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Last modified: 22 August 2023


Platform Support

CIAO 4.15.2 is available as precompiled binaries for the following platforms:


The Linux builds are done on a CentOS 7 machine and additionally tested on Ubuntu 18.04LTS. The Linux build will not work on some older Linux operating systems, including CentOS 6 and earlier versions of Fedora or Ubuntu.

CIAO 4.15.2 does not run on standard installations of:

  • Any 32 bit Linux
  • Cent OS6
  • RHEL version 6 or lower
  • Any version of Windows
Windows Subsystem for Linux (WSL)

CIAO is not supported using any Linux distribution running under the Windows Subsystem for Linux (WSL). The CXC has not done any formal testing with this configuration.

Mac OS

CIAO is built on macOSX 10.15 (Catalina) and is compatible with newer versions of macOSX through Ventura (13).

macOS 13 Ventura and M1/M2 chip support

The CXC has done standard testing with CIAO 4.15.2 on macOSX 13 (Ventura) with an x86 (Intel) processor. We did not find any issues with either the conda edition or the ciao-install editions with this configuration. The CXC does not expect there to be any problems running CIAO 4.15.2 using macOS Ventura with Apple ARM64 (M1|M2) under Rosetta2. As with any problems, users with this system setup should contact CXC Helpdesk if they find any issues. The CXC has plans to fully test this configuration and will report any problems to the community.

The CXC has also done standard testing with CIAO 4.15.2 on macOS 11 (Big Sur) and macOS 12 (Monterey) running on the Apple M1 chip using Apple's Rosetta2 emulation layer to provide support for this architecture. Please note:

  • conda users will need to use the Intel x86_64 edition of conda and Python. The ARM64 (M1/M2) builds of Python available on conda-forge are not compatible.

  • Users who install CIAO with ciao-install needing to build MARX will have better luck installing the GCC compilers since the C-LANG compiler in Big Sur has broken the standard build process (for many applications). Users can install GCC from

  • User may find some slight numerical differences when comparing results between Intel x86_64 and Apple ARM64 (M1|M2) processors. This can affect things like wavdetect which may include|exclude sources near the significance threshold.

  • SAOImage ds9 v8.4.1 which is included with CIAO 4.15.2 works on both architectures (compatible with M1/M2 via Rosetta2).

The CIAO system depends on a number of 3rd party software packages or off-the-shelf software (OTS) and not all of these have native Apple ARM support (at the time of the release of CIAO 4.15.2). The CXC will monitor the situation.

CIAO users upgrading to macOSX Catalina and later may be inhibited by Apple's latest security settings which restrict some applications access to folders in users' home directories. The watchout page has some suggestions to help.

Explanation of Platform Support

The CXC's commitment to support a platform - i.e. a version of an operating system - means that we undertake to fix bugs on that system. This requires that we are able to compile CIAO from source on each platform, which is a much greater commitment than simply providing a compatible binary. Additionally, it is typically necessary to support several versions of each operating system: former, current and new.

When we support a system:

  1. We test every tool on every platform via a large number of regression tests and scripts; this requires a greater amount of time when the number of systems increases.
  2. We have to have current machines running each of these systems.
  3. We make a tarball and install it on each system; this process is never problem-free, and takes manpower and time.

As a result, we are not able to support a larger number of systems than we currently do. We gather information from users on what platforms they are running (or want to use) in order to prevent the overextension of our resources. Please contact the CXC Helpdesk if you have input you would like the CXC to consider for the next release of CIAO.