Exercise 1: The Gap Left by the Other Five Courses — Possible Solution
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WHAT EACH COURSE ASSUMES, PER THIS CHAPTER
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log1 assumes "a way to read the logs"; netdiag1 assumes "a terminal to
run ping, dig, nc from"; perfdiag1 assumes "a shell already open on the
machine being diagnosed"; appdiag1 assumes "database and application
access already granted"; incident1 assumes "that the whole team
already has whatever access the incident needs."

THE COMMON THREAD ACROSS ALL FIVE
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Per this chapter, "every command in this subject's other five
courses... assumed a terminal was already open on the right machine."
Regardless of which specific technical layer each course teaches you
to diagnose, all five start from the same unstated premise: you're
already connected to the system in question, with whatever access
level the task requires.

WHY THIS LEAVES A GENUINE GAP
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Per this chapter, "none of them teach how that access actually gets
established. This course fills exactly that gap." Knowing how to read
a pg_stat_activity output or run a netdiag1-style port check is useless
if you can't actually get a session open on the right machine in the
first place - the five existing courses' own techniques all depend on
a step none of them cover.

WHY THIS WORKS AS AN ANSWER
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It correctly restates what each of the five courses assumes using the
chapter's own table, identifies the shared unstated premise across all
of them, and explains specifically why that premise being unaddressed
creates a real gap this course is positioned to fill.