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主题:【文摘】Torvalds: A Solaris skeptic -- 无双公子

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家园 History of Linux and *BSD

First of all, don't confuse FreeBSD (and other BSD derivatives) with the original Berkeley Software Distribution. FreeBSD and NetBSD were created on top of 4.4BSD and Net/2 around year 1992 and 1993. OpenBSD was a fork of NetBSD 1.1 in 1995.

Linux was first introduced by Linus in August 1991 (I was wrong when I said Linux has been around for 12 years. It's longer.) Linux was actually born early than FreeBSD. I don't know if Linus had access to BSD's source then. The well-known fact is that it was Minix that had great influence on Linux. Linux's programming interface mostly adheres to the SVR4 UNIX semantics, rather than to BSD behavior. Nevertheless, being a UNIX-like operating system, imprint of (original) BSD has found the way into the Linux as time goes by, just like how AT&T's SysV has affect in Linux. But to conclude that Linux kernel is a copycat of FreeBSD is simply absurd.

According to the change logs in Linux kernel source code, the Linux procfs was created by Linus in year 1991. FreeBSD didn't even exist by then. The Linux procfs covers much more than just process information as FreeBSD's does. FreeBSD had to introduce the linprocfs to be compatible with Linux. I don't see how Linux is following FreeBSD in this area.

FreeBSD's manual page says that the first packet filter was created in 1983 at CMU. It was then ported to BSD in 1983. The BPF was implemented in 1990. Linux had its first generation of kernel packet filtering facility, ipfwadm, in 1996. The current implementation iptables is the third generation. It is likely true that the original idea was from FreeBSD given that BSD has had it for so long. But then again, this alone cannot support your claim that Linux is just following FreeBSD. It is well-known that *BSD have borrowed much from Linux just as well Linux has learned from them.

It is said that Linux's networking-administration tools was derived from the 4.3BSD code. And more interestingly, FreeBSD is said to have borrowed those code from Linux in return.

While you had bad experience with Linux packet filtering, I know people who are using Linux for firewalls and routers. Linksys has built a whole slew of firewall and router products based on Linux. A friend of mine works for a company building hardware antivirus firewalls for ISPs. The top end model has throughput of 1 giga bit per second, with 600 thousand concurrent sessions. The operating system is Linux.

Linux might have bad implementation of some features. That does not support your conclusion that the Linux community lacks innovation.

While Linux and FreeBSD (and other BSD derivatives) have a lot of features in par, there is one that Linux has been in lead, support to multiple processors. Linux gained SMP support in June 1996, with release of kernel 2.0. It has been much improved since then. Last year, SGI successfully built a 1024-node Linux SMP system. According to its own manual pages, SMP support in FreeBSD only started appearing in year 1997.

So much being said, the point is that both Linux and FreeBSD has learned from each other. Both has its own strengths and weaknesses. You may dislike Linux. There is just no need of spreading FUD against it.

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