Firstly Ruby/Informix 0.5.1, the open source Ruby driver for Informix was released on Friday. Read about and download it here: http://rubyforge.org/projects/ruby-informix/. The main change in the release was a DATETIME HOUR TO SECOND bug fix.
Secondly the IBM_DB Ruby adapter and driver gem/plugin now supports Informix data servers. Here are the release notes for IBM_DB-0.8.0
IBM_DB adapter & driver gem refresh 0.8.0 including Informix Dynamic Server (IDS) support.
Changes:2007/07/11 (IBM_DB adapter 0.8.0, driver 0.7.0): - Support for Informix Dynamic Server 11.10 and beyond - New driver method get_last_serial_value to retrieve last inserted serial value for Informix Dynamic Server
Which Ruby driver should I use?
The key difference between the two drivers, apart from one being an independent open source project and one being developed by IBM, is the connection protocol used to connect to the data server, which also explains why the IBM driver only works with IDS 11.10 and later (and DB2).
Prior to 11.10, the only supported way for a client to communicate with IDS was via the SQLI protocol - the underlying protocol supported by the Client Software Development Kit (CSDK). In IDS 11.10 support for the DRDA protocol was added, paving the way for common clients for both IDS and DB2. The IBM Ruby driver uses DRDA, the open source Ruby driver uses SQLI.
If your IDS 11.10 instance is set up to use DRDA you have the choice of using either driver. If you are using the default SQLI configuration or an earlier version of IDS only the open source driver will work.
Personally I hope both drivers continue to be developed, it benefits everyone if an open source independent Ruby driver is available, and the SQLI communication protocol is going to be around for a long time. A similar situation exists with JDBC, where there is an IBM SQLI driver for Informix (current version 3.10) and a new DRDA driver available as part of the IBM Data Server Client.
I have a session entitled What's new in Informix application development at IOD 2007 in October where I'll expand on the recent SQLI and DRDA options for application developers. There are also other presentations and Developer Den sessions planned on Ruby on Rails, PHP/Python and the common client.