DVD vs Hard Drive

[Jim Andrada]

Well Erik, there are a lot of differences between tape and disk. In the case of disk, the data is permanently associated with the disk drive. If you can't attach the drive to your system you can't read the data.

In the case of LTO at least, your cartridge is readable in a newer drive and you can be pretty confident of being able to retrieve the data for at least 20 years or more.

By the way, if you have a LOT of data, how about one of these??

Big Blue tapes up big data ? Channel Register

[Frans Meijer]

Looks a bit out-of-budget, that IBM monster

I don't think you can expect to archive on any media, stuff it in a safe place and find it to be still readable ten, twenty years from now. Apart from having multiple copies, you'll likely have to refresh the archives regularly and connections, interfaces and protocols disappearing are not going to be an issue when you refresh your archives timely.

Refreshing an archive stored on harddisk costs about ten seconds of your time (never mind that your system will sweat on it for hours, or even days). I don't think any other medium can match that.

[Erik Norgaard]

Originally Posted by Jim Snow

There is a big difference between an outdated file format and unreadable data. If a video file can be read, it can be converted to a format that can be read / played.

Add to that: As patents expire, ancient formats can be supported for free. Even if mpeg2 will eventually be replaced by mpeg4 or something completely different, I believe it will be supported simply because it doesn't cost extra.

[Erik Norgaard]

Originally Posted by Jim Andrada

In the case of LTO at least, your cartridge is readable in a newer drive and you can be pretty confident of being able to retrieve the data for at least 20 years or more.

I think it's not a good idea to plan for any media to last more than 5 years, 10 if you're lucky. Backward compatibility is a nice feature, but it also hold back advances in technology, I wouldn't expect it. In stead, I believe the continuous migration to newer media is a safer bet. Simply taking the past into the future. This works as long as storage capacity (as in GB/$) grows faster than my storage needs.

Say, this year I need 1TB and I'll get a 1TB drive, next year I need another 1TB, but as storage capacity grows exponentially, by that time, I'll get a 2TB drive for the cost of a 1TB drive today. Even if capacity doesn't double every year, it's good enough because it does grow exponentially while my needs grow linearly, as long as new formats doesn't enter the market, say as SD->HD or HD->4K. So, following this strategy, possibly I won't be able to read a five year old drive because of changes to the interfaces, but frankly I don't care, because the same data is on my 4, 3, 2 and 1 year old drives.

Just to compare HDD capacity against LTO: LTO has gone from 100GB in 2001 to 1.5TB in 2010, that's 15 times the initial, but HDD has a history of 100 fold capacity growth per decade. So, eventually tape just doesn't make sense in the GB/$ race even for long term archival, it becomes cheaper to copy data to newer disks than to invest in tapes. For what I can see, break even is just about now.

BR, Erik

[Jim Andrada]

I've heard around that we may actually start to see price increases in computer stuff in the next year or so. Partly due to higher labor cost in China and shortages of supply due to the Japan earthquake. Chinese labor cost has risen very significantly in the last year or two. Some Chinese companies are actually outsourcing manufacturing to Vietnam.

The typical analysis of total cost of tape vs disk assumes that the disks are running and sucking electricity and that tape cartridges are sitting quietly on a shelf or more often in a robotic library of some sort.

The reasoning is simple. Disks are engineered to spin, not to sit around for long periods of time. Tape cartridges are engineered to sit around. We have decades of experience in engineering both types of media. Some disk arrays support what is called MAID - ie massive Array of Inactive Disk - the arrays can power drives down either completely or to slow spin status depending on usage, This feature has been moderately well accepted in Japan but not in the US or Europe.

I don't know of any major disk user (except individuals or really small outfits) who store disk drives on the shelf. There is a technology called RDX (RDX Removable Disk Storage Solutions & Backup Technology | RDX) that is trying to gain traction - it consists of drives with removable disk cartridges similar to tape cartridges,

[Brian Drysdale]

I heard a story - don't know if it's an urban myth - that one NY ad agency went back to film for stills photography because of the cost of archiving the digital data was so high.

[Jim Andrada]

Could be - on the other hand, the cost of medium format digital backs is in the $30k each range so that might have something to do with it - as well as the 500mb images.

Although the cost of film and processing can be pretty astronomical these days as well

[Vincent Oliver]

Most technology takes three or more steps forward and one step backwards. Look at the Vynl LP crowd, convincing themselves that Vynl disks are the ultimate in sound quality - so good you can hear every click, crackle and pop. Film is also great, I liked the convenience of having several cups of coffee whilst waiting for film to be processed.

As for storage, I can see the point of a NY agency wanting some method that is cheaper to store images, at least you can see where the filing cabinet is in a room. I'm all for it, bring back the good old days, dust and fingerprints on film and all.

[Jim Andrada]

I forgot all about the fingerprints. Sometimes they were the most interesting part

[Brian Drysdale]

Originally Posted by Vincent Oliver

Look at the Vynl LP crowd, convincing themselves that Vynl disks are the ultimate in sound quality - so good you can hear every click, crackle and pop.

Although, from an archive viewpoint they'd last pretty well, just keep them away from the radiator.

[Vincent Oliver]

Yes, LP's would last well, but were susceptible to damage, which in turn could destroy a track or entire album. Go to your local music store and see if you can get a replacement stylus!. Audio tape (cassettes) were also prone to stretching and oxide deterioration - can't remember how often I had to clean and de-magnetise the heads.

I guess the bottom line is that no media is without its faults, I just wish some Association of film makers would agree on a standardised media storage that could be future proof, i.e. tomorrows hardware should still be able to read today's data. I know things will progress in terms of speed and capacity. Hopefully it will be some form of Solid State memory.

[Brian Drysdale]

Although a stylus is easy to manufacture compared to other systems.

Voyager - The Interstellar Mission

[Vincent Oliver]

Interesting item on Voyager, I have seen this before. Supposing this craft landed on a similar planet to earth and a Chimp found it.

The mind boggles at the thought of what if?

ps. I sold my collection of LP's a few years back, but I still have a very large collection of 78rpm disks and a wind up player which still works. The George Formbie disks are great fun as are many of the trad jazz disks. The only problem is that you can only drop the disks once.

[Sareesh Sudhakaran]

Anybody know anything about holographic storage?

[Stelios Christofides]

This is interesting:

Optical media longevity


stelios