HDD bytes per sector types; 521e vs 512n vs 4Kn?

[videobruce]

I'm in the market for a replacement HDD; 4TB vs 2TB. I settled for Seagate Enterprise. The 3 models are the same price & same warranty $150 5yrs,

The types are
521e (emulated),
512n (native) and
4Kn 4096 native

I have many a few good articles on the differences sine this aspect never came up before, 20 years playing around with computers. I only looked at manufacture, capacity, interface, speed, & warranty.

I'm running Win7 Pro (still), I may go to W10, but that is a maybe. The drives I have currently are one SSD and two Hitachi 2TB with a 512 BPS spec. I looked up the specs and all that is provided is "512", not 512e or 512n. So I don't know what they are. The drives models numbers are identical except for the last digit; 0 vs 1;
Hitachi HUA723020ALA640

From what I have read, 521e is the way to go for current compatibility. But, that seems debatable according to the articles. This replacement will be a 'storage' drive and it seemed that a 4096 BPS would be the better choice.

Input please.

[videobruce]

The Seagate Enterprise choices are;
ST4000NM0115
ST4000NM0085
ST4000NM0035

[DanceswithUnix]

This replacement will be a 'storage' drive and it seemed that a 4096 BPS would be the better choice.

Sounds like the way to go. It is the new standard, so unless you are wanting to run the drive under something like Windows XP just get the standard 4K drive.

I'm guessing 521e is a typo and should be 512e meaning the sectors are actually 4K but the drive can pretend it has smaller 512B sectors by doing a read of the rest of the 4KiB sector, mixing in your 512 byte chunk and then writing it back with a potential awful performance. I have never heard of a 521 byte sector so can't imagine why you would want to emulate one

[matts-uk]

I'm running Win7 Pro (still), I may go to W10...

The storage industry has agreed to migrate to a 4K bytes per sector low level format, so called AFD, to increase data-density and i/o efficiencies.

At the physical layer:

• Each sector comprises an index mark, a gap and ECC information overheads in addition to the data bytes. Increasing the bytes per sector reduces the number of sectors and the physical space occupied by the overheads.
• Reducing the space occupied by overheads reduces the r/w head 'null time' overall, as the head spends less time on average moving over areas of the platter that do not contain data.

The (old) 512 bytes per sector format is a particular issue in large scale data-centres where a money value can be attributed to any 'wasted' space.

• 512n is the traditional format.
• 512e is a stepping stone to accommodate legacy applications. The platter uses a 4K physical sector and the drive electronics translates to a 512 logical sector. The translation reduces write efficiency as logical sector changes have to be merged into the physical sector in the drive's DRAM before being written to the physical disk; but you are unlikely to notice with a couple disks in a PC.
• 4Kn is the migration end point but is not compatible with some legacy O/S and enterprise applications.
• 512n, 512e, 4Kn should not be mixed in an array.

Windows 7 is not entirely compatible with 4Kn. SP1 (or the relevant KB update) must be applied. Some BIOS versions may refuse to boot. Some RAID drivers may refuse to work at all.