dOS is a fork of Linux 2.6.24.7 that provides a Deterministic Process Group abstraction as described in our OSDI 2010 paper. Included in this source distribution is DDOS, which is a shim program for dOS that enables deterministic execution of unmodified distributed systems as described in our ASPLOS 2013 paper.

Not actively maintained. GPLv2 license except where noted.

• ddos-src.tar.gz   (warning: 123 MB)

Available here.

UW Academic License except where noted.

Typmix is a framework for implementing type systems. Typmix is implemented as a modified version of the extensible compiler Xoc. A snapshot of the most recent source code is available below.

Not actively maintained. MIT License except where noted.

• typmix.tar.gz   (last updated 2007)

For documentation, see my master's thesis and also see the Xoc paper. Below is a quick example of the simply-typed lambda calculus expressed in Typmix, abridged from simple.zeta in the above source tarball:

  extensible grammar Simple {
    expr: "(" expr ")"
        | expr expr
        | "fun" var ":" type "." expr
        | var

    type: "(" type ")"
        | type "->" type

    var: /[a-z][A-Za-z0-9_]*/a
  }

  typerules {
    ~expr{\x::var}        :: term.vars[x]
    ~expr{fun \x:\T1. \e} :: `{\T1 -> \T2}  { e :: T2 }
    ~expr{\e1 \e2}        :: T2             { e1 :: {\T1 -> \T2} && e2 :: T1 }
  }
       

MEEL, the Mailbox-driven Easy Event Language, is an extension to the C language that adds lightweight tasks and asynchronous message-passing via typed mailboxes. A runtime library layers a message-based interface on top of traditional I/O APIs such as epoll, enabling a simple, natural style of event-driven programming. See also EEL, tame, and tamer. A snapshot of the most recent source code is available below.

Not actively maintained. BSD License except where noted.

• meel.tar.gz   (last updated 2006)

Unfortunately there is (currently) no documentation available other than the source code itself. Below is a quick example that demonstrates the power of MEEL's language extensions together with its runtime library:

  EVENT server(MAILBOX<int> workqueue) {
    VARS {
      int fd;
      MAILBOX<void> rd;
      MAILBOX<void> timer;
    }

    fd = opensocket();
    listen(fd, 10);

    rd = meel_add_read(fd);
    timer = meel_add_timer(100);

    for (;;) {
      WAIT(rd) {
        int x = getdata(fd);
        NOTIFY(workqueue, x);
      }
      OR_WAIT(timer) {
        printf("timer fired");
      }
    }
  }