FreeBSD Linux Windows 2000
Reliability FreeBSD is extremely robust. There are numerous testimonials of active servers with uptimes measured in years. The new Soft Updates1 file system optimizes disk I/O for high performance, yet still ensures reliability for transaction based applications, such as databases. Linux is well known for its reliability. Servers often stay up for years. However, disk I/O is non-synchronous by default, which is less reliable for transaction based operations, and can produce a corrupted filesystem after a system crash or power failure. But for the average user, Linux is a very dependable OS. All Windows users are familiar with the "Blue Screen of Death". Poor reliability is one of the major drawbacks of Windows. Some of the major issues have been fixed in Windows 2000, but "code bloat" has introduced many more reliability problems. Windows 2000 uses a lot of system resources and it is very difficult to keep the system up for more than a couple of months without it reverting to a crawl as memory gets corrupted and filesystems fragmented. Performance FreeBSD is the system of choice for high performance network applications. FreeBSD will outperform other systems when running on equivalent hardware. The largest and busiest public server on the Internet, at ftp.freesoftware.com, uses FreeBSD to serve more than 1.2TB/day of downloads. FreeBSD is used by Yahoo!, Qwest and many others as their main server OS because of its ability to handle heavy network traffic with high performance and rock solid reliability. Linux performs well for most applications, however the performance is not optimal under heavy network load. The network performance of Linux is 20-30% below the capacity of FreeBSD running on the same hardware 2. The situation has improved somewhat recently and the 2.4 release of the Linux kernel will introduce a new virutual memory system based on the same concepts as the FreeBSD VM system. Since both operating systems are open source, beneficial technologies are shared and for this reason the performance of Linux and FreeBSD is rapidly converging. Windows is adequate for routine desktop apps, but it is unable to handle heavy network loads. A few organizations try to make it work as an Internet server. For instance, barnesandnoble.com uses Windows-NT, as can be verifyed by the error messages that their webserver produces, such as this recent example: Error Message: [Microsoft][ODBC SQL Server Driver][SQL Server]Can't allocate space for object 'queryHistory' in database 'web' because the 'default' segment is full. For their own "Hotmail" Internet servers, Microsoft used FreeBSD for many years. Security
FreeBSD has been the subject of a massive auditing project for several years. All of the critical system components have been checked and rechecked for security-related errors. The entire system is open source so the security of the system can and has been verified by third parties. A default FreeBSD installation has yet to be affected by a single CERT security advisory in 2000.3
FreeBSD also has the notion of kernel security levels. These are much more powerful than simple run-levels since they allow the administrator to completely deny access to certain operating system functions such as reading /dev/mem, changing file system flags, or writing to disks without mounting a filesystem.
FreeBSD includes a very robust packet filtering firewall system and many intrusion detection tools.
The open source nature of Linux allows anyone to inspect the security of the code and make changes, but in reality the Linux codebase is modified too rapidly by inexperienced programmers. There is no formal code review policy and for this reason Linux has been suceptible to nearly every Unix-based CERT advisory of the year. This problem is compounded by the fact that distributions like Red Hat tend to turn on notoriously insecure services by default....