Why is MMU required?

An MMU effectively performs virtual memory management, handling at the same time memory protection, cache control, bus arbitration and, in simpler computer architectures (especially 8-bit systems), bank switching.

What are the functional requirements of a multi-user operating system?

Multi-user operating systems are designed to have multiple terminals (monitor, keyboard, mouse, etc.) all connected to a single mainframe (a powerful CPU with many microprocessors) that allocates time for each user’s processing demands so that it appears to the users that they are all working simultaneously.

How does an operating system make your computer more secure?

Operating systems also use the concept of privileges to help protect and secure down a computer. As such, many operating systems these days do their best to lock down the privileges that a user has. This helps to lower any damage that can be caused by programs, if they exist.

Is it possible to build a processor without a virtual memory?

it is possible to run without virtual memory at all, just physical memory (in fact, most embedded systems run this way).

Why is TLB needed?

Translation Lookaside Buffer (i.e. TLB) is required only if Virtual Memory is used by a processor. In short, TLB speeds up the translation of virtual addresses to a physical address by storing page-table in faster memory. In fact, TLB also sits between CPU and Main memory.

What would happen if a CPU has no TLB?

If a page table entry is not found in the TLB (TLB miss), the page number is used as index while processing page table.

What resources does an operating system need to protect and secure?

Protection and security requires that computer resources such as CPU, softwares, memory etc. are protected. This extends to the operating system as well as the data in the system. This can be done by ensuring integrity, confidentiality and availability in the operating system.

How do operating systems perform system protection?

Protection refers to a mechanism which controls the access of programs, processes, or users to the resources defined by a computer system. We can take protection as a helper to multi programming operating system, so that many users might safely share a common logical name space such as directory or files.