Talk:Perpendicular recording

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Very subtle troll going on here, wouldn't have noticed it if Timecop didn't post. Hint: Down is 1, Up is 0.

Sorry, wrong --- One = magnetic transition (i.e. a change from up to down or vice versa), zero = no transition!

Contents

[edit] 250 Gbit/sq

Being the meter the SI unit, can anyone edit this article to display SI units? --Mecanismo 18:32, 19 August 2005 (UTC)

[edit] upper limit of superparamagnetic effect

I am no expert, but I think the number 'max 250 Gbit/sq. inch' due to the the superparamagnetic limit is wrong. This is the number quoted by hitachi for the estimated density of their NEW perpendicular recording media, NOT the old longitudinal one.

Although I do not have time to look it up carefully right now, I have read that the limit is more like 100 Gbit/in^2. Perpendicular recording will bring this up to 500 Gbit/in^2.

Please see www.ieeemagnetics.org/Newsletter/05october/Oct2005_Newsletter.pdf and seach keywords. They suggest that the superparamagnetic limit is somewhere between 100 and 200 Gbit/in^2. (this number is constantly changing)

Also, Gbit/in^2 is the industry standard unit.

Again, I have only vague knowledge of all this, please double-check.

[edit] The super-paramagnetic limit

is a 'soft limit', or an engineering limit. It arises from material properties and recording technology employed. Perpendicular recording allows to extend this limit to the quoted ~500 Gb/in^2 due to the fact that harder (higher coercivity) magnetic media can be used, since the perpendicular geometry allows to use the head's write field about 2x or so more efficiently. This then allows to scale the size of the recorded bit (while remaining thermally stable).

[edit] Merge

Perpendicular Magnetic Recording duplicates info as presented on this page. Also, that page is far less mature than this. It should be merged here. --Soumyasch 07:55, 25 March 2006 (UTC)

Seconded. It's a duplicate article. Fdgfds 01:58, 8 April 2006 (UTC)

This seems to be taken care of....

[edit] Toshiba reliability issues

Any citation or example of the "reliability issues" suffered by Toshiba PMR drives? Are such issues unique to Toshiba drives? Nllewellyn 20:35, 8 December 2006 (UTC)

[edit] Speed impact

Does anyone know anything about the impact on speed? Theoretically, the data tightness ought to give a higher data output at the same RPMs as longitudinal drives...

== Quote from InfoStor does not violate copyright laws. http://www.infostor.com/display_article/245676/23/ARCHI/none/none/1/Seagate-goes-perpendicular/ The quote from that article was written by the Web editor of that magazine. —Preceding unsigned comment added by ATD-Storage (talk • contribs) 18:10, 15 January 2008 (UTC)