Bonjour Jim,

Le mardi 14 septembre 2004 à 21:53:00, vous écriviez :

> All that said, what is the advantage of a serial medium? I gave up
> watching tape prices long ago, but my impression is that cost per bit on
> a cheap IDE drive rivals or exceeds the cost per bit of the most cost
> effective tapes. A $129 250 GB disk (yesterday's Sunday flyer price)
> plus a $15 tray is a might attractive combination. Even having conceded
> that the implementation is nothing, does support for serial devices make
> sense any more?

I'd say for mobility reasons. Storing a tape away (or shipping it at
some remote location) is probably still more easy than shipping a disk
in its tray.

See for instance HP Ultrium devices (LTO technology), from roughly 200
to 450 GB of data per tape with writing speeds of roughly 50 to 60 GB
per hour. A 200 GB cartridge is about 30 USD. True the drive itself is
around 2,000 USD. You get more than 10 disks and trays for that price.
But I think the cartridge still wins on mobility.

For my kind of useage, it really makes sense in big data-centers. When I
host servers at big operators premises, they often already have robots
with tens of tape drives and thousands of tape cartridges to automate
backup of customers. The backup is often offered in two services
variants. One where they backup your disks as is (the clone to disk
would be okay), one where they let you pipe a stream to a process
which actually route the stream to one of their tape somewhere else on
the network. But that is a quite specific configuration after all. For
a very wide range of users and applications, cloning to spare disks
could be very affordable and easy. And I could tape the spare disk
itself afterwards. ;-)

--
Cordialement,
Olivier Mascia