dependencies - ruby on rails - are there any packages or modules that are not written in pure ruby? -

i new ruby on rails. heard ruby on rails needs java virtual machine run.

i ask basic stuff ruby on rails.

it seems ruby on rails can have native code in source code.

from have researched ruby on rails, code runnable on same platform code written.

so when need run code on different platform, using bundler ( rubygems ), can automatically download right version of package.

is correct??

also, packages, there packages or modules not written in pure ruby??

i not sure if there any. if there is, think package manager cannot automatically download right version , developers need pull out , make changes deploy on other machines.

i wasn't sure how @ package dependencies in package. there way find package dependency??

it not clear question asking perhaps can resolve of confusion.

rails framework, distributed ruby gem package runs part of ruby app on 1 of several available ruby interpreters.

neither ruby nor rails depend on jvm. jruby interpreter allows run ruby code within jvm if choose so.

many ruby gems include native extensions may platform dependent. bundler allows express platform specific dependencies in cases need use different gems supply same interface on different platforms. take @ bundler's platform command way check if current platform satisfies requirements of given gemfile.

for example sqlite3 gem requires native c extensions cannot compiled run on jruby platform. projects support jruby must swap in alternative activerecord-jdbcmysql-adapter gem.