Admin/PLATFORMS
author haftmann
Sun Dec 15 15:10:16 2013 +0100 (2013-12-15)
changeset 54745 46e441e61ff5
parent 49144 84699f37481d
child 55391 eae296b5ef33
permissions -rw-r--r--
disambiguation of interpretation prefixes
     1 Some notes on 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 "jvmpath"
    15 to keep the impression that Java on Windows/Cygwin adheres to
    16 Isabelle/POSIX standards, although inside the JVM itself there are
    17 many Windows-specific things.
    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 scripts follow a peculiar style that reflects
    22 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 reference versions (which have been selected to be neither
    31 too old nor too new):
    32 
    33   x86-linux         Ubuntu 10.04 LTS
    34   x86_64-linux      Ubuntu 10.04 LTS
    35 
    36   x86_64-darwin     Mac OS Snow Leopard (macbroy2)
    37                     Mac OS Lion (macbroy6)
    38                     Mac OS Mountain Lion (macbroy30)
    39 
    40   x86-cygwin        Cygwin 1.7 (vmbroy9)
    41 
    42 All of the above platforms are 100% supported by Isabelle -- end-users
    43 should not have to care about the differences (at least in theory).
    44 There are also some additional platforms where Poly/ML might also
    45 happen to work, but they are *not* covered by the official Isabelle
    46 distribution:
    47 
    48   ppc-darwin
    49   x86-darwin
    50   sparc-solaris
    51   x86-solaris
    52   x86-bsd
    53 
    54 There are increasing problems to make contributing components of
    55 Isabelle work on such fringe platforms.  Note that x86-bsd is silently
    56 treated like x86-linux -- this works if certain Linux compatibility
    57 packages are installed on BSD.  Old 32 bit Macintosh hardware is no
    58 longer supported due the its lack of Java 7.
    59 
    60 
    61 32 bit vs. 64 bit platforms
    62 ---------------------------
    63 
    64 Most users have 64 bit hardware and are running a 64 bit operating
    65 system by default.  For Linux this often means missing 32 bit shared
    66 libraries, so native x86_64-linux needs to be used by default, despite
    67 its doubled space requirements for Poly/ML heaps.  For Mac OS X, the
    68 x86-darwin personality usually works seamlessly for C/C++ programs,
    69 but the Java 7 platform is only available for x86_64-darwin.
    70 
    71 Add-on executables are expected to work without manual user
    72 configuration.  Each component settings script needs to determine the
    73 platform details appropriately.
    74 
    75 The Isabelle settings environment provides the following variables to
    76 help configuring platform-dependent tools:
    77 
    78   ISABELLE_PLATFORM64  (potentially empty)
    79   ISABELLE_PLATFORM32
    80   ISABELLE_PLATFORM
    81 
    82 The ISABELLE_PLATFORM setting variable refers to the 32 bit version of
    83 the platform, even on 64 bit hardware.  Using regular bash notation,
    84 tools may express their preference for 64 bit with a fall-back for 32
    85 bit as follows:
    86 
    87   "${ISABELLE_PLATFORM64:-$ISABELLE_PLATFORM32}"
    88 
    89 Moreover note that ML and JVM usually have a different idea of the
    90 platform, depending on the respective binaries that are actually run.
    91 Poly/ML 5.5.x performs best in 32 bit mode, even for large
    92 applications, thanks to its sophisticated heap management.  The JVM
    93 usually works better in 64 bit mode, which allows its heap to grow
    94 beyond 2 GB.
    95 
    96 The traditional "uname" Unix tool usually only tells about its own
    97 executable format, not the underlying platform!
    98 
    99 
   100 Dependable system tools
   101 -----------------------
   102 
   103 The following portable system tools can be taken for granted:
   104 
   105 * GNU bash as uniform shell on all platforms.  The POSIX "standard"
   106   shell /bin/sh is *not* appropriate, because there are too many
   107   non-standard implementations of it.
   108 
   109 * Perl as largely portable system programming language.  In some
   110   situations Python may serve as an alternative, but it usually
   111   performs not as well in addressing various delicate details of
   112   operating system concepts (processes, signals, sockets etc.).
   113 
   114 * Scala with Java 1.7.  Isabelle/Scala irons out many oddities and
   115   portability issues of the Java platform.
   116 
   117 
   118 Known problems
   119 --------------
   120 
   121 * Mac OS: If MacPorts is installed there is some danger that
   122   accidental references to its shared libraries are created
   123   (e.g. libgmp).  Use otool -L to check if compiled binaries also work
   124   without MacPorts.
   125 
   126 * Mac OS: If MacPorts is installed and its version of Perl takes
   127   precedence over /usr/bin/perl in the PATH, then the end-user needs
   128   to take care of installing extra modules, e.g. for HTTP support.
   129   Such add-ons are usually included in Apple's /usr/bin/perl by
   130   default.
   131 
   132 * The Java runtime has its own idea about the underlying platform,
   133   which affects Java native libraries in particular.  In
   134   Isabelle/Scala the function isabelle.Platform.jvm_platform
   135   identifies the JVM platform.  Since a particular Java version is
   136   always bundled with Isabelle, the resulting settings also provide
   137   some clues about its platform, without running it.