Tom,
Thank you for taking my question:

My question is regarding "alter system checkpoint" after removing a
data file for backup and recovery testing. The steps I did are:

I have an online backup of all files:
Init.ora paramater FAST_START_MTTR_TARGET is set to 20 minutes.

1- create table abc (f1 number(10))
tablespace my_test_ts;
2) insert some data into it:
begin
for i in 1..1000 loop
insert into abc values(i);
end loop
commit;
end;
/

3) I recycled through all my redo log groups:
alter system switch logfile;
4) From the operating system, I removed the data file for the table
5) I forced a check point, expecting oracle will tell me
that the data file doesn't exist:
alter system check point;
6) I inserted more data into the table (Same as in step 2)

I kept inserting data but, still without failure.

Why doesn't forcing a check point trigger that the data file doesn't exist?
How do I force it so that the error gets generated immediately?

The only way I forces it was during "alter tablespace .." or during a shutdown.

I would appreciate your help or input in this.

Thank you and, your new book is excellent!!