Here's a system audit manual from Jan 2000, part of the inquiry evidence. Lets figure out how this thing worked.
https://www.postofficehorizoninquiry.org.uk/evidence/pol0002...
https://www.postofficehorizoninquiry.org.uk/evidence/pol0002...
An interesting incidence/problem report is in [2] at 1h:03m:00s, where an replication error in their Riposte message store system is described. After a defect counter hardware was replaced, it will fill its empty store with messages from other counters.
[1] "Technical Appendix to Judgment (No.6) “Horizon Issues”", https://www.judiciary.uk/wp-content/uploads/2022/07/bates-v-...
[2] "Alvin Finch - Richard Coleman - Day 54 AM (17 May 2023) - Post Office Horizon IT Inquiry", https://www.youtube.com/watch?v=H0_-ebCVU5k&t=3780
[3] Steven Murdoch: "What went wrong with Horizon: learning from the Post Office Trial", https://www.benthamsgaze.org/2021/07/15/what-went-wrong-with...