A good answer might be:

A machine instruction is a pattern of bits that asks for one machine operation to be executed.

Setting up SPIM

Each MIPS machine instruction is 32 bits (four bytes) long. The three lines after main: call for three machine instructions. The remaining lines consist of information for the assembler and comments (for the human).

For this first program some SPIM options must be set. In the menu bar, click on Simulator then Settings to get the settings dialog. Select the following options:

ON Save window positions
ON General registers in hexadecimal
OFF Floating point registers in hexadecimal
OFF Bare machine
ON Allow pseudo instructions
ON Load exception file
OFF Delayed Branches
OFF Delayed Load
ON Mapped I/O
OFF Quiet

These settings simulate a bare machine with no user conveniences. Later we will include the conveniences.

QUESTION 6:

(Thought Question) Do most actual computers start up as a bare machine?