for basic internet surfin' go for XP
but for programmin' nd geeky stuff LINUX IS D BEST!
my suggestion to u is don't buy VISTA is sucks,as it's just visually apeallin' nd nuthin' else nd it eats ur RAM like anythin'!
so buy a XP den dwld linux ,nd make ur system DUAL BOOT i.e xp nd linux both , i hav d same thin' on my pc

You can go for windows xp bcoz it supports everything as per ur requirements....moreover some softwares don't support Unix or Linux...but 95% of the softwares & games too supports windows xp...

dos - Command based os no GUI
Liniux - Powerfull security & Virush pruff but hard to use.
Window xp - Popular better GUI & sucessfull Os
Windows Vista - Excellent GUI & more plug & plag facility but Required More Hardware resources.

In DOS and LINUX u must know the commands to do work .eventhough u can work with LINUX which is also a user friendly.over it WINDOWS XP is the right choice because if u do ONLINE TRADE MARKETING it will respond u more and also for studying..etc.so buy WINDOWS XP.

Your list is not a list of different OS's . I see only two different OS. One windows & other linux. The evolution of windows is your list DOS->Windows xp -> Windows Vista home and office. If playing (not gaming, but fiddling around with setting, etc) with pc is not your type. I would suggest you go with Windows Xp SP2 with some good anti-virus. if you words learning means learning about computers then i would certainly recommend Linux (esp. Ubuntu).

Hey Buddy
both windows-xp ,Vista & linux is good.but both have it's own advantages. Just like linux gives good security futures but.. it's the main problem is few compatible softwares & hardwares come for Linux.

But, windows u'll get a lot of supporting softwares & hardwares rather than Linux & Vista is windows next OS. It's really coolest one. but ..... it required some specific hi-fi system configuration for using it's full futures.

I think if u've the enough configuration for using Vista then u should go for Vista as it is new,latest & coolest from any other version of window's else no doubt Windows-XP SP-2 is all time fev. of many users & professionals.