Há muita discussão sobre esse tópico, mas no que diz respeito à concerned , sim, é UNIX:
Open source UNIX foundation
- POSIX-compliant, Open Brand UNIX 03 Registered Product
- Open source kernel based on FreeBSD and Mach 3.0
- 64-bit OS using LP64 data model
- Support for multiple CPU and GPU cores via Grand Central Dispatch and OpenCL
- Hand-tuned, standards-compliant scalar and vector math libraries
Standards-based networking
- Complete IP-based architecture supporting IPv4, IPv6, and L2TP/IPSec VPN
- Rich zero-configuration discovery and naming via Bonjour and Dynamic DNS
- Interoperable file serving via NFS, AFP, SMB/CIFS, and FTP
- Powerful Apache web services
- Open Directory services built on LDAP and Kerberos for single sign-on
Comprehensive UNIX user environment
- Standards-based graphics built on PDF (Quartz), OpenGL, and H.264 (QuickTime)
- Full-screen terminal with xterm-256color support
- Familiar UNIX/Linux utilities (such as emacs, vim, and bash)
- Free Xcode developer tools based on Clang/LLVM