Admin/PLATFORMS
author wenzelm
Mon Oct 24 20:57:58 2016 +0200 (2016-10-24)
changeset 64387 2a4672722aaa
parent 64344 c1695143de35
child 64402 4f0acbd97491
permissions -rw-r--r--
version provided by web server;
     1 Multi-platform support of Isabelle
     2 ==================================
     3 
     4 Preamble
     5 --------
     6 
     7 The general programming model is that of a stylized ML + Scala + POSIX
     8 environment, with as little system-specific code in user-space tools
     9 as possible.
    10 
    11 The basic Isabelle system infrastructure provides some facilities to
    12 make this work, e.g. see the ML and Scala modules File and Path, or
    13 functions like Isabelle_System.bash.  The settings environment also
    14 provides some means for portability, e.g. the bash function
    15 "platform_path" to keep the impression that Windows/Cygwin adheres to
    16 Isabelle/POSIX standards, although Poly/ML and the JVM are native on
    17 Windows.
    18 
    19 When producing add-on tools, it is important to stay within this clean
    20 room of Isabelle, and refrain from overly ambitious system hacking.
    21 The existing Isabelle bash scripts follow a peculiar style that
    22 reflects long years of experience in getting system plumbing right.
    23 
    24 
    25 Supported platforms
    26 -------------------
    27 
    28 The following hardware and operating system platforms are officially
    29 supported by the Isabelle distribution (and bundled tools), with the
    30 following base-line versions (which have been selected to be neither
    31 too old nor too new):
    32 
    33   x86-linux         Ubuntu 12.04 LTS
    34   x86_64-linux      Ubuntu 12.04 LTS
    35 
    36   x86_64-darwin     Mac OS X 10.8 Mountain Lion (macbroy30)
    37                     Mac OS X 10.9 Mavericks (macbroy2)
    38                     Mac OS X 10.10 Yosemite (macbroy31)
    39                     Mac OS X 10.11 El Capitan (??)
    40                     macOS 10.12 Sierra (???)
    41 
    42   x86-windows       Windows 7
    43   x86_64-windows    Windows 7
    44   x86-cygwin        Cygwin 2.6 http://isabelle.in.tum.de/cygwin_2016-1 (x86/release)
    45 
    46 All of the above platforms are 100% supported by Isabelle -- end-users
    47 should not have to care about the differences (at least in theory).
    48 
    49 Fringe platforms like BSD or Solaris are not supported.
    50 
    51 
    52 32 bit vs. 64 bit platforms
    53 ---------------------------
    54 
    55 Most users have 64 bit hardware and are running a 64 bit operating
    56 system by default.  For Linux this usually means missing 32 bit shared
    57 libraries, so native x86_64-linux needs to be used by default, despite
    58 its doubled space requirements for Poly/ML heaps.  For Mac OS X, the
    59 x86-darwin personality usually works seamlessly for C/C++ programs,
    60 but the Java platform is only available for x86_64-darwin.
    61 
    62 Add-on executables are expected to work without manual user
    63 configuration.  Each component settings script needs to determine the
    64 platform details appropriately.
    65 
    66 The Isabelle settings environment provides the following variables to
    67 help configuring platform-dependent tools:
    68 
    69   ISABELLE_PLATFORM64  (potentially empty)
    70   ISABELLE_PLATFORM32
    71   ISABELLE_PLATFORM
    72 
    73 The ISABELLE_PLATFORM setting variable refers to the 32 bit version of
    74 the platform, even on 64 bit hardware.  Using regular bash notation,
    75 tools may express their preference for 64 bit with a fall-back for 32
    76 bit as follows:
    77 
    78   "${ISABELLE_PLATFORM64:-$ISABELLE_PLATFORM32}"
    79 
    80 Moreover note that ML and JVM usually have a different idea of the
    81 platform, depending on the respective binaries that are actually run.
    82 Poly/ML 5.6.x performs best in 32 bit mode, even for large
    83 applications, thanks to its sophisticated heap management.  The JVM
    84 usually works better in 64 bit mode, which allows its heap to grow
    85 beyond 2 GB.
    86 
    87 The traditional "uname" Unix tool only tells about its own executable
    88 format, not the underlying platform!
    89 
    90 
    91 Dependable system tools
    92 -----------------------
    93 
    94 The following portable system tools can be taken for granted:
    95 
    96 * Scala on top of Java 8.  Isabelle/Scala irons out many oddities and
    97   portability issues of the Java platform.
    98 
    99 * GNU bash as uniform shell on all platforms.  The POSIX "standard"
   100   shell /bin/sh does *not* work -- there are too many non-standard
   101   implementations of it.
   102 
   103 * Perl as largely portable system programming language, with its
   104   fairly robust support for processes, signals, sockets etc.
   105 
   106 
   107 Known problems
   108 --------------
   109 
   110 * Mac OS X: If MacPorts is installed there is some danger that
   111   accidental references to its shared libraries are created
   112   (e.g. libgmp).  Use otool -L to check if compiled binaries also work
   113   without MacPorts.
   114 
   115 * Mac OS X: If MacPorts is installed and its version of Perl takes
   116   precedence over /usr/bin/perl in the PATH, then the end-user needs
   117   to take care of installing extra modules, e.g. for HTTP support.
   118   Such add-ons are usually included in Apple's /usr/bin/perl by
   119   default.
   120 
   121 * The Java runtime has its own idea about the underlying platform,
   122   which affects Java native libraries in particular.  In
   123   Isabelle/Scala the function isabelle.Platform.jvm_platform
   124   identifies the JVM platform.  Since a particular Java version is
   125   always bundled with Isabelle, the resulting settings also provide
   126   some clues about its platform, without running it.
   127 
   128 * Common Unix tools like /bin/sh, /bin/kill, sed, ulimit are
   129   notoriously non-portable an should be avoided.