[cwn] Attn: Development Editor, Latest Caml Weekly News

[Alan Schmitt]

Hello,

Here is the latest Caml Weekly News, for the week of November 03 to 10, 2009.

1) open-sourcing of the XAPI toolstack
2) Ocal IDE: Vote for OcalIDE
3) compiling C library wrapper
4) Camlight version 0.80
5) MetaOcaml and high-performance
6) Modules
7) Other Caml News

========================================================================
1) open-sourcing of the XAPI toolstack
Archive: <http://groups.google.com/group/fa.caml/browse_thread/thread/b19555a7e09f063c#>
------------------------------------------------------------------------
** Thomas Gazagnaire announced:

We are pleased to announce the open-sourcing of the XAPI toolstack, written in
OCaml, as used in the Citrix XenServer product line. The XAPI toolstack is
licensed under the LGPL v2.1 with a special static linking exception.

**context**

Xen [1] is an open-source type 1 hypervisor, providing the ability to run
multiple operating systems, called virtual machines, concurrently on a single
physical processor. Type 1 (or native, bare-metal) hypervisors are software
systems that run directly on host's hardware. They have been very popular
architecture since the CP/CMS, developed at IBM in the 1960s. Citrix XenServer
[2] is an enterprise-class, cloud-proven server virtualization platform that
delivers the critical features of live migration and centralized multi-server
management for Xen based virtual machine. XenServer is an open and powerful
server virtualization solution that radically reduces datacenter costs by
transforming static and complex datacenter environments into more dynamic,
easy to manage IT service delivery centers.

**xapi**

The xapi toolstack, which provides the core Citrix Xenserver's
functionalities, is a set of libraries and programs written in OCaml. It is
approximately 200k lines of code developed from early 2006. Within Citrix,
more than 40 people have already contributed to its source code.

What the XAPI toolstack has to manage covers a large range, from low-level
(interface with kernel and hypervisor) to high-level (distributed data/locking
management). It also need to have good performance because it may be used in
an environment of thousands of virtual machines per cluster and has to be able
to run on systems with limited resources (embedded editions of Citrix
XenServer are distributed on an USB stick and run in highly customized OS).
Finally, as a major enterprise product, the XAPI toolstack evolves constantly,
due to customer/business requests.

The OCaml language has been particularly good so far to help us facing all
this challenges, and we can't think of a better language to use :-) We really
appreciate that the compiler tools are stable, that the compiled code is fast
and small and that static-type inference makes our software robust to changes.

**links**

The released code is the current development version ("trunk") and is under
active development. The repositories are here:

<http://xenbits.xen.org/xapi/xen-dist-ocaml.hg> - scripts and Makefiles to build
some external library dependencies
<http://xenbits.xen.org/xapi/xen-api-libs.hg> - internal libraries (e.g. for
talking to xenstore)
<http://xenbits.xen.org/xapi/xen-api.hg> - the toolstack itself

The easiest way to build the code is in a specially-prepared VM, instructions
are here:

<http://xenbits.xen.org/xapi/install.html>