5 ms·

Don't iPhones and iPads also have a UNIX kernel?

• lisivka 10y ago
  It's complicated. Original UNIX by AT&T was newer open-sourced. BSD (Berkley Software Distribution) was opensource distribution of user programs for UNIX (like TCP/IP stack, vi editor, etc.), used by original UNIX, with proportions 20% of AT&T code and 80% of BSD code. So technically, BSD is(0.8) not(0.2) UNIX. FreeBSD is branched from BSD code, so it is(0.8) not(0.2) UNIX too. Apple MacOS X is based on FreeBSD code (and lot of other code), and it certified as UNIX compatible, so MacOS X can be named as UNIX. iOS is based on MacOS X, so iOS is UNIX too.
  • JonathonW 10y ago
    If you want to get technical about it, the Mac kernel itself isn't a traditional UNIX or BSD kernel; XNU (which, conveniently enough, stands for "X is not UNIX") is a hybrid composed of the Mach microkernel, some FreeBSD components, and Apple's own driver model. The system as a whole is able to brand itself as UNIX compliant, though, because it complies with the Single UNIX Specification. That spec is concerned about userspace behavior, not kernel or implementation, and you don't have to include any actual UNIX source code to be able to brand your OS as a "UNIX" according to the spec and trademark guidelines.
    • lisivka 10y ago
      Yep, XNU is Mach microkernel + FreeBSD kernel. Some features of XNU are even ported back to FreeBSD kernel. IMHO, that is enough to draw direct connection from XNU to original UNIX (without ™), unlike Linux kernel.
      • TickleSteve 10y ago
        Mach microkernel + FreeBSD userland.... not kernel. BSD is a 'personality' layer.
  • deaddodo 10y ago
    He asked about the Kernel. The Kernel is XNU / Mach, modified to act like a monolithic/hybrid kernel. The BSD code in Mac OS X is all user space, much of which probably isn't in iOS at all.
    • Udo_Schmitz 10y ago
      Nope. Part of kernel as well: https://en.wikipedia.org/wiki/XNU#BSD https://en.wikipedia.org/wiki/XNU#BSD
      • deleted 10y ago
        [deleted]
  • bitwize 10y ago
    Original Unix by AT&T was open sourced under BSD terms, but long after Linux and macOS came into being.
• coldtea 10y ago
  They do, and a certified one at that. Android phone's doesn't, as Linux is not technically a UNIX (doesn't derive from the original UNIX codebase in any way.
  • kgwgk 10y ago
    I don't think iOS is a certified UNIX, is it?
    • coldtea 10y ago
      Can't say for certain, but I think it is. I don't think iOS is anything else than OS X with a different facade (Cocoa Touch, which for UNIX doesn't matter) and a few additional services. It has all the usual POSIX interfaces (and some of the userland) underneath. So even if it violates some models (e.g. with regards to user accounts), it's still the same codebase, heralding from the BSD years.
    • ksherlock 10y ago
      It's not. Apple's only certified for "macOS version 10.12 Sierra on Intel-based Mac computers" (previously that was "Mac OS X Version 10.5 Leopard on Intel-based Macintosh computers", etc) http://www.opengroup.org/openbrand/register/apple.htm http://www.opengroup.org/openbrand/register/apple.htm