WD launches 4TB 7200RPM WD RE SATA & SAS hard disks

I just posted the article WD launches 4TB 7200RPM WD RE SATA & SAS hard disks.

These SAS and SATA models feature 5 platters (800 GB per platter), 7200RPM spindle, 32MB cache, 6Gbps dual-port full duplex connectivity and come in capacities of 1TB (SAS only), 2TB, 3TB and 4TB.

Click to read the full article here: [http://www.myce.com/news/wd-launches-4tb-7200rpm-wd-re-sata-sas-hard-disks-64063/](http://www.myce.com/news/wd-launches-4tb-7200rpm-wd-re-sata-sas-hard-disks-64063/)

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Overpriced, even for enerprise storage… by $100 - $150…
Technology wise, VERY late to the 4tb party…

What does the ‘dual-port full duplex’ mean in this case?

I made a correction, as the Dual-port Full Duplex is for the SAS models only and are also SAS-specific features.

SATA is half-duplex, which means that data can only travel in one direction at a time and thus the bandwidth is shared between the input and output. SAS is full-duplex, which allows data to travel in both directions simultaneously, effectively doubling the bandwidth and reducing latency. This is important in a busy server where read and write operations often take place simultaneously.

The Dual-port feature, also specific to SAS drives, gives a redundant path when both ports are used. For example, each port could be connected to a separate controller, which means that if one controller fails, the other controller takes over to prevent downtime.

There is still a theoretical maximum throughput by the reading heads which are still no match for some of the fastest SSD drives.