[Info-vax] strange backup behavior

[AEF]

On Aug 10, 6:33 pm, B Hobbs <bdhobb... at acm.org> wrote:
> On Aug 10, 1:42 pm, AEF <spamsink2... at yahoo.com> wrote:
>
>
>
> > On Aug 10, 4:22 pm, AEF <spamsink2... at yahoo.com> wrote:
>
> > 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
>
> Thank you AEF for the figures, a few questions though:
>
>   How much was backed up?  Blocks or bytes?

DCL>
DCL> D FTSTARTUP.COM/TOTAL

Directory SYS$COMMON:[SYSMGR]

Total of 152 files, 25460/26100 blocks.
DCL>

>   This was to a 4mm drive, what brand/model?

Magtape FTMKT3$MKA0:, device type DEC TLZ09, is online, allocated,
deallocate on
    dismount, mounted foreign, record-oriented device, file-oriented
device,
    error logging is enabled, controller supports compaction
(compaction
    disabled).

>   This was a real VAX?

Yes: MicroVAX 3100 Model 95

>   Which VMS version?

VMS V6.2

>
> If someone with the Charon-VAX emulator could confirm that I'm not the
> only one with this behaviour ...

I've never seen a tape rewind when starting a backup at the end of the
last save set.

AEF