Is using ASM a pre-requisite for RAC? I am about to build our first RAC development environment, and as I'm new to RAC and have not used ASM I wanted to keep things as simple as possible.

I was under the impression that ASM is a pre-requisite of RAC, but reading I've done recently implies it's optional (although ASM offers better performance particularly on reads).

So is a non-ASM RAC environment supported by Oracle? We are using 11.2.0.4 on a RedHat Linux 6 environment.
i've found the definitive answer from the oracle docs

http://docs.oracle.com/cd/E11882_01/license.112/e47877/editions.htm#DBLIC109

in the Oracle Database Standard Edition and Oracle Real Application Clusters (Oracle RAC) section, it specifies

"Oracle Automatic Storage Management is required for creating and managing all Oracle database file types. Raw volumes, partitions, or third-party cluster file systems are not supported for storing Oracle database files with Oracle Standard Edition and Oracle RAC"