Although the term "supercomputer" may sound fanciful or exaggerated, it is simply an extremely fast mainframe that can execute trillions of calculations every second.
What is the antecedent? Why is it wrong?
Although the term "supercomputer" may sound fanciful or exaggerated, it is simply an extremely fast mainframe that can execute trillions of calculations every second.
What is the antecedent? Why is it wrong?
Although the term "supercomputer" may sound fanciful or exaggerated, it is simply an extremely fast mainframe that can execute trillions of calculations every second.
Taking this sentence in isolation, the antecedent is the term "supercomputer", so it is a word.
A word cannot be a mainframe computer, so it is simply a mainframe doesn't make sense.
The sentence would work if you changed the verb is for means:
Although the term "supercomputer" may sound fanciful or exaggerated, it simply means an extremely fast mainframe that can execute trillions of calculations every second.