I need to restore informix database(IDS 7.31 in Window NT4.0) from a
backup tape.

Below is my problem:
1. When I'm use warm restore 'ontape -r'.
It's show the error as below:

"When accessing a new tape of a multivolume partition, the current
blocksize is incorrect.
Invalid Archive Tape."

2. When I'm use cold restore 'ontape -r'.
It's show the error as below:

"C:\INFORMIX\bin>ontape -r
Please mount tape 1 on \\.\TAPE0 and press Return to continue ...
When accessing a new tape of a multivolume partition, the current
blocksize is incorrect.
Physical restore failed - function read archive backup failed
code -1 errno 0
Program over."

I am not sure how to tackle the problem above.
I have also make the 'TAPEBLK' for backup & restore in the same value

<Eg:
# System Archive Tape Device
TAPEDEV \\.\TAPE0 # Tape device path
TAPEBLK 20 # Tape block size (Kbytes)
TAPESIZE 8192000 # Maximum amount of data to put
on tape (Kbytes)>

But the same error still occur.

Any idea for what I can do?

probably not however:

if you have a linux machine where you can attach a tapedev to... try
and dd the first bit of to a file

eq

dd if=<tapedev> of=somefile bs=<blocksize used when backup was
created>k count=12

if you get an error you may try a different bloksize
anyways when it works run strings on the produced file;
in there you should find the correct blocksize. if it is different from
what you have used try to use that as blocksize for the restore or the
one which worked
when you did the 'dd'.
.... if that does not work you may have to look at archecker....
probably with help from TS.

Superboer.