8-mm Videocassette Drives

As in 4-mm DAT drives, helical-scan technology constitutes the basic recording technique for 8-mm videocassette tape drives. Magnetic read/write heads are mounted on a rotating drum, with an axis of rotation at approximately 5 degrees from the perpendicular. Unlike 4-mm DAT drives, 8-mm drives use a three-head drive configuration (read head, write head, and servo head) around the drum and a separate erase head.

The tape wraps a quarter of the distance around the drum's circumference between the read and write heads, with the servo head situated midway between the two. The drum rotates at 1831 rpm, and the tape moves slowly in the same direction at 11.1 millimeters per second (or 0.44 inch per second).

Of the five 8-mm drives we tested , the Exabyte EXB-8505XL provides the best perf ormance for the price, followed by the IBM 5/10 GB 8-mm. The EXB-8505XL drive ranks tenth in our overall evaluation as a Windows NT backup subsystem among all the tape drives we tested (and second among the 8-mm drives). As a group, the 8-mm drives are outperformed by the DLT drives and the DAT drives based on the C1533A drive mechanism. But they are intermediate in cost and capacity between DLT and DAT drives.

The physical structure of the 8-mm drives differs mainly in their external housing. The only 8-mm drive we attached to a file server was the HSB5.0 from Dynatek Automation Systems; it came with an Adaptec AHA-1540 SCSI controller and an OEM version of Cheyenne Software's ARCserve 5.01. As in all the tape drives, 8-mm drive performance is affected by interface hardware and backup software.

Once again, because our performance testing in the Windows NT environment uses consistent hardware and software, performance results under the Windows NT backup utility manifest differences of the drives themselves. However, if you are purchasing a solution, complete with a hardware interface and backup software, you'll also want to take a look at our overall scores, which incorporate results using the vendor-supplied components.

8-mm Drive Winner

Exabyte holds the patent for manufacturing all 8-mm tape drives, and its EXB-8505XL was our price/performance favorite.

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FEATURES OF 8-MM DRIVES

                                                  Overall
                                Price   Server  Workstation  NT
Exabyte EXB-8505XL        $2800-$4500   N/A     6.72         7.57
Dynatek HSB5.0                  $2830   8.15    N/A          7.23
IBM 5/10 GB 8-mm                $4005   N/A     6.74         7.56
Storage Dimensions TD1-10000    $3950   N/A     7.07         6.70
TTI CTS-8510H (XL)              $3995   N/A     7.43         7.28

                                        Performance
                                Server  Workstation  NT
Exabyt
e EXB-8505XL              N/A     6.18         7.32
Dynatek HSB5.0                  8.02    N/A          6.80
IBM 5/10 GB 8-mm                N/A     6.22         7.30
Storage Dimensions TD1-10000    N/A     6.62         6.12
TTI CTS-8510H (XL)              N/A     7.14         6.94

                                Features        Usability
Exabyte EXB-8505XL              ****            ***
Dynatek HSB5.0                  ****            ***
IBM 5/10 GB 8-mm                ****            ***
Storage Dimensions TD1-10000    ****            ***
TTI CTS-8510H (XL)              ****            ***

(All 8-mm drives use Exabyte's EXB 8505 drive mechanism.)

Key:
Excellent ****
Good      ***
Fair      **
Poor      *

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8-mm Videocassette Drives

photo_link (48 Kbytes)

Clockwise from the left: Storage Dimensions' TD1-10000, the IBM 5/10 GB 8-mm, the Dynatek Automation Systems HSB5.0, TTI's CTS-8510H (XL), and Exabyte's EXB-8505XL.