Sign in to follow this  
RealtorJ

When do we get a review of the Fujitsu MAS series?

Recommended Posts

If it were the same diameter as the Seagate, perhaps it would sacrifice a bit of capacity on the outer tracks... but that's why Fujitsu went with a larger platter!

Share this post


Link to post
Share on other sites
This is the Fujitsu MAS. Larger platters = a higher top speed due to more spt in the outer "ring", and a unique track configuration that allows it to maintain its speed over a large region of the platter.

OK, so I understand how the track configuration allows the drive to maintain a high STR through 40% of the drive, but what does it give up to accomplish this? Capacity?

MaxtorSCSI pointed out some possible drawbacks....

Share this post


Link to post
Share on other sites

Additional cost would be another potential negative for using slightly larger media. It seems like 65 mm disks would be more common, and media manufacturers will charge more for "non-standard" sizes, or it might reduce your possible supplier pool. Maybe it's not an issue for SCSI drives, though.

Share this post


Link to post
Share on other sites

First off, I thought this conceptual picture from the reference section might help:

z_zbr.jpg

It's simple: Fujitsu uses a larger platter and is therefore able to pack more sectors per track onto its outer tracks. And since Fujitsu is able to maintain this higher spt count over 40% of the tracks, it not only starts out with more spt, but it is able to maintain it over a larger percentage of its capacity.

My only complaint here is that we can only assume that the 5mm difference in media, and hence 2.5mm radius, is fully utiliseable...as I stated earlier, who knows if the unuseable areas of the radius (the portions lost to the spindle [the big hole and surrounding silver area in the picture] and the very outer edge region of the platter [outer brown ring in picture]) are constant between the 65mm vs 70mm drives - this is what I was hoping MaxtorSCSI could have addressed.

But lets proceed as if it is. In fact, for agument's sake, less pretend that the full 35mm radius is used.

Then, given that the Fujitsui has 27094 tracks, we would end up with a track width of ~1.3um.

Which means that the actual extra 2.5mm itself contains ~1936 tracks....which is only 7.1% of the total tracks.

Further, Eugene kindly provided us with the break down of each zone's track composition, and hence we find that these 1936 "extra tracks" work out to be 17.5% of the first zone's total number.

Given that 82.5% of the first zone is composed of what is left after the additional 2.5mm radius is given up, I think it is fair to say that the extra media width did not have a substantial impact on Fujitsui's ability to pack more sectors into the outer tracks....the real accomplishment here is that Fujitsui actually did increase the linear or recording density on its own accord (that is, regardless of the size of the media, they packed more sectors in). Whats even more impressive is that they kept the inner zonal sector/track numbers so high...meaning that the inner zones are incredibly (linearly) dense, and hence why we see such a outstanding ending STR for the MAS.

I don't see how Fujitsu's choice to use slightly larger platters has any affect on its STR performance when taken in conjunction with this statement from Eugene: "In the meantime, same number of data blocks, 705, is allocated in one track about 40% of total cylinders from most outer."

Don't worry, you didn't miss a thing.

CK

Share this post


Link to post
Share on other sites
the real accomplishment here is that Fujitsui actually did increase the linear or recording density on its own accord (that is, regardless of the size of the media, they packed more sectors in).  Whats even more impressive is that they kept the inner zonal sector/track numbers so high...meaning that the inner zones are incredibly (linearly) dense, and hence why we see such a outstanding ending STR for the MAS.

Good point. This seems to have not been given its due, given the fuss about the larger platters.

Share this post


Link to post
Share on other sites

The MAS3735 does not really seem to be "in the channel" as such yet. I bet most of the production is going to Sun, Dell, IBM, et al. I tried to order 9 MAS3735 from newegg.com, but they would only allow me to have 2. Big-name distributors like CDW do not have them at all yet.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this