Probably more obscurity than actual security, in my experience. I once knocked off about 10k users off of a dev mainframe LPAR simply by running a SQL query (cr

Probably more obscurity than actual security, in my experience. I once knocked off about 10k users off of a dev mainframe LPAR simply by running a SQL query (crashed DB2 and the underlying OS). With someone with more experience than I had, probably could have been exploitable. It was an accident, but it happened. Mainframes weren't nearly as rock solid as their reputation in the 3 years of dealing with them that I had. Mainframes were great at processes that need high IO. I've not dealt with them in close to 20 years, so dont know how current x64 linux or Windows stacks line up. Mainframes are hugely expensive. 20 years ago, entry level for the hardware was around $500k, IIRC. Dont think that even provided storage or software licenses. But, yeah, youve got one largely extremely reliable piece of big iron that can handle nearly all of your needs.