solution: The largest eight-digit base 2 integer is 1 less than the smallest nine-digit base 2 integer, which is $$ 100000000_{2} = 1 \cdot 2^8 = 256. $$Thus, the largest eight-digit base 2 integer is $256 - 1 = \boxed{255}$.
prompt.content: <|im_start|>system
  You are a helpful assistant.<|im_end|>
  <|im_start|>user
  What's the largest eight-digit base 2 integer?  Express your answer in base 10.
  Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
  <|im_start|>assistant
  
prompt.role: user
extra_info.answer: 255
extra_info.question: What's the largest eight-digit base 2 integer?  Express your answer in base 10.
extra_info.split: test