No matter what the application, you want your system's resources performing at their full potential. FreeBSD's advanced features enable you to do just that.
FreeBSD's distinguished roots derive from the latest BSD software releases from the Computer Systems Research Group at the University of California, Berkeley. The book The Design and Implementation of 4.4BSD Operating System, written by the 4.4BSD system architects, thus describes much of FreeBSD's core functionality in detail.
Drawing on the skills and experience of a diverse and world-wide group of volunteer developers, the FreeBSD Project has worked to extend the feature set of the 4.4BSD operating system in many ways, striving constantly to make each new release of the OS more stable, faster and containing new functionality driven by user requests.
+ -FreeBSD's developers attacked some of the more difficult problems in operating systems design to give you these advanced features:
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+- Bounce buffering gets around a limitation in the PC's ISA - architecture that limits direct-memory access to the first 16 - megabytes. - -
-Result: systems with more than 16 megabytes operate more - efficiently with DMA peripherals on the ISA bus.
- A merged virtual memory and filesystem buffer cache continuously tunes the amount of memory used for programs and the - disk cache.
+ administrator is freed from the task of tuning cache sizes.Result: programs receive both excellent memory + disk cache. As a result, programs receive both excellent memory management and high performance disk access, and the system - administrator is freed from the task of tuning cache sizes.
- Compatibility modules enable programs for other operating systems to run on FreeBSD, including programs for Linux, SCO, - NetBSD, and BSDI. + NetBSD, and BSDI.
-Result: users will not have to recompile programs - already compiled for one of the compatible OS's, and will have - access to a greater selection of off-the-shelf software, like the - Microsoft FrontPage - Server extensions for BSDI or WordPerfect - for SCO.
+- Kernel Queues allow programs to respond more efficiently + to a variety of asynchronous events including file and socket IO, + improving application and system performance.
-- Dynamically loadable kernel modules allows new filesystem - types, networking protocols or binary emulators to be added to the - kernel at runtime without having to generate a new kernel image. +
- Accept Filters allow connection-intensive applications, + such as web servers, to cleanly push part of their functionality into + the operating system kernel, improving performance.
-Result: Much time can be saved and 3rd party vendors can - deliver complete subsystems as kernel modules without having to - distribute source or have lengthy installation procedures.
+- Soft Updates allow improved file system performance + without sacrificing safety and reliability, by intelligently + analyzing, caching and rewriting or reordering disk meta-data + operations.
-- Shared libraries reduce the size of programs, saving disk - space and memory. FreeBSD uses an advanced shared library scheme - which offers many of the advantages of ELF, and the current version - offers ELF compatibility for both Linux and native FreeBSD - programs.
-Support for IPsec and IPv6 allows improved security in + networks, and support for the next-generation Internet Protocol, + IPv6. -Naturally, since FreeBSD is an ongoing effort, you can expect newer - features and higher levels of stability with each release.
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-&footer;``FreeBSD has an outline-structured visual configuration editor - ... you can enter the configuration of every device the OS supports - and can therefore get a successful installation on the first try - almost every time. IBM, Microsoft, and others would do well to - emulate FreeBSD's approach.''
+Work in-progress includes support for fine-grained SMP locking in + kernel, allowing higher performance on multi-processor machines, + support for Scheduler Activations, allowing parallelism in threaded + programs, file system snapshots, fsck-free booting, network + optimizations such as zero-copy sockets and event-driven socket IO, ACPI support, and advanced security features such as Mandatory + Access Control.
----Brett Glass, Infoworld, April 8 - 1996.