How to differentiate RHEL releases correctly

Please take note, this artical is only focusing on Server relate product, not Desktop product.

Before RHEL5, we usually talked about AS & ES for server editions.

• AS: Red Hat Enterprise Linux AS ("advanced server")
• ES: Red Hat Enterprise Linux ES ("entry/mid server")

Key limitations with RHEL3 ES (kernel foundation Linux 2.4.21)

• Maximum 2 CPU sockets
• Maximum 8 GB RAM
• No support on IBM Power

Key limitations with RHEL4 ES (kernel foundation Linux 2.6.9)

• Maximum 2 CPU sockets
• Maximum 8 GB RAM
• No support on IBM Power

Start with RHEL 5, Redhat starts to use "RHEL" and "RHEL Advanced Platform" to replace "ES" & "AS".

Key limitations with RHEL5 (kernel foundation Linux 2.6.18)

• Maximum 2 CPU sockets
• Maximum 4 virtualized guests/instances
• No support for Storage virtualization (with Red Hat GFS and Cluster Suite)

Reference:

http://www.redhat.com/rhel/compare/

http://www.redhat.com/whitepapers/rhel/RHEL3FamOverWPSO.pdf

http://www.tips5.com/difference-between-as-ws-es-and-desktop-of-redhat-enterprise-linux