[Info-vax] Modern VMS (e.g. V8.4) tape installation?

[Paul Sture]

On Sun, 29 Apr 2012 20:28:39 -0400, David Froble wrote:

> Now I'm impressed.  20 years and the tapes still being readable isn't a
> bet I'd have made.

I was certainly confident I could read DLT tapes 10 years later, but 
perhaps not those which had been used for daily backups for a protracted 
length of time.
 
> Tapes were (in my experience) good for short term backup and such, short
> term being in months, not decades.  But now time seems to stretch out,
> and with old devices, and sometimes horrible media (you get what you pay
> for) and too many stories about degradation of the magnetic tape media,
> I just don't attempt to use tapes any more.

There is a small industry devoted to recovering tapes and putting their 
contents onto new media.  Think expensive seismological surveys here.  
These folks can do ordinary data tapes, but their main bread and butter 
is from the oil industry.

> For my current usage, which is mainly personal, nightly image backups to
> disk, and periodic movement of save sets to a removable disk and storage
> of same elsewhere seems to work.
> 
> I have lost a few 50 pin SCSI disks, but restore the image save set on
> another disk seems to have worked well.  Big problem is when I run out
> of spare disks ....
> 
> If you're talking real long term, I don't think anything can be
> considered reliable.

It's not just reliability but the availability of hardware (and suitable
device drivers) to read older media types.  The BBC's Domesday project
was recorded on 1986 technology laser discs and apparently they had
quite a problem reading that data once the idea of putting it online
came around.

http://www.bbc.co.uk/history/domesday

http://en.wikipedia.org/wiki/BBC_Domesday_Project#Preservation

"In 2002, there were great fears that the discs would become unreadable
as computers capable of reading the format had become rare and drives
capable of accessing the discs even rarer. Aside from the difficulty of
emulating the original code, a major issue was that the still images had
been stored on the laserdisc as single-frame analogue video, which were
overlaid by the computer system's graphical interface. The project had
begun years before JPEG image compression and before truecolour computer
video cards had become widely available.

However, the BBC later announced that the CAMiLEON project (a partnership
between the University of Leeds and University of Michigan) had developed
a system capable of accessing the discs using emulation techniques.[6]
CAMiLEON copied the video footage from one of the extant Domesday
laserdiscs. Another team, working for the UK National Archives
(who hold the original Domesday Book) tracked down the original 1-inch
videotape masters of the project. These were digitised and archived to
Digital Betacam."

> 
> As for the writable and re-writable CDs and DVDs, don't leave them in
> the sunlight ....

Just keep shifting the data around...

-- 
Paul Sture