Cisco Cat OS, Hybrid OS, and Cisco IOS platform matrix
Platform	Cisco OS
Catalyst 6500 with MSFC or MSFC2	Either hybrid-mode(Hybrid OS) or Cisco IOS
Catalyst 6500 without an MSFC or MSFC2	Cisco CatOS
Catalyst 6500 with Supervisor Engine 720, PFC3, and MSFC3	Either hybrid-mode(Hybrid OS) or Cisco IOS
Catalyst 6500 with Supervisor Engine 32	Either hybrid-mode(Hybrid OS) or Cisco IOS
Catalyst 4000 or 4500 with Supervisor Engine II+, III, IV, V; Catalyst 4948	Cisco IOS
Catalyst 4912G	Ciso IOS(Layer 2-only platform)
Catalyst 4000 or 4500 with Supervisor Engine I or II	Ciso IOS(Layer 2-only platform)
Catalyst 3550, 3560 or 3750	Cisco IOS
Catalyst 3500XL	Ciso IOS(Layer 2-only platform)
Catalyst 2940, 2950, 2960, or 2970	Ciso IOS(Layer 2-only platform)
Catalyst 2948G, 2980G, or 2948-GE-TX	Ciso IOS(Layer 2-only platform)
2948G-L3 or 4908G-L3	Cisco IOS
Cisco Catalyst Express Switches	Cisco IOS