[ILUG] Cheap large capacity tape drives

[Niall O Broin]

On Mon, Jun 26, 2000 at 02:47:02PM +0100, Wesley Darlington wrote:

> You said:
> > there's no real difference in cost
> > between a cheap tape drive e.g. Travan and an expensive tape drive e.g. DLT,
> > because the tape cartridges for a cheap tape drive are relatively very
> > expensive, so the cost of tape drive + enough cartridges is about the same
> > for either option).
> 
> ...in which you seem to be saying that the cartridges for a cheap drive
> are relatively expensive compared to the cartridges for an expensive
> drive. (DLT, I assumed). Which would imply that the cartridges for an
> expensive drive (ie. DLT cartridges) are relatively cheap compared to
> the cartridges for a cheap drive. Which is just a stone's throw away
> from calling DLT cheap. A bit tenuous, perhaps...

Just a tad . . .

> Anyway, *are* DLT cartridges cheaper per megabyte than cartridges for
> (say) travans...?  (clickety click)  Wow! They are. Best part of twenty
> quid for a 4GB/8GB travan cartridge. That'd be two hundred quid for
> 40GB/80GB, which compares badly to the sixty-odd quid a 35/70GB or
> a 40/80GB compatible DLT tape costs. (IV? V?)

Better comparison is with a 4GB DDS-II DAT tape which I suppose you can get
for about a fiver.  For a comprehensive backup regime (daily, weekly kept
for 12 weeks, monthly archived) you'd need 18 tapes (daily + weekly,
assuming 7 day) and you'd consume 12 tapes per year giving this matrix


System	Drive	Fixed tapes	Consumable tapes

Travan	200	360		240 / year
DAT	500	90		60  / year

I'm guessing a little at the drive costs - I think Travan may be a little
cheaper, but not having a taxpayer supplied fat pipe :-) I'm not going to
look right now. However, you can see the principle. I heard a very succinct
explanation of this - to get high data capacity, you must have high
precision, and you have the option to design this precision into the tape
cartridges or the tape drive. Wherever you put the precision, you put the
cost.


> Sorry, I was stuck in the "I've lots of data I want to take home" mentality.

No, this is work related.



Regards,


Niall