Changes between Version 29 and Version 30 of FAQ


Ignore:
Timestamp:
2016-01-08T14:17:23Z (9 years ago)
Author:
Martin Decky
Comment:

how to contribute

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  • FAQ

    v29 v30  
    4242HelenOS source code is managed with [http://bazaar.canonical.com/en/ Bazaar VCS]. We have a central repository which is considered as the most current code base. Several developers also have their private development branches which are publicly viewable.
    4343
     44=== I would like to contribute to HelenOS. Where should I start? ===
     45
     46We have several pages on our wiki that should help and guide any prospective contributors. Please read carefully our general [wiki:HowToContribute summary for contributors] and our [wiki:StudentTips tips for (not only) students] (the tips really do not target only students) and the links on these pages. A natural first prerequisite for any contribution is that you are able to [wiki:UsersGuide/CompilingFromSource compile HelenOS from sources and run it]. But note that compiling HelenOS from sources is not necessary for just casually giving it a try (you can easily [wiki:UsersGuide/QuickStart run a pre-built, supported HelenOS image]).
     47
     48If you want to contribute by reporting a bug to us, please [wiki:HowToFileABug read our instructions on how to file a bug]. Also please consider finishing this FAQ, because it might explain the big picture of HelenOS.
     49
    4450=== How is HelenOS different from UNIX? ===
    4551
    … …  
    4854=== How is HelenOS different from GNU Hurd? ===
    4955
    50 [http://hurd.gnu.org GNU Hurd] reimplements UNIX in a multiserver environment on top of the Mach microkernel. As of version 0.7, the Hurd runs on single-processor ia32 systems. Porting effort to amd64 is underway. Some of the Hurd's components, such as parts of the ```etx2fs``` file server and the ```pfinet``` networking server are in fact scavenged from ancient versions of Linux, while some other components are original. The networking stack has a single-process architecture. NIC and disk drivers are also taken from Linux, but run as part of Mach in kernel mode. There are experimental versions of the Hurd with support for running Linux 2.6.x networking and disk drivers in user mode via the DDE compatibility layer. The Hurd's hardware support is rather limited. As of version 0.7, it did not support USB or sound. The Hurd is a multiuser system and a huge emphasis is put on structuring it in such a way that unprivileged users can work with the computer without needing to acquire the administrator's privileges for certain tasks (e.g. making untrusted/experimental file systems accessible in the file system namespace). The Hurd offers great flexibility in the dynamic configuration of the system through the translator mechanism. Users can modify behavior for a file system path by interposing their own functionality (i.e. setting a translator) that gets activated on open. There are two GNU Hurd distributions: Debian GNU/Hurd and Arch Hurd. The former includes about 80% of the Debian packages, which is still in the very much respectable order of tens of thousands of packages.
     56[http://hurd.gnu.org GNU Hurd] reimplements UNIX in a multiserver environment on top of the Mach microkernel. As of version 0.7, the Hurd runs on single-processor ia32 systems. Porting effort to amd64 is underway. Some of the Hurd's components, such as parts of the ```ext2fs``` file server and the ```pfinet``` networking server are in fact scavenged from ancient versions of Linux, while some other components are original. The networking stack has a single-process architecture. NIC and disk drivers are also taken from Linux, but run as part of Mach in kernel mode. There are experimental versions of the Hurd with support for running Linux 2.6.x networking and disk drivers in user mode via the DDE compatibility layer. The Hurd's hardware support is rather limited. As of version 0.7, it did not support USB or sound. The Hurd is a multiuser system and a huge emphasis is put on structuring it in such a way that unprivileged users can work with the computer without needing to acquire the administrator's privileges for certain tasks (e.g. making untrusted/experimental file systems accessible in the file system namespace). The Hurd offers great flexibility in the dynamic configuration of the system through the translator mechanism. Users can modify behavior for a file system path by interposing their own functionality (i.e. setting a translator) that gets activated on open. There are two GNU Hurd distributions: Debian GNU/Hurd and Arch Hurd. The former includes about 80% of the Debian packages, which is still in the very much respectable order of tens of thousands of packages.
    5157
    5258HelenOS, on the other hand, is a multiserver environment which does not reimplement any legacy system. It has its own microkernel called SPARTAN. Besides ia32, it also supports amd64, arm32, ia64, mips32, ppc32, sparc32 and sparc64 to varying degrees, some of them in multiprocessor configurations. An overwhelming majority of HelenOS components such as file systems, networking stack, device drivers and GUI have been written specifically for HelenOS, so there is virtually no bloat introduced by various compatibility and glue layers, neither there is any additional maintenance burden associated with maintaining aging third-party components. The networking stack is decomposed into several processes, each implementing part of the stack such as IP, TCP or UDP. Essentially all HelenOS drivers run in user mode, the exception being kernel drivers used for debugging purposes and the timer and interrupt controller drivers. HelenOS supports both USB and sound (Sound Blaster 16 and Intel HDA). HelenOS is a single user operating system, even though there has been some experimental work done on multiuser support. HelenOS does not have a direct analogy to the translator mechanism, but the system configuration can be dynamically changed by spawning/killing user space servers that implement certain IPC protocols and by stacking services on top of each other. HelenOS currently does not support very many user applications as the development focus is on subsystems, frameworks and drivers. A very limited support exists for running a few standard development tools inside HelenOS (e.g. binutils, gcc, python and some others). See also the following question.