In The forerunner saga of the Halo books, the Gravemind uses something described as a "logic-virus" to turn machines to his side. The Halo Nation wiki article describes this as "altering every Forerunner AI's basic logical processes, causing it to aid the Flood cause. This 'Logic-Virus' was considered by the Forerunners to be the informational form of the Flood infection, to which Mendicant Bias was the first victim in its 43-year discourse with the Precursor Gravemind."
But the Gravemind also conversed with the Ur-Didact, telling him about the Precursors' relationship with the Forerunners, which affected him mentally, enough to cause him to (debatably) go insane- to the point where a once-decent man eventually tried to destroy humanity.
My question is, could the Gravemind simply have conversed with the Forerunners' machines at high-speed, convincing them to help him purely by telling the truth? Or was it an actual computer virus?