"areal density"
*sprays coffee across desk*
SQUARE INCHES?
Somebody owes me a new keyboard!
Earlier this month Toshiba researchers presented a couple of papers concerning bit-patterned media (BPM) and associated head technologies at a Magnetism and Magnetic Materials Intermag conference in Washington DC. They have been working towards an areal density of 5Tbit/sq in for hard disk drives and this was by way of a …
The problem with this is that capacity goes up according to the areal density whilst sequential read speed only goes up according to the linear density (and random read time hardly at all) unless something can be done about increasing spin speed and seek head movement. The potential in those two elements of performance are very limited.
The result is that this 7 x increase in capacity will be accompanied by an increase in toptal time to read/write the entire disk by a factor of about 2.6. You could be looking at something approaching 20 hours to do that so rebuilding a RAID set or the like could be a long, long job.
Yes, but bandwidth has not caught up with storage capacity. If you have a raid-5 with 14TB drives, and one drive crashes - how long time will it take to repair the raid? Assume you insert a new 14TB drive. It may take 1-2 weeks before the raid is repaired. During repair, the raid-5 is vulnerable to another crash, because of increased stress on the other drives. Therefore raid-5 does not cut it anymore. You need raid-6 to allow two discs to falter. Or even 3 discs to falter (raidz3)
I've always thought that for lower performance, where the greatest factor is huge amounts of data storage .. why not use the 5.25inch form factor? Imagine the current areal density with a 5.25 inch platter, or 6 of them!! I could settle for 3600RPM if it means huge amounts of storage.
We still have optical drives that size, and most computers have the bay(s) to install one.
Are there any real obstacles to this idea?
I could see such a large-platter device having power-draw issues. Also, laptops at 2.5" 5400rpm are fairly slow as they stand. Dropping further to 3600rpm and you'll take quite a while to full-copy one... Granted, if all you do is store your DVD/BluRay collection on it, the read-speed won't be such an issue. But for special-purpose use, rather than a "stick one in every computer" mainstream, the price-point might be slightly prohibitive.