Admin/PLATFORMS
author wenzelm
Fri Oct 24 11:30:39 2014 +0200 (2014-10-24)
changeset 58780 1f8c0da85664
parent 55438 3b95e70c5cb3
child 59114 8281f83d286f
permissions -rw-r--r--
discontinued python from standard system environment;
     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 X Lion (macbroy6)
    37                     Mac OS X Mountain Lion (macbroy30)
    38                     Mac OS X Mavericks (macbroy2)
    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 
    45 Fringe platforms like BSD or Solaris are unsupported.
    46 
    47 
    48 32 bit vs. 64 bit platforms
    49 ---------------------------
    50 
    51 Most users have 64 bit hardware and are running a 64 bit operating
    52 system by default.  For Linux this usually means missing 32 bit shared
    53 libraries, so native x86_64-linux needs to be used by default, despite
    54 its doubled space requirements for Poly/ML heaps.  For Mac OS X, the
    55 x86-darwin personality usually works seamlessly for C/C++ programs,
    56 but the Java 7 platform is only available for x86_64-darwin.
    57 
    58 Add-on executables are expected to work without manual user
    59 configuration.  Each component settings script needs to determine the
    60 platform details appropriately.
    61 
    62 The Isabelle settings environment provides the following variables to
    63 help configuring platform-dependent tools:
    64 
    65   ISABELLE_PLATFORM64  (potentially empty)
    66   ISABELLE_PLATFORM32
    67   ISABELLE_PLATFORM
    68 
    69 The ISABELLE_PLATFORM setting variable refers to the 32 bit version of
    70 the platform, even on 64 bit hardware.  Using regular bash notation,
    71 tools may express their preference for 64 bit with a fall-back for 32
    72 bit as follows:
    73 
    74   "${ISABELLE_PLATFORM64:-$ISABELLE_PLATFORM32}"
    75 
    76 Moreover note that ML and JVM usually have a different idea of the
    77 platform, depending on the respective binaries that are actually run.
    78 Poly/ML 5.5.x performs best in 32 bit mode, even for large
    79 applications, thanks to its sophisticated heap management.  The JVM
    80 usually works better in 64 bit mode, which allows its heap to grow
    81 beyond 2 GB.
    82 
    83 The traditional "uname" Unix tool usually only tells about its own
    84 executable format, not the underlying platform!
    85 
    86 
    87 Dependable system tools
    88 -----------------------
    89 
    90 The following portable system tools can be taken for granted:
    91 
    92 * GNU bash as uniform shell on all platforms.  The POSIX "standard"
    93   shell /bin/sh is *not* appropriate, because there are too many
    94   non-standard implementations of it.
    95 
    96 * Perl as largely portable system programming language, with its
    97   fairly robust support for processes, signals, sockets etc.
    98 
    99 * Scala with Java 1.7.  Isabelle/Scala irons out many oddities and
   100   portability issues of the Java platform.
   101 
   102 
   103 Known problems
   104 --------------
   105 
   106 * Mac OS X: If MacPorts is installed there is some danger that
   107   accidental references to its shared libraries are created
   108   (e.g. libgmp).  Use otool -L to check if compiled binaries also work
   109   without MacPorts.
   110 
   111 * Mac OS X: If MacPorts is installed and its version of Perl takes
   112   precedence over /usr/bin/perl in the PATH, then the end-user needs
   113   to take care of installing extra modules, e.g. for HTTP support.
   114   Such add-ons are usually included in Apple's /usr/bin/perl by
   115   default.
   116 
   117 * The Java runtime has its own idea about the underlying platform,
   118   which affects Java native libraries in particular.  In
   119   Isabelle/Scala the function isabelle.Platform.jvm_platform
   120   identifies the JVM platform.  Since a particular Java version is
   121   always bundled with Isabelle, the resulting settings also provide
   122   some clues about its platform, without running it.
   123 
   124 * Common Unix tools like /bin/sh, /bin/kill, sed, ulimit are
   125   notoriously non-portable an should be avoided.