Depends on how it's structured, doesn't it? It's entirely possible that programs and data will share the same memory with no sandboxing between programs. In t

Depends on how it's structured, doesn't it? It's entirely possible that programs and data will share the same memory with no sandboxing between programs. In that case, then without some sort of MMU a virus could just inject code into an otherwise benign program. Even with finer program access controls, it would still be hard to protect as long as untrusted code was allowed to alter trusted.