Hexspeak - Notable Magic Numbers

Notable Magic Numbers

For more details on this topic, see Magic number (programming).

Many computer processors, operating systems, and debuggers make use of magic numbers, especially as a magic debug value.

  • 0x0000000FF1CE ("office") is used as the last part of product codes (guid) for Microsoft Office components (visible in registry under HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall registry key).
  • 0x00BAB10C ("oo-ba-block") is used as the magic number for the ZFS uberblock.
  • 0x8BADF00D ("ate bad food") is used by Apple in iOS crash reports, when an application takes too long to launch, terminate, or respond to system events.
  • 0x1BADB002 ("1 bad boot") Multiboot header magic number.
  • 0x1CEB00DA ("ice buddha") was used as the origin for the binary file parser IceBuddha.
  • 0xB16B00B5 ("big boobs") was required by Microsoft's Hyper-V hypervisor to be used by Linux guests as their "guest signature". This offending code was later changed to 0x0DEFACED ("defaced").
  • 0xBAADF00D ("bad food") is used by Microsoft's LocalAlloc(LMEM_FIXED) to indicate uninitialised allocated heap memory when the debug heap is used.
  • 0xBADDCAFE ("bad cafe") is used by Libumem to indicate uninitialized memory area
  • C15C:0D06:F00D ("cisco dog food") used in the IPv6 address of www.cisco.com on World IPv6 Day. "Dog food" refers to Cisco eating its own dog food with IPv6.
  • 0xCAFEBABE ("cafe babe") is used by Mach-O to identify Universal object files, and by the Java programming language to identify Java bytecode class files.
  • 0xCAFED00D ("cafe dude") is used by Java as a magic number for their pack200 compression.
  • 0xCEFAEDFE ("face feed") is used by Apple in iOS as a header for binary files. In little endian this reads FACEFEED, "Face Feed".
  • 0xD15EA5E ("disease") is a flag that indicates regular boot on the Nintendo GameCube and Wii consoles.
  • 0xDABBAD00 ("dabba doo") is the name of a blog on computer security.
  • 0xDEADBABE ("Dead Babe") is used by IBM Jikes RVM as a sanity check of the stack of the primary thread
  • 0xDEADBEEF ("dead beef") is frequently used to indicate a software crash or deadlock in embedded systems. DEADBEEF was originally used to mark newly allocated areas of memory that had not yet been initialized -- when scanning a memory dump, it is easy to see the DEADBEEF. It is used by IBM RS/6000 systems, Mac OS on 32-bit PowerPC processors and the Commodore Amiga as a magic debug value. On Sun Microsystems' Solaris, it marks freed kernel memory. On OpenVMS running on Alpha processors, DEAD_BEEF can be seen by pressing CTRL-T. The DEC Alpha SRM console has a background process that traps memory errors, identified by PS as "BeefEater waiting on 0xdeadbeef".
  • 0xDEADC0DE ("dead code") is used as a marker in OpenWrt firmware to signify the beginning of the to-be created jffs2 filesystem at the end of the static firmware.
  • 0xDEADDEAD ("dead dead") is the bug check (STOP) code displayed when invoking a Blue Screen of Death either by telling the kernel via the attached debugger, or by using a special keystroke combination. This is usually seen by driver developers, as it is used to get a memory dump on Windows NT based systems. An alternative to 0xDEADDEAD is the bug check code 0x000000E2, as they are both called MANUALLY_INITIATED_CRASH as seen on the Microsoft Developer Network.
  • 0xDEADD00D ("dead dude") is used by Android in the Dalvik virtual machine to indicate a VM abort.
  • 0xDEADFA11 ("dead fall") is used by Apple in iOS crash reports, when the user force quits an application.
  • 0xDEAD10CC ("dead lock") is used by Apple in iOS crash reports, when application holds on to a system resource while running in the background.
  • 0xDEFEC8ED ("defecated") is the magic number for OpenSolaris core dumps.
  • 0xE011CFD0 is used as magic number for Microsoft Office files. In little endian this reads D0CF11E0, "docfile0".
  • face:b00c ("facebook") used in the IPv6 address of www.v6.facebook.com
  • 0xFACEFEED ("face feed") is used by Alpha servers running Windows NT. The Alpha Hardware Abstraction Layer (HAL) generates this error when it encounters a hardware failure.
  • 0xFEE1DEAD ("feel dead") is used as a magic number in the Linux reboot system call.

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