Admin/PLATFORMS
author wenzelm
Wed Oct 11 20:57:12 2017 +0200 (22 months ago)
changeset 66844 0746d4781674
parent 66732 e566fb4d43d4
child 66908 9b074f01a305
permissions -rw-r--r--
tuned whitespace;
     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 10.9 Mavericks (macbroy2 MacPro4,1)
    37                     Mac OS X 10.10 Yosemite (macbroy31 MacBookPro6,2)
    38                     Mac OS X 10.11 El Capitan (?)
    39                     macOS 10.12 Sierra (macbroy30 MacBookPro6,2)
    40 
    41   x86-windows       Windows 7
    42   x86_64-windows    Windows 7
    43   x86_64-cygwin     Cygwin 2.8 http://isabelle.in.tum.de/cygwin_2017 (x86_64/release)
    44 
    45 All of the above platforms are 100% supported by Isabelle -- end-users
    46 should not have to care about the differences (at least in theory).
    47 
    48 Fringe platforms like BSD or Solaris are not supported.
    49 
    50 
    51 32 bit vs. 64 bit platforms
    52 ---------------------------
    53 
    54 Most users have 64 bit hardware and are running a 64 bit operating
    55 system by default.  For Linux this usually means missing 32 bit shared
    56 libraries, so native x86_64-linux needs to be used by default, despite
    57 its doubled space requirements for Poly/ML heaps.  For Mac OS X, the
    58 x86-darwin personality usually works seamlessly for C/C++ programs,
    59 but the Java platform is always for x86_64-darwin.
    60 
    61 Add-on executables are expected to work without manual user
    62 configuration.  Each component settings script needs to determine the
    63 platform details appropriately.
    64 
    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  (potentially empty)
    71   ISABELLE_PLATFORM
    72 
    73 The ISABELLE_PLATFORM setting variable prefers the 32 bit version of the
    74 platform, if possible. Using regular bash notation, tools may express their
    75 preference for 64 bit with a fall-back for 32 bit as follows:
    76 
    77   "${ISABELLE_PLATFORM64:-$ISABELLE_PLATFORM32}"
    78 
    79 
    80 There is a second set of settings for native Windows (instead of the
    81 POSIX emulation of Cygwin used before):
    82 
    83   ISABELLE_WINDOWS_PLATFORM64
    84   ISABELLE_WINDOWS_PLATFORM32
    85   ISABELLE_WINDOWS_PLATFORM
    86 
    87 It can be used like this:
    88 
    89   "${ISABELLE_WINDOWS_PLATFORM:-$ISABELLE_PLATFORM}"
    90 
    91   "${ISABELLE_WINDOWS_PLATFORM64:-${ISABELLE_WINDOWS_PLATFORM32:-${ISABELLE_PLATFORM64:-$ISABELLE_PLATFORM32}}}"
    92 
    93 
    94 Moreover note that ML and JVM usually have a different idea of the
    95 platform, depending on the respective binaries that are actually run.
    96 Poly/ML 5.6.x performs best in 32 bit mode, even for large
    97 applications, thanks to its sophisticated heap management.  The JVM
    98 usually works better in 64 bit mode, which allows its heap to grow
    99 beyond 2 GB.
   100 
   101 The traditional "uname" Unix tool only tells about its own executable
   102 format, not the underlying platform!
   103 
   104 
   105 Dependable system tools
   106 -----------------------
   107 
   108 The following portable system tools can be taken for granted:
   109 
   110 * Scala on top of Java 8.  Isabelle/Scala irons out many oddities and
   111   portability issues of the Java platform.
   112 
   113 * GNU bash as uniform shell on all platforms.  The POSIX "standard"
   114   shell /bin/sh does *not* work -- there are too many non-standard
   115   implementations of it.
   116 
   117 * Perl as largely portable system programming language, with its
   118   fairly robust support for processes, signals, sockets etc.
   119 
   120 
   121 Known problems
   122 --------------
   123 
   124 * Mac OS X: If MacPorts is installed there is some danger that
   125   accidental references to its shared libraries are created
   126   (e.g. libgmp).  Use otool -L to check if compiled binaries also work
   127   without MacPorts.
   128 
   129 * Mac OS X: If MacPorts is installed and its version of Perl takes
   130   precedence over /usr/bin/perl in the PATH, then the end-user needs
   131   to take care of installing extra modules, e.g. for HTTP support.
   132   Such add-ons are usually included in Apple's /usr/bin/perl by
   133   default.
   134 
   135 * The Java runtime has its own idea about the underlying platform,
   136   which affects Java native libraries in particular.  In
   137   Isabelle/Scala the function isabelle.Platform.jvm_platform
   138   identifies the JVM platform.  Since a particular Java version is
   139   always bundled with Isabelle, the resulting settings also provide
   140   some clues about its platform, without running it.
   141 
   142 * Common Unix tools like /bin/sh, /bin/kill, sed, ulimit are
   143   notoriously non-portable an should be avoided.