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Re: Re: capacity of magnetic media

Subject: Re: Re: capacity of magnetic media
From: Walter Knapp <>
Date: Sun, 21 Dec 2003 20:23:57 -0500
From: Jeremiah Moore <>
>
> True enough about the unknown longterm reliability of optical media.
> I use it for project archives, and have had good luck so far (knock
> on wood).  I can certainly imagine putting hard disks in the vault
> too, and imagine I'll go this way one of these days.  Wiebetech makes
> a firewire/usb2 adapter for raw ATA drive mechanisms which seems
> perfect for the task:
> http://www.wiebetech.com/products.html#drivedockproducts
>
> My sound library originates on DAT and MD, with originals filed away;
> the working library is on firewire drives with a redundant backup.
> 146GB as of today.  It's selectively backed up to DVD-R as well.

Before we toss optical media, I should note that the media discussed so
far is not the real archival optical media. That I consider to be the
true optical disks. The most durable and reliable format available. The
one that things like banks and so on depend on for their ultimate
backup. Though they too are being sucked into keeping arrays of hard
disks spinning.

That is the media I use for my main archive. 3.5" optical disks. I've
been using them for more than 10 years now. I've yet to have a failure
of media or drive. I do expect that at some point I will have a problem
if the current trend to believe that archival optical media means CD-R's
continue. The real optical format is not mainstream with consumer
computing in the US. Though much more common in other parts of the world.

I do maintain a copy of my stuff on audio CD as well. Seven years and
counting, and none of those have failed. Audio CD is not a computer tied
format, so has a greater chance of surviving longer as a format. I am
very careful how I burn them.

And, of course since I record on MD, which is about as good as real
opticals, I file away the originals of those too.

I would hope that those putting their collection on hard disks are doing
it redundantly. Modern hard disks are pretty durable, but not failproof,
and failures are often with no warning.  I use a array of Ultra 160 SCSI
hard disks as my second level of backup/working copy, mostly because
it's convenient to have everything readily available. I don't bother
with the slow USB disks, and don't trust the firewire ones, which are
often cobbled together out of older ATA drives and conversion chipsets.
I note that included with Apple's latest 10.3.2 update was a note that
choosing the wrong firmware with one particular chipset would result in
suddenly loosing the contents of the firewire disk. With the Ultra 160's
I've found it advisable to build some custom enclosures that cool the
disks better than stock enclosures. 10k rpm disks tend to produce more
heat and my disks are early generations of that speed. Of course my
backup disks are only turned on and spun up as needed. My G4 has a total
of 8 disks connected,  over 700GB, though that's not all audio backup. I
also maintain two independent working clones of my main hard disk which
I can boot from any time I need to. Those on a rotating schedule of
update from the main OS10.3 system disk. It's more complicated to have
reliable backup of OSX than it was with the Mac OS.

Currently I'm only buying Ultra 320 hard disks and associated hardware.
The price on that is not as bad as it used to be. About the time I go
with a G5, I'll probably convert entirely to Ultra 320.

Of course I'm told the way we are supposed to go is to one of the
companies that will maintain our backups for us. Via the internet on
large enterprise class disk arrays. But I kind of like to do it all
myself. And to use such a system you better have a very fast connection.

> In the long term, support does tend to be a fiction.  Products cease
> to be produced; companies disappear.  This is why I use commodity
> formats - it's more likely there will be some kind of support down
> the road.  (Everybody better copy your stuff off of those ultra-cool
> 3.5" floppy disks now!)

Support is a timed thing, not forever. You work probabilities. How
likely it will be supported for how long. At the bottom of the list is
the hobbiest/open source/freeware stuff which is in a constant state of
change, at the top is the formats in widest commercial circulation. You
have to be constantly aware of the status of all the formats and
hardware you use. By careful choice for these you can minimize, but not
eliminate the times you have to convert everything.

Macs dropped floppy disks a while back. Though you can still read most
of the older mac formats (or PC ones) with a add on USB floppy. I'm
mostly using USB based solid state memory for sneakernet chores now.
Very convenient for those temporary chores. I dropped keeping anything
important on floppies when I first went with optical disks long ago. I
was using a mac plus then, still have it, but don't start it up much.
But I have it's entire system, apps and so on preserved on optical disk.
I could boot it up from one of those.

Using 3.5" opticals gives me a use for those old floppy storage cases. A
3.5" optical is the size of two stacked 3.5" floppies.

The future will remember this time period as a blank. Little will
survive out of it in the way of graphics, sound, text etc. Because so
little thought is given to preserving it for the future. We have the
actual photographic negatives and prints from the civil war. How much of
the computer/digital camera photographs will survive that long?

> Sometimes it seems like technology in general is a carefully
> constructed fiction... the closer you get to the metal, the more you
> realize that it's amazing this stuff works at all.

In the case of computers finding out just how real commercial
programming and hardware design is done is very scary. It's a myth that
it's all this well contrived perfection. It's the first patchwork that
works that gets used.

Walt




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