hitachi and seagate; 1T and 500G; how many platter(s)?

[gionapm]

hi guys, would you mind to help me to check:

(a) Hitachi 1TB HDS721010CLA332 SATA II/32MB HDD
(b) Hitachi 500GB HDS721050CLA362 SATA II/16MB HDD
(c) Seagate 1TB ST31000528AS SATA II/32MB HDD
(d) Seagate 500GB ST3500418AS SATA II/16MB HDD

questions:
(1) is single platter or 2 platters? I check that hitachi/seagate web site, not show this ?

(2) now 500GB harddisk, used 500gb single platter? 1T = 500gb single platter x 2 ?

(3) for you, how to suggest which one, I remember seagate large problem need update firmware ?

any idea please!

[fzabkar]

(a) HDS721010CLA332

The following HD Tune tests produce maximum sustained read transfer rates of 138 MB/s, 130 MB/s, 132 MB/s. This is what is to be expected of drives with a data density of 500GB per platter, ie 2 platters.

http://lls3kg.blu.livefilestore.com/y1p ... A_Read.png
http://mikanmike.dip.jp/wp-content/uplo ... 721010.png
http://img.kakaku.com/images/Review/000/016/16961_m.jpg

(b) HDS721050CLA362

Similary, the data rates for the HDS721050CLA362 are 138 MB/s and 130 MB/s, suggesting that the drive has a single platter.

http://bbsimg01.kakaku.k-img.com/images ... 6652_m.jpg
http://bbsimg01.kakaku.k-img.com/images ... 6986_m.jpg

(c) & (d)

According to the relevant digit in the model number, the ST310005(2)8AS has 2 platters, and the ST35004(1)8AS has 1.