On Mon, 28 Apr 2014 09:59:42 +0100 (BST), "Dave Liquorice"
wrote:

On Mon, 28 Apr 2014 01:40:04 +0100, Johny B Good wrote:

I regard not only CD as pre-historic but DVD and Blu-Ray[1] too. It's
not that that makes me feel old, just the effects of old age creeping
up on me.

Presumably old age is having its normal affect on hearing and sight
so you don't notice how crap downloads and/or streaming are compared
to CD or Blu-Ray (or even DVD come to that). B-)

Well, there's some small element of truth in what you say[1] but the
point I was making was that it seems so futile to 'archive' gigabyte's
worth of audio and terabyte's worth of TV recordings and mpeg movies
onto optical disk media of questionable durability and limited
capacity.

As a backup medium (other than for bootable storage for OS installs
and stand alone software diagnostic tools for use on older PCs that
don't properly support booting from USB flash memory devices), the
limited storage capacity and writing speeds detract immensely over
that of the utility of hard disk storage whether it's in the form of a
simple external USB drive or a NAS box full of HDDs.

A modern 4TB WD RED drive represents about a thousand DVD-R disks
(and around about 200 Blu-Ray disks), so the costs per GB of optical
storage is somewhat similar but without the convenience of HDD and
with a huge performance penalty (less than 25% the speed at best if
you forgo the verification pass required to assure that the data was
successfully written to the media - in practice, with verified writes,
the time penaly is more like getting a mere 10% of the backup speed of
HDD based storage.

Life's just too short to waste on such 'pre-historic' archival
methods (and space so limited too - I gave up using DVD-R archival
storage after writing some 400 DVD's worth when the cupboard started
getting full).

I decided that I would do just as well using the homebrewed FreeNAS
box (now running NAS4Free) to archive my growing collection of media
files, upgrading the jbod array of disks piecemeal to to keep pace
with my ever increasing storage capacity demands.

I've now got a total storage capacity of 13TB's worth of HDDs in the
NAS box and looking to upgrade the smallest (2TB) drive to another 4TB
WD RED by the end of the year.

I'm looking forward to the larger 6TB units becoming available at a
less than eye watering price before the end of 2015. I've been running
a file server of one sort or another for almost the past 3 decades now
and it's rather sobering to think that it all started with a 300MB
full height ESDI HDD in an NEC Powermate II (8MHz clocked 80286 CPU)
running NW 3.11) connected to a 'CheaperNet' lan.

I've now got some 40,000 times that storage capacity today and I dare
say I'll almost certainly have 100,000 times the original storage
capacity before the end of this decade.

[1] As a matter of interest, I was listening to an MP3'd episode of
the Goon Show whilst I was reading your post which I'd extracted from
a 7GB stereo wav file captured from a 24 hour internet radio broadcast
just over nine years ago.

I'm pretty certain I deleted the original 7GB wav file once I'd
processed it into a 54 episode MP3 collection because I couldn't
afford to tie up so much disk space. It'd be a different story today
now that 7GB is such 'a mere trifle' on a 4TB disk but back then, it
wasn't so trifling. Oh, how things have changed in less than a decade!

The station, afaicr, was called "GoonShow Radio" and had a repetoire
of 54 episodes contained in its daily endlessly looped output. I used
Winamp to capture the stream and send its output to a wav file,
letting it run for just over 24 hours. This proved sufficient to
captue all 54 episodes with an episode or three spare.

I'd previously been listening directly to the audio stream for a few
days before, noticing that they were simply repeating a limited number
of episodes every 24 hours, and realised that I could archive the lot
by leaving WinAmp to run for just over 24 hours. I'm glad I did
because the station dropped out of existence a week or two later.

The point is that the original stream was just 64Kbps mono (a
reasonable match to the AM radio broadcast quality most listeners of
the day would have experienced) which, being MP3 rather than the
crappy MP2 standard of DAB was quite sufficient quality (no bubbling
mud effects so typical of a 64Kbps mono DAB broadcast).

Mind you, a higher bit rate would have been appreciated but this was
just over 9 years ago when bandwidth was at more of a premium. The
source material was almost certainly taken from the original studio
recording tapes which could have justified higher bit rates to emulate
FM radio quality rather than the AM radio quality it was re-broadcast
in.

Be that as it may, I still enjoy listening to these shows despite the
limitations of the low bit rate mono MP3 storage method (24 hours
worth packed into the space of a single data CD!).

I've digitised a portion of my reel to reel tapes and vynil to wav
files which I _have_ retained. The 192Kbps stereo MP3s which I
carefully crafted for 'easy listening' purposes are almost
indistinguishable in quality from the original wavs.

The deficiencies only become obvious when I use the "3D Surround"
options on the PC speakers which uses anti-phase cross mixing to
simulate a wider stereo image otherwise the straight playback of this
material seems to be just fine to my aged ears whenever I bother to
compare the MP3 against the original wave file playback.

If I wanted to create a compressed archive of all this audio
material, I'd choose a lossless format to preserve the original detail
in the wav files regardless of my own hearing abilities. The storage
costs for digital audio, even with flash media, is cheap enough these
days to call into question the value of lossless compression.

Lossless compression eliminates unnecessary redundency making the
task of reconstructing the original from a moderately corrupted
compressed file all the more problematic.

I f you want to add an extra level of robustness against 'bit rot' in
the storage media, an effective way is simply to duplicate or even
triplicate the archive files since the ddrescue application can
recreate a bit perfect copy from such corrupted duplicated backups.
IOW, use two or three times the storage media for each backup and keep
ddrescue on hand to refresh your archives as soon as your annual 'spot
checks' reveal the first signs of 'bit rot'.

All archival methods need some level of maintenance to retain their
integrity over protracted periods of time. Even well proven ink on
paper materials need to be checked from time to time even if it's a
matter of maintenence intervals measured in half centuries.

With modern digital storage, we'd be pushing our luck with 5 year
maintence intervals. The only saving grace being the ease with which
exact duplicates can be created on replacement and novel media.
Optical disk storage lost its 'Novelty Factor' decades ago hence my
regard of CDs and the like as being positively 'pre-historic'.
--
Regards, J B Good