The Logic Off Topic list

This is a mail from Marvin Humphrey in reply to Dennis Gunn's mail:

Dennis Gunn:

              > Which kind of suggests that Marvin's idea of archiving
to HD is not
              > so farfetched at all doesn't it.

              Wait one cotton-pickin' minute. I did NOT suggest
archiving to HD. It's a
              bad idea, and with each year that passes after the archive
gets put away, it
              becomes a worse idea. I illustrated WHY it was a bad idea,
by showing what
              kinds of massaging become necessary as media ages, and
implying that such
              massaging would be impossible with hard drives.

              Then I went on to argue why digital storage in general is
unstable and
              unforgiving, referencing Shannon and the theory of the
"noisy channel", and
              a remarkable though somewhat technical article that talks
about the need to
              design error correction algorithms after analyzing the
types of noise that
              are likely to afflict a given channel. That's on the OT
list, for those who
              care.

              -- Marvin Humphrey
              Mastering Engineer and Graphic Designer, emeritus
              CD design website - http://marvin.mrtoads.com



--
Joeri Vankeirsbilck
joeri@...

Belway Productions      -     http://www.belway.com
List-admin   Logic-users/SoundD*ver-users/Logic-TDM

>This is a mail from Marvin Humphrey in reply to Dennis Gunn's mail:
>
>Dennis Gunn:
>
>               > Which kind of suggests that Marvin's idea of 
>archiving to HD is not
>               > so farfetched at all doesn't it.
>
>               Wait one cotton-pickin' minute. I did NOT 
>suggestarchiving to HD. It's a
>               bad idea, and with each year that passes after the 
>archivegets put away, it
>               becomes a worse idea. I illustrated WHY it was a bad 
>idea,by showing what
>               kinds of massaging become necessary as media ages, and 
>implying that such
>               massaging would be impossible with hard drives.
>
>               Then I went on to argue why digital storage in general 
>is unstable and
>               unforgiving, referencing Shannon and the theory of the 
>"noisy channel", and
>               a remarkable though somewhat technical article that 
>talks about the need to
>               design error correction algorithms after analyzing the 
>types of noise that
>               are likely to afflict a given channel. That's on the 
>OT list, for those who
>               care.

Yes, after I hit the send button I realized you were just noting that 
some people do it, not endorsing the practice.  Not being to big on 
math I am sure the Shannon article would shoot right over my head.

But, no matter what, since the industry is on a pretty straight 
course in the digital direction, the problem of digital storage is 
going to be something we are all definitely stuck with from here on 
out.  And not just for audio.  So out of curiosity, and leaving 
possible future compatibility issues aside for the moment, do you 
think a disengaged hard drive on a shelf would be more or less stable 
than DVDs or CDRs or for that matter tape as a storage medium?   As 
long as the bearings can last OK on the shelf it seems like a HD 
might more stable than a reel of tape.  It would mainly be a matter 
of how long the bits could keep their magnetic alignment I wouldn't 
it?

Don't get me wrong though  it is purely a neutral or anyway 
conjectural question because personally I have no real idea.


-- 


                                 Dennis Gunn
                                 Mightyjohn@...

                  check out  MIGHTY JOHN HENRY's album "hot air head"
                                                    info at
                        http://www.twics.com/~mightyjo/home.html

Dennis Gunn:

> do you think a disengaged hard drive on a shelf would be more or less stable
> than DVDs or CDRs or for that matter tape as a storage medium?

I'm going optical.

> As long as the bearings can last OK on the shelf it seems like a HD might more
> stable than a reel of tape.  It would mainly be a matter of how long the bits
> could keep their magnetic alignment I wouldn't it?

I am not an expert on the chemical composition of binder that holds the
oxide particles to the hard drive platters.  I imagine that is a critical
issue, as it is with tape.  However, as information density goes up,
longevity goes down, which makes me doubt the long term viability of the HD
format even if you could remove bearings from the equation.

-- Marvin Humphrey
Mastering Engineer and Graphic Designer, emeritus
CD design website - http://marvin.mrtoads.com

At 10:52 PM -0700 7/2/01, Marvin Humphrey wrote:
>Dennis Gunn:
>
>>  do you think a disengaged hard drive on a shelf would be more or less stable
>>  than DVDs or CDRs or for that matter tape as a storage medium?
>
>I'm going optical.
>
>>  As long as the bearings can last OK on the shelf it seems like a 
>>HD might more
>>  stable than a reel of tape.  It would mainly be a matter of how 
>>long the bits
>>  could keep their magnetic alignment I wouldn't it?
>
>I am not an expert on the chemical composition of binder that holds the
>oxide particles to the hard drive platters.  I imagine that is a critical
>issue, as it is with tape.

I don't know either but I think there are two important differences 
worth considering.  1. The drive platters are designed to withstand 
pretty hostile temperatures and are in a sealed container the 
atmosphere of which would probably be easier to keep neutral whereas 
the tapes are not.   2.  The heads of the drives do not actually 
contact the medium the way the heads of a tape machine do so even if 
the binding medium does get a little weak it probably is not as big 
of an issue as with tape since there is nothing trying to rub it off.


>However, as information density goes up,
>longevity goes down, which makes me doubt the long term viability of the HD
>format even if you could remove bearings from the equation.

Definitely true but because a big project will not fit on a CD people 
will eventually start using DVDs to archive instead of CDRs and the 
same dynamic will apply.

I use optical medium for storage as well and will probably continue 
to.   I don't know what is best.   Or what will be.   I have seen CDs 
fail and start leaking ink though.  I have also had DAT tapes go bad. 
And cassettes.  And reals..... The whole issue makes me nervous.

I hope somebody comes up with an answer sometime.  Holograms etched in gold?


-- 


                                 Dennis Gunn
                                 Mightyjohn@...

                  check out  MIGHTY JOHN HENRY's album "hot air head"
                                                    info at
                        http://www.twics.com/~mightyjo/home.html

At 10:52 PM 2/07/01 -0700, Marvin Humphrey wrote:

>I am not an expert on the chemical composition of binder that holds the
>oxide particles to the hard drive platters.  I imagine that is a critical
>issue, as it is with tape.  However, as information density goes up,
>longevity goes down, which makes me doubt the long term viability of the HD
>format even if you could remove bearings from the equation.

Hard drives and plastic tape are completely different kettles of fish. 

Magnetic tape needs oxide particles attached to it because it is not itself
a magnetic medium. All that baking etc that you need to do with old tapes
is to do with the deterioration of the non-magnetic components -- the
binder etc. The surface of a hard-drive platter_ is_ a magnetic medium. It
doesn't need another one glued onto it. The magnetic domains that represent
the information stored on the disc are regions in the metal lattice that
makes up the coating on the hard-drive platter. How well they last I don't
know -- it probably has to do with the properties of magnetism in the metal
used and the size of the domains and what the frequency of cosmic ray
radiation is in the vicinity of the platters etc.

One issue that bears heavily on the suitablity of any digital media for
archiving  is the difficulty of finding a working drive to read them and/or
the necessary interfaces to connect them to a computer. For example -- will
a  ATA drive (parallel) from the year 2000 be connectable to any computer
in the year 2020 without resorting to custom built interface hardware? All
manner of magnetic media -- 8" and 51/4" floppy drives, backup tapes etc
are very hard to use years later for this reason even if the stored
information is not corrupt. There seems some likelihood that CD's will be
readable in backwardly compatible drives for quite some years to come (CDs
are already 20 years old next year) but sooner or later a 5 1/4" medium is
going to look very big and clumsy I suspect. 

Regards,
Murray