Something strange when full offline backup

Hello,
I have a question and need some help.
My database is Oracle7.3 on Netware4.10. The database is in archivelog mode,
and I do full offline backup every night. My step is:

22:00 shutdown immediate
22:05 copy oranw\database\*.*  d:\backup
00:00 startup

My problem is :
After shutdown and copy *.* d:\backup,
and I check all files in d:\backup next morning, I found the time of log1orcl.dbf is different from other files. Here is the list of d:\backup:

ctl1orcl.ora             230K    1998/10/8 PM 10:00
log1orcl.ora           200K    1998/10/8 PM 01:36
log2orcl.ora           200K    1998/10/8 PM 10:00
rbs1orcl.ora        5,122K    1998/10/8 PM 10:00
sys1orcl.ora     10,242K    1998/10/8 PM 10:00
sys2orcl.ora     30,722K    1998/10/8 PM 10:00
tmp1orcl.ora       7,170K    1998/10/8 PM 10:00
usr1orcl.ora      13,314K    1998/10/8 PM 10:00
usr2orcl.ora    102,402K    1998/10/8 PM 10:00

Only log1orcl.ora update time is different. I check the alert file,there's no error about shutdown and startup. Does d:\backup\*.* work for recovery?
(I'm so afraid it can't use for recovery!) Please give me some tips.
I'll appreciate for your help.
Please Cc to : violin.hsiao_at_mail.pouchen.com.tw,Thanks.

Violin. Received on Thu Oct 08 1998 - 21:38:48 CDT