TSSFAR output shows that the Next Available Acid Number and the Last Available Acid Number are the same.
It appears that there are no more available Acid Numbers available but acids can still be created in one system.
In another system TSSFAR also shows that the Next Available Acid Number and the Last Available Acid Number are the same.
But this system received TSS0312E SECURITY FILE SEGMENT IS FULL.
Why did one system receive the TSS0312E message and the other did not?
Top Secret release 16.0
The Acid Index Entries Defined are the total number of entries available for acids to occupy. When your first secfile was created it had one acid and then every other entry was available. Eventually, you hit the last available acid number, chronologically filling each entry.
When you hit the last number, that does not mean that you no longer have available entries. Top Secret will go back and fill any entry numbers that have been vacated by deleting the acid that occupied that spot.
The Last Available Acid Number will always be the same as the Number of Acid Index Entries Allocated.
Once the Last Available Acid Number is used, the Next Available Acid Number and the Last Available Acid Number will always be the same until you increase the number of Acid Entries Available.
The stats that help to determine how many entries are still available are the ACID Index Entries Allocated and the number of Acid Index Entries Defined.
You would subtract the number of Acid Index Entries Defined from the number of ACID Index Entries Allocated.
ACID Index Entries Allocated - 40,000
Acid Index Entries Defined - - 27,000
Available Acid Index Entries = 13,000