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diff --git a/docs/1 - Introduction.txt b/docs/1 - Introduction.txt new file mode 100644 index 0000000..085b034 --- /dev/null +++ b/docs/1 - Introduction.txt @@ -0,0 +1,108 @@ +File.........: 1 - Introduction.txt +Copyrigth....: (C) 2010 Yann E. MORIN <yann.morin.1998@anciens.enib.fr> +License......: Creative Commons Attribution Share Alike (CC-by-sa), v2.5 + + +Introduction / +_____________/ + + +crosstool-NG aims at building toolchains. Toolchains are an essential component +in a software development project. It will compile, assemble and link the code +that is being developed. Some pieces of the toolchain will eventually end up +in the resulting binary/ies: static libraries are but an example. + +So, a toolchain is a very sensitive piece of software, as any bug in one of the +components, or a poorly configured component, can lead to execution problems, +ranging from poor performance, to applications ending unexpectedly, to +mis-behaving software (which more than often is hard to detect), to hardware +damage, or even to human risks (which is more than regrettable). + +Toolchains are made of different piece of software, each being quite complex +and requiring specially crafted options to build and work seamlessly. This +is usually not that easy, even in the not-so-trivial case of native toolchains. +The work reaches a higher degree of complexity when it comes to cross- +compilation, where it can become quite a nightmare... + +Some cross-toolchains exist on the internet, and can be used for general +development, but they have a number of limitations: + - they can be general purpose, in that they are configured for the majority: + no optimisation for your specific target, + - they can be prepared for a specific target and thus are not easy to use, + nor optimised for, or even supporting your target, + - they often are using aging components (compiler, C library, etc...) not + supporting special features of your shiny new processor; +On the other side, these toolchain offer some advantages: + - they are ready to use and quite easy to install and setup, + - they are proven if used by a wide community. + +But once you want to get all the juice out of your specific hardware, you will +want to build your own toolchain. This is where crosstool-NG comes into play. + +There are also a number of tools that build toolchains for specific needs, +which are not really scalable. Examples are: + - buildroot (buildroot.uclibc.org) whose main purpose is to build root file + systems, hence the name. But once you have your toolchain with buildroot, + part of it is installed in the root-to-be, so if you want to build a whole + new root, you either have to save the existing one as a template and + restore it later, or restart again from scratch. This is not convenient, + - ptxdist (www.pengutronix.de/software/ptxdist), whose purpose is very + similar to buildroot, + - other projects (openembedded.org for example), which are again used to + build root file systems. + +crosstool-NG is really targeted at building toolchains, and only toolchains. +It is then up to you to use it the way you want. + + +History | +--------+ + +crosstool was first 'conceived' by Dan Kegel, who offered it to the community +as a set of scripts, a repository of patches, and some pre-configured, general +purpose setup files to be used to configure crosstool. This is available at +http://www.kegel.com/crosstool, and the subversion repository is hosted on +google at http://code.google.com/p/crosstool/. + +I once managed to add support for uClibc-based toolchains, but it did not make +into mainline, mostly because I didn't have time to port the patch forward to +the new versions, due in part to the big effort it was taking. + +So I decided to clean up crosstool in the state it was, re-order the things +in place, add appropriate support for what I needed, that is uClibc support +and a menu-driven configuration, named the new implementation crosstool-NG, +(standing for crosstool Next Generation, as many other comunity projects do, +and as a wink at the TV series "Star Trek: The Next Generation" ;-) ) and +made it available to the community, in case it was of interest to any one. + + +Referring to crosstool-NG | +--------------------------+ + +The long name of the project is crosstool-NG: + * no leading uppercase (except as first word in a sentence) + * crosstool and NG separated with a hyphen (dash) + * NG in uppercase + +Crosstool-NG can also be referred to by its short name CT-NG: + * all in uppercase + * CT and NG separated with a hyphen (dash) + +The long name is preferred over the short name, except in mail subjects, where +the short name is a better fit. + +When referring to a specific version of crosstool-NG, append the version number +either as: + * crosstool-NG X.Y.Z + - the long name, a space, and the version string + * crosstool-ng-X.Y.Z + - the long name in lowercase, a hyphen (dash), and the version string + - this is used to name the release tarballs + * crosstool-ng-X.Y.Z+hg_id + - the long name in lowercase, a hyphen, the version string, and the Hg id + (as returned by: ct-ng version) + - this is used to differentiate between releases and snapshots + +The frontend to crosstool-NG is the command ct-ng: + * all in lowercase + * ct and ng separated by a hyphen (dash) |