Register FAQ / Rules Forum Spy Search Today's Posts Mark Forums Read
Go Back   MacRumors Forums > Apple Hardware > Desktops > Mac Pro

Reply
 
Thread Tools Search this Thread Display Modes
Old Feb 25, 2013, 08:16 AM   #51
Tesselator
macrumors 601
 
Tesselator's Avatar
 
Join Date: Jan 2008
Location: Japan
Quote:
Originally Posted by nigelbb View Post
Magnetic tape does not suffer damage from cosmic rays. That idea is utter tosh. Cosmic rays are charged particles they don't interfere with magnetic particles on tapes. Computer memory may rarely be altered by cosmic rays which is one reason why servers use ECC memory. In the old days of reel to reel tape it was good practice every year or 2 that the tape was de-spooled & re-spooled to prevent data 'burning through' but better design of more recent cartridge tapes means this is no longer necessary.
That's funny. If you studied a little you would know there is just about nothing on this planet that isn't damaged by cosmic rays and BG radiation - including you and I, but also hardened steel, glass, ceramics, chrome, plastics of all kinds. Really, everything!

So it's kinda silly to suggest that magnetic tapes are unaffected. LOL Now consider their construction... Spooled in a tight spiral. When a ray hits it, it doesn't just damage one area on a flat surface like disks are formed as... no, it may go through hundreds of layers and cause a whole bunch of information loss with just one strike.

You can do a search and find out how many millions of ray events are striking the Earth every second if you'd like. From there it's only a few simple equations to determine the chance over time that something the size of one of those tape spools gets hit - and how many times per period, etc.

Remember the Ultrium 5 and 6 tapes now have a data density 15,140+ bits/mm and the 1980's tapes you're referring to were 800 or 1600 CPI. That's about 566 bits/mm in the later case - half that for the 800's. The industry stopped updating the standards of those systems at about 2200 bits/mm and those were 9-track tapes with a parity track. You can also research the relationship between data density and cosmic ray damage quite easily - the studies are numerous and prevailing.

I know you want to defend tape but we have to be honest about things too.

Last edited by Tesselator; Feb 25, 2013 at 08:51 AM.
Tesselator is offline   0 Reply With Quote
Old Feb 25, 2013, 09:21 AM   #52
nigelbb
macrumors regular
 
Join Date: Dec 2012
I wasn't suggesting that magnetic tape doesn't get hit by cosmic rays just refuting the nonsense that
Quote:
Tape is particularly vulnerable to background radiation and cosmic rays.
It's not. Data tapes have an archival life of at least 30 years without any special storage requirements other than normal humidity & temperature.
nigelbb is offline   0 Reply With Quote
Old Feb 25, 2013, 09:29 AM   #53
Tesselator
macrumors 601
 
Tesselator's Avatar
 
Join Date: Jan 2008
Location: Japan
Quote:
Originally Posted by nigelbb View Post
I wasn't suggesting that magnetic tape doesn't get hit by cosmic rays just refuting the nonsense that It's not. Data tapes have an archival life of at least 30 years without any special storage requirements other than normal humidity & temperature.
Well, I just explained why in fact it actually is so in my previous post. There's not a thinking scientist on the planet who would argue the point. It's of course up to you weather to buy into the distributed marketing sheets or trust common sense and science. <shrug>

My reaction:

30 Years: ROFLMAO! (and that's the 1st time I've ever used that acronym!)
10 Years: Unlikely!
5 Years: If you're lucky - sure.
3 Years: Probably, yes.

Last edited by Tesselator; Feb 25, 2013 at 09:38 AM.
Tesselator is offline   0 Reply With Quote
Old Feb 25, 2013, 11:19 AM   #54
nigelbb
macrumors regular
 
Join Date: Dec 2012
Care to provide some evidence or even a reference to support the statement that "Tape is particularly vulnerable to background radiation and cosmic rays"?
nigelbb is offline   0 Reply With Quote
Old Feb 25, 2013, 02:36 PM   #55
d-m-a-x
macrumors 6502
 
Join Date: Aug 2011
Quote:
Originally Posted by nigelbb View Post
Care to provide some evidence or even a reference to support the statement that "Tape is particularly vulnerable to background radiation and cosmic rays"?
Go to a thrift store and buy a 30 year old Indiana Jones Vhs tape and see how it looks compared to a tape from 2002 - the tech is the same, the difference is staggering
d-m-a-x is offline   0 Reply With Quote
Old Feb 25, 2013, 11:31 PM   #56
brentsg
macrumors 68020
 
brentsg's Avatar
 
Join Date: Oct 2008
Quote:
Originally Posted by d-m-a-x View Post
Go to a thrift store and buy a 30 year old Indiana Jones Vhs tape and see how it looks compared to a tape from 2002 - the tech is the same, the difference is staggering
That VHS tape from 25+ years ago was quite likely used and abused if it wasn't a rental in a previous life. I wouldn't call that a proper comparison.
brentsg is offline   0 Reply With Quote
Old Feb 25, 2013, 11:44 PM   #57
d-m-a-x
macrumors 6502
 
Join Date: Aug 2011
Quote:
Originally Posted by brentsg View Post
That VHS tape from 25+ years ago was quite likely used and abused if it wasn't a rental in a previous life. I wouldn't call that a proper comparison.
i see the same thing in old unexposed motion picture film that has been sitting for a long time. The upper part of the frame is partially exposed and has extra noise.

probably why the edges of the optical discs go first when stored verticaly

Last edited by d-m-a-x; Feb 25, 2013 at 11:59 PM.
d-m-a-x is offline   0 Reply With Quote
Old Feb 27, 2013, 05:10 AM   #58
nigelbb
macrumors regular
 
Join Date: Dec 2012
Quote:
Originally Posted by nigelbb View Post
Care to provide some evidence or even a reference to support the statement that "Tape is particularly vulnerable to background radiation and cosmic rays"?
Quote:
Originally Posted by d-m-a-x View Post
Go to a thrift store and buy a 30 year old Indiana Jones Vhs tape and see how it looks compared to a tape from 2002 - the tech is the same, the difference is staggering
That is no proof of damage by cosmic rays or indeed proof of anything else. I had a good look around & can find not a single reference to tapes being damaged by background radiation and cosmic rays even less that tape is particularly vulnerable. You statement is simply not true.
nigelbb is offline   0 Reply With Quote
Old Feb 27, 2013, 07:15 AM   #59
Tesselator
macrumors 601
 
Tesselator's Avatar
 
Join Date: Jan 2008
Location: Japan
Yeah, LOL we've come to a really strange place here:
It's not on the internet so it's not true!

I couldn't find a link so it doesn't exist!
Did everyone laugh their butts off when they read that or just me?
Tesselator is offline   0 Reply With Quote
Old Feb 27, 2013, 07:51 AM   #60
nigelbb
macrumors regular
 
Join Date: Dec 2012
Just you I am afraid as given the impossibility of proving a negative the onus is on those who claim that "Tape is particularly vulnerable to background radiation and cosmic rays" to either offer some proof for this statement or S.T.F.U..

Tape & magneto-optical discs are the archival media of choice for computer data because the integrity can be guaranteed for decades. This is of course not very impressive compared to other storage media that can store data for hundreds of years e.g. paper.
nigelbb is offline   0 Reply With Quote

Reply
MacRumors Forums > Apple Hardware > Desktops > Mac Pro

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -5. The time now is 05:57 PM.

Mac Rumors | Mac | iPhone | iPhone Game Reviews | iPhone Apps

Mobile Version | Fixed | Fluid | Fluid HD
Copyright 2002-2013, MacRumors.com, LLC