Talk:Perpendicular recording

Implementations section stops at 2009

Have there really been no more advances since 2009? — Preceding unsigned comment added by 2601:2C7:780:4DE2:98D0:C86:AD8B:44CE (talk) 22:31, 14 May 2018 (UTC)

image is wrong

SHOOT the sinebot! SHOOT the sinebot! While I worked to add my signature it auto-signed, created a conflict, and thereby I Lost 15 lines of (additional) editing.

The image is wrong. The most important is that in the new perpendicular recording method the field lines on the left are much further apart because of the large surface area.

In the first "old" recording ring, the ends are tapered, and most fieldlines eminate from there..... -- Rewolff (talk) 15:10, 23 January 2009 (UTC)

I don't know much about svg, but maybe one could change this image: de:Datei:Perpendicular_Recording.svg The picture itself is very good, but the captions are in german. -- JonnyJD (talk) 18:19, 24 January 2009 (UTC)

Encoding

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!

Not true either. As far as I know, there are say 65536 patterns of length 18 patterns of yes-no-transitions that together encode 16 bits. -- Rewolff (talk) 15:05, 23 January 2009 (UTC)

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)

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.

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).

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....

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)

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...

Correct! Speeds jumped from around 50Mb/sec to near 100Mb/sec in a short while after this invention. -- Rewolff (talk) 15:19, 23 January 2009 (UTC)

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)

Needs work on relative vs absolute time

WP:MOSNUM says to avoid words like "current" and "recent", because they become stale with time. It suggests substituting specific years. I fixed one such instance in the first paragraph, but the second paragraph has a number of them that are more difficult to fix without knowledge of the actual timelines. (Also, nobody's come up with a good way to distinguish between the first decade after 2000 and the first century, making a comment along the lines of "in the mid-1990s ..." be problematic; the apparently equivalent "mid-2000s" could refer to 200x or to 20xx.)

Jordan Brown (talk) 19:33, 24 September 2008 (UTC)

Some people suggest nineties and naughties. :-) I would suggest "midway through the first decade of the 21st century". Not quite compact, but usable. Or "around 2005". -- Rewolff (talk) 15:22, 23 January 2009 (UTC)

Last sentence sounds like a commercial

"This represents the biggest jump in hard drive storage capacity in the last 50 years of hard drive technology."

And a most likely untrue one, at that. 1 to 1.5 TB is the exact same 50% as 40 to 60 GB was, no? 70 to 130 *MB*?

I realise 640 GB HD's are now available, but for all intents and purposes the market went straight from 500 to 750 GB, no? --Grndrush (talk) 17:58, 6 October 2008 (UTC)

• 10 MB to 20 MB*  ;) --Grndrush (talk) 18:01, 6 October 2008 (UTC)

• 1 MB to 2 MB? :)

The jump was before that. Maxtor (when it still existed) announced a 320Gb drive available commercially for "next December or maybe only in January". It turned out to be a full year later! I'm afraid I don't remember the year. But shortly after that, perpendicular recording came on the scene, and the almost-a-year of little progress was quickly regained..... -- Rewolff (talk) 15:26, 23 January 2009 (UTC)

Vertically modulated phonograph recordings

The search term "Vertical recordings" redirects here. That term is also commonly used by collectors of antique phonograph recordings which were recorded with a "hill-and-dale" modulation, as opposed to the much more common method of recording sound in the sides of the groove. To that end, I suggest splitting the term "Vertical recordings" into a disambiguation page, one choice going to Phonograph, the other to this page. Typofixer76 (talk) 01:24, 3 April 2011 (UTC)

Definition, lead section

At present the lead section launches straight into talking about perpendicular recording and its uses, advantages and history without ever saying what it is. There's no definition later either. Really the lead section needs one right at the beginning. Based on the the descriptions further on, I suggest something along these lines:

Perpendicular recording is a technique for storing information in a magnetic medium such as the coating of a hard disk. At the point where it is read, the direction of magnetization is perpendicular, rather than parallel, to the surface of the recording medium.

(I've used information rather than digital data to allow for the possibility that the technique has also been tried for analogue recording, and magnetization rather than magnetic field to make it more concrete for the casual reader.)

Musiconeologist (talk) 18:08, 31 August 2021 (UTC)

CMR is not the same as PMR

"Perpendicular recording (or perpendicular magnetic recording, PMR), also known as conventional magnetic recording (CMR),..." <--- This is wrong, or at least misleading.

PMR describes the way that bits are recorded (vertically), whereas CMR and SMR describe the way that tracks are recorded, either side by side (CMR) or overlapping (SMR). Therefore a drive can be both SMR and PMR. 203.59.50.114 (talk) 22:12, 21 July 2022 (UTC)