Admin/PLATFORMS
author wenzelm
Sat Sep 30 13:13:55 2017 +0200 (23 months ago)
changeset 66728 ae332cd13955
parent 66691 a8703e8ee1d3
child 66732 e566fb4d43d4
permissions -rw-r--r--
x86-cygwin for tools is no longer supported;
     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 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 
    81 There is a second set of settings for native Windows (instead of the
    82 POSIX emulation of Cygwin used before):
    83 
    84   ISABELLE_WINDOWS_PLATFORM64  (potentially empty)
    85   ISABELLE_WINDOWS_PLATFORM32
    86   ISABELLE_WINDOWS_PLATFORM
    87 
    88 It can be used like this:
    89 
    90   "${ISABELLE_WINDOWS_PLATFORM:-$ISABELLE_PLATFORM}"
    91 
    92   "${ISABELLE_WINDOWS_PLATFORM64:-${ISABELLE_WINDOWS_PLATFORM32:-${ISABELLE_PLATFORM64:-$ISABELLE_PLATFORM32}}}"
    93 
    94 
    95 Moreover note that ML and JVM usually have a different idea of the
    96 platform, depending on the respective binaries that are actually run.
    97 Poly/ML 5.6.x performs best in 32 bit mode, even for large
    98 applications, thanks to its sophisticated heap management.  The JVM
    99 usually works better in 64 bit mode, which allows its heap to grow
   100 beyond 2 GB.
   101 
   102 The traditional "uname" Unix tool only tells about its own executable
   103 format, not the underlying platform!
   104 
   105 
   106 Dependable system tools
   107 -----------------------
   108 
   109 The following portable system tools can be taken for granted:
   110 
   111 * Scala on top of Java 8.  Isabelle/Scala irons out many oddities and
   112   portability issues of the Java platform.
   113 
   114 * GNU bash as uniform shell on all platforms.  The POSIX "standard"
   115   shell /bin/sh does *not* work -- there are too many non-standard
   116   implementations of it.
   117 
   118 * Perl as largely portable system programming language, with its
   119   fairly robust support for processes, signals, sockets etc.
   120 
   121 
   122 Known problems
   123 --------------
   124 
   125 * Mac OS X: If MacPorts is installed there is some danger that
   126   accidental references to its shared libraries are created
   127   (e.g. libgmp).  Use otool -L to check if compiled binaries also work
   128   without MacPorts.
   129 
   130 * Mac OS X: If MacPorts is installed and its version of Perl takes
   131   precedence over /usr/bin/perl in the PATH, then the end-user needs
   132   to take care of installing extra modules, e.g. for HTTP support.
   133   Such add-ons are usually included in Apple's /usr/bin/perl by
   134   default.
   135 
   136 * The Java runtime has its own idea about the underlying platform,
   137   which affects Java native libraries in particular.  In
   138   Isabelle/Scala the function isabelle.Platform.jvm_platform
   139   identifies the JVM platform.  Since a particular Java version is
   140   always bundled with Isabelle, the resulting settings also provide
   141   some clues about its platform, without running it.
   142 
   143 * Common Unix tools like /bin/sh, /bin/kill, sed, ulimit are
   144   notoriously non-portable an should be avoided.