What are Common Specs for Hard Disks?

[r_manic]

Similar to what I want to do for CPUs, what do you think is a good set of standard specs by which hard disks can be compared? Here's what I have in mind so far:

Name | Caviar Blue 500GB | FreeAgent Go 1TB
Brand | Western Digital | seagate
Type | Internal | External
Model Number | WD5000AAKS | ST910004FAA2E1-RK

Interface | SATA | USB 2.0
Capacity | 500GB | 1TB
Form Factor | 3.5" | 2.5"(?)
RPM | 7200 | ?
Cache | 16MB | ?

Average Seek Time | 8.9 ms | ?
Average Write Time | 10.9 ms | ?
Average Latency | 4.2 ms | ?

As you can see, for some models the available specs are limited. Nevertheless, do the specs above provide a good point of comparison? Am I missing out anything?

 

[student_sol]

Are you trying to compare between 2.5" vs 3.5" drives, or are you looking for "standard" or representative spec of each size? I think you should include the number of platters/platter density, since number of platters give an easy indication of general performance, power consumption and value-per-money. Too bad WD never clearly states this, and it's not easy to find out what hard drive they're using in those all-in-one drives sold by the manufacturers.

 

[cjl]

Capacity per platter would be nice to have, though it isn't explicitly stated for many models.

 

[geofelt]

The metric that most should be interested in are the maximum and minimum data transfer rates. This will not necessarily corespond to the rotation speed which is commonly assumed. This number can usually be found only on the manufacturer's spec sheet. It is important, because the best data transfer rates are at the faster outer cylinders of the drive, and that is where the OS will be loaded.

You might also want to know the maximum cache to interface rates. With 6gb sata on the way, can the drive utilize it?

Also, how about mean time to failure rates?

 

[r_manic]

@student_sol, I'm actually trying to compare all hard disks in general. Come to think of it though, there should be two categories, "internal hard disks" and "external hard disks", right? Or should I just use "none specified" when building the database?

@cjl, would it be better to try getting the number of platters for each hard disk? Then the visitor could just extrapolate capacity/platter by division, right?

@geofelt, this is usually listed on spec pages as "max data transfer rates" or something similar? And yes, thanks for pointing out interface rates.

 

[cjl]

Capacity per platter is a better metric - if you had that, it would quickly tell you the (rough) sequential performance. Two drives of identical spin speed and platter capacity would have very nearly identical sequential performance, regardless of total capacity.

 

[geofelt]

Why not go to the various drive web sites, and see what they list?

For example here is the performance specification for Western digital Caviar black drives:
http://www.wdc.com/en/products/Products.asp?DriveID=733#jump11

Also, look at the drive specification sheet:
http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-701276.pdf
That is where you will find the maximum sustained data transfer rates.

 

[r_manic]

Awesome geofelt, this is exactly the kind of list I'm looking for! Let's just hope manufacturers make the data available for all their hard disks. Link to database to come once it's complete!