[Info-vax] strange backup behavior

[AEF]

On Aug 10, 4:22 pm, AEF <spamsink2... at yahoo.com> wrote:
> On Aug 10, 2:02 pm, B Hobbs <bdhobb... at acm.org> wrote:> On Aug 10, 10:10 am, AEF <spamsink2... at yahoo.com> wrote:
>
> > > On Aug 10, 11:48 am, B Hobbs <bdhobb... at acm.org> wrote:
> > > > On Aug 8, 9:42 am, AEF <spamsink2... at yahoo.com> wrote:
> > > > > On Aug 8, 9:07 am, sapienzaf <sapie... at noesys.com> wrote:
> > > > > > On Aug 7, 11:55 pm, David J Dachtera <djesys... at spam.comcast.net>
> > > > > > wrote:
>
[...]
>
> I'm experimenting with appending backup save sets on an 8mm drive. I
> have DLT, but no scratch tapes to play with. I'll report back when I'm
> done.
>
> AEF

Took a quick look at the .com file. Looks okay at this point. I'll
have to study it more, later.

Reporting back!  *** MAKE THAT 4MM DRIVES. ***

It's as I remember. The BACKUP picks up immediately at the EOF of the
previous one. The time for successive backups of the same files stays
about the same:

These are the execution times for BACKUP save operations of the same
files copied to the same tape, one after the other on the tape. I
think it's safe to say that BACKUP normally simply picks up on the
tape where it left off with the previous save set. No rewinding is
done without /REWIND.

Execution time: 00:01:51.08
Execution time: 00:01:38.38
Execution time: 00:01:12.68
Execution time: 00:01:36.35
Execution time: 00:00:59.96
Execution time: 00:01:18.73

Here's the gory session:

NODEX$ @SYSF:TIME BACK/NOASS/LOG SYS$MANAGER:FTSTARTUP.COM
MKA0:TEST_1.BCK/LABEL=AEFTST/GROUP=0/BLOCK=32256/COMM="Test at EOF"
TIME.COM begun at 2009-08-10 20:05:55.14
Running $ BACK/NOASS/LOG SYS$MANAGER:FTSTARTUP.COM MKA0:TEST_1.BCK/
LABEL=AEFTST/GROUP=0/BLOCK=32256/COMM="Test at EOF"
%BACKUP-W-NOFILES, no files selected from NODEX$DKA200:[SYS0.][SYSMGR]
FTSTARTUP.COM;*
%BACKUP-S-COPIED, copied NODEX$DKA200:[SYS0.SYSCOMMON.][SYSMGR]
FTSTARTUP.COM;354
%BACKUP-S-COPIED, copied NODEX$DKA200:[SYS0.SYSCOMMON.][SYSMGR]
FTSTARTUP.COM;353
%BACKUP-S-COPIED, copied NODEX$DKA200:[SYS0.SYSCOMMON.][SYSMGR]
FTSTARTUP.COM;352
[...]
%BACKUP-S-COPIED, copied NODEX$DKA200:[SYS0.SYSCOMMON.][SYSMGR]
FTSTARTUP.COM;124
%BACKUP-S-COPIED, copied NODEX$DKA200:[SYS0.SYSCOMMON.][SYSMGR]
FTSTARTUP.COM;123
%BACKUP-S-COPIED, copied NODEX$DKA200:[SYS0.SYSCOMMON.][SYSMGR]
FTSTARTUP.COM;122
Execution time: 00:01:51.08
TIME.COM ended at 2009-08-10 20:07:46.22
NODEX$ @SYSF:TIME BACK/NOASS SYS$MANAGER:FTSTARTUP.COM MKA0:TEST_2.BCK/
LABEL=AEFTST/GROUP=0/BLOCK=32256/COMM="Test at EOF"
TIME.COM begun at 2009-08-10 20:13:29.47
Running $ BACK/NOASS SYS$MANAGER:FTSTARTUP.COM MKA0:TEST_2.BCK/
LABEL=AEFTST/GROUP=0/BLOCK=32256/COMM="Test at EOF"
%BACKUP-W-NOFILES, no files selected from NODEX$DKA200:[SYS0.][SYSMGR]
FTSTARTUP.COM;*
Execution time: 00:01:38.38
TIME.COM ended at 2009-08-10 20:15:07.86
NODEX$ @SYSF:TIME BACK/NOASS SYS$MANAGER:FTSTARTUP.COM MKA0:TEST_3.BCK/
LABEL=AEFTST/GROUP=0/BLOCK=32256/COMM="Test at EOF"
TIME.COM begun at 2009-08-10 20:15:18.17
Running $ BACK/NOASS SYS$MANAGER:FTSTARTUP.COM MKA0:TEST_3.BCK/
LABEL=AEFTST/GROUP=0/BLOCK=32256/COMM="Test at EOF"
%BACKUP-W-NOFILES, no files selected from NODEX$DKA200:[SYS0.][SYSMGR]
FTSTARTUP.COM;*
Execution time: 00:01:12.68
TIME.COM ended at 2009-08-10 20:16:30.85
NODEX$ @SYSF:TIME BACK/NOASS SYS$MANAGER:FTSTARTUP.COM MKA0:TEST_4.BCK/
LABEL=AEFTST/GROUP=0/BLOCK=32256/COMM="Test at EOF"
TIME.COM begun at 2009-08-10 20:22:25.87
Running $ BACK/NOASS SYS$MANAGER:FTSTARTUP.COM MKA0:TEST_4.BCK/
LABEL=AEFTST/GROUP=0/BLOCK=32256/COMM="Test at EOF"
%BACKUP-W-NOFILES, no files selected from NODEX$DKA200:[SYS0.][SYSMGR]
FTSTARTUP.COM;*
Execution time: 00:01:36.35
TIME.COM ended at 2009-08-10 20:24:02.22
NODEX$ @SYSF:TIME BACK/NOASS SYS$MANAGER:FTSTARTUP.COM MKA0:TEST_4.BCK/
LABEL=AEFTST/GROUP=0/BLOCK=32256/COMM="Test at EOF"
TIME.COM begun at 2009-08-10 20:31:50.00
Running $ BACK/NOASS SYS$MANAGER:FTSTARTUP.COM MKA0:TEST_4.BCK/
LABEL=AEFTST/GROUP=0/BLOCK=32256/COMM="Test at EOF"
%BACKUP-W-NOFILES, no files selected from NODEX$DKA200:[SYS0.][SYSMGR]
FTSTARTUP.COM;*
Execution time: 00:00:59.96
TIME.COM ended at 2009-08-10 20:32:49.96
NODEX$ @SYSF:TIME BACK/NOASS SYS$MANAGER:FTSTARTUP.COM MKA0:TEST_6.BCK/
LABEL=AEFTST/GROUP=0/BLOCK=32256/COMM="Test at EOF"
TIME.COM begun at 2009-08-10 20:33:49.44
Running $ BACK/NOASS SYS$MANAGER:FTSTARTUP.COM MKA0:TEST_6.BCK/
LABEL=AEFTST/GROUP=0/BLOCK=32256/COMM="Test at EOF"
%BACKUP-W-NOFILES, no files selected from NODEX$DKA200:[SYS0.][SYSMGR]
FTSTARTUP.COM;*
Execution time: 00:01:18.73
TIME.COM ended at 2009-08-10 20:35:08.18
NODEX$

AEF