How many viruses are out there written for the various linux
operationg systems compared to windows

Hello Bluekat,

Based on a on line sources, there are well over a hundred viruses (or
other malicious applications) on Microsoft Windows (or DOS) platforms
for each Linux virus. Some references that document this include:

  http://www.desktoplinux.com/articles/AT3307459975.html
A recent article indicating "less than 100" for Linux and "over 74000"
for Windows. Has a number of other good statistics on the effort to
clean up and reasons Linux users should run anti virus software (but
of course - an interview with an anti virus vendor - evaluate
carefully).

  http://itmanagement.earthweb.com/secu/article.php/3086051
An article describing relative security of Linux and Windows. Lists
"more than 200" for Linux and "65000 to 70000" for Windows (excluding
DOS).

  http://www.symantec.com/avcenter/
A summary of current viruses, total count detected by the anti virus
tools is just under 65000 (today). All the "top threats" are for
Windows.

  http://www.sunspot.net/technology/custom/pluggedin/bal-mac082103,0,7518456.column
An article describing Windows vs. Macintosh security, also indicates
"over 70000" viruses for Windows. Note also that Mac OS X shares a
number of comparable features with Linux (as do other Unix based
systems).

As you can see, there is some variation in the numbers. This may be
due to differences in definitions or how a vendor counts variants of a
threat. For example, there are a handful of "sobig" variants - is that
one virus or several? However, the general trend at this point is
still has far more viruses for Windows than Linux.

For more information try using searches such as
  relative number of viruses windows linux
  compare virus number window linux
  number viruses anti virus software

Please use a clarification request if you need further information or
if this answer is not clear.
  --Maniac

thankyou