X-bit labs

WD740GD aka Raptor 2 Hard Disk Drive Review (page 2)

Category: Storage

by Nikita Nikolaichev

[ 02/18/2004 | 11:37 PM ]

The new HDD features 74GB storage capacity, which is twice as large as the old Raptor drive had. This storage capacity was achieved due to the use of two platters instead of one. We even weighed the drives to make sure that our suppositions are correct:

  
WD360GD on the left and WD740GD on the right

As you see, the first HDD is a little bit heavier. Just one platter heavier… You can also clearly see from the photo below that WD740GD really does have two platters:

However, the differences between the new WD740GD and the old WD360GD are much more significant than just a different number of platters. The new Raptor features platters with higher bit density and hence boasts higher read speed from the platter. The track seek time also reduced to 4.5msec against 5.2msec by the old WD360GD. The 0.7msec seek time improvement is a tremendous technological breakthrough, which puts WD740DG onto one level with the most advanced SCSI HDDs with 10,000rpm spindle rotation speed.

The new Raptor also boasts one very interesting technology aka Rotary Accelerometer Feed Forward (RAFF). The idea behind this technology implies that the HDD watches the case vibrations generated during the read/write heads repositioning. This is done with the help of special accelerometers (sensors measuring the acceleration speed). Special algorithms calculate the heads trajectory so that it takes them the minimal amount of time to find the desired track without any delays. The same technology also works during linear reading: the HDD controller keeps the head on a track responding to the case vibrations with the preliminarily calculated actuator movements.

One more interesting technology from WD, which is not directly connected with Raptor drives, but which is worth mentioning here In the very first article devoted to a SerialATA hard disk drive called Seagate Barracuda Serial ATA V Hard Disk Drive Review I mentioned that the SATA cable is not locked tightly enough in the corresponding connector of the drive. If the cable hanged loosely or was slightly pushed aside, then the plug jumped off the connector and… I believe you can imagine what happened next. What a great data losses could happen if the connection between the HDD and the controller would break during the data transfer! I am afraid even to think of it, not to mention going through it on my own…

Only if the HDD and cable connectors get bigger the contact could get somewhat more secure. And if this is not possible, then all we have to do is to increase the contact area around the connector. This exactly what WD engineers did in their new Raptor drives. The new solution is called SecureConnect!

The new SecureConnect cable looks as follows:

And this is what the HDD connector look like:

The red arrows mark special holes in the HDD case where the connector hooks should go once you plug the cable in. Note that the holes are equipped with special metal pads from the inside for higher contact security.

Due to two “rails” and large contact surface of the new plug, the connection is highly secure, which is exactly what the new SecureConnect has been aimed at. I wish I had more than two cables like that…

And now let’s pass over to the discussion of one very interesting and mysterious feature of the new WD740GD drive.