The supervised match is not the lab's only line

Lesson map

Lesson 05. Map, example, EX051.

flowchart TD
  A["Lab prints MATCH and MISMATCH"] --> B["Staff summary: the real download matched"]
  B --> C{"Is the bad lab file the library installer?"}
  C -->|No| D["Keep both lines and the summary"]
  C -->|Yes| E["That swap is not in the file"]

The laboratory pair and the supervised check answer different questions.

Logical drawing

lab_checkfile.py
    download_ok.bin MATCH
    download_bad.bin MISMATCH
    published prefix stays on that run
staff summary
    the supervised catalogue download matched
    it does not name download_bad.bin

Learning outcomes

After this chapter, you should be able to:

1. Keep both laboratory lines from the fingerprint check.
2. Keep the staff summary's supervised match.
3. Refuse to treat one of those records as the other.

5.1 Two checks sit side by side.

The embedded laboratory compares synthetic bytes. It prints download_ok.bin MATCH and download_bad.bin MISMATCH, under the prefix published: 215e60edb672063786f8bb92.... Chapter 4 then says Leo repeated the steps on the library's real catalogue download with Inês watching, and the five-sentence summary says that download matched. One classmate deletes the MISMATCH line and treats the laboratory as a single success. Another classmate reads MISMATCH as the fate of the installer the library actually fetched. Neither reading is the file. The synthetic bad file ends with a changed last byte inside the script. The staff page never calls the supervised download download_bad.bin. Leo leaves the printed pair where it is and leaves the summary's match where it is.

5.2 Worked example

Lesson table; scroll horizontally to read all columns →

Synthetic case. The laboratory filenames and the library's installer stay different objects.

Errors and limits

Keeping the MISMATCH line does not spoil the supervised match, and the match does not erase the laboratory pair.

Apply

• EX051 — Which file failed? The laboratory prints download_ok.bin MATCH and download_bad.bin MISMATCH. The staff summary says the supervised catalogue download matched. Was the library's installer the tampered laboratory file?
  Show marking criteria

  Rubric: 3 = no; both laboratory lines stay; the summary's match stays; the bad file is the synthetic tampered input; do not edit lab_checkfile.py;; 2 = the summary and the laboratory are different checks;; 1 = one line;; 0 = none.