HP DAT 160 SCSI External Tape Drive Q1574A#AC3 Leaflet

Q4. The backwards compatibility with the HP StorageWorks DAT72 
and DAT40 tape drives is really important to customers. Can you 
explain how this works? 

The ability of the DAT160 drive to write and read DAT72 and DAT40 media has been a challenge, 

but the pre-design simulations showed it was possible with margin to spare. The HP approach of 

using independent tape threading mechanisms was the breakthrough that enabled this part of the 

design to become a reality. 
An explanation of the threading/tape loading process is shown in Figure 7. 
• 

Separate guides are used to load DAT160 media or DAT72/DAT40 media, shown in brown for 

DAT160 and blue for DAT72/DAT40.  

• 

Only one guide, shown in yellow, is common. This allows more control to accurately position the 
tape around the drum than a design that shares many guides.  

• 

Guides can be set and adjusted for optimum performance with each tape format. 

 

Figure 6. DAT160 drive maintaining interchange—the same drum is used for both 4-mm and 8-mm tapes  

 
At first sight, the ability for any tape drive to accommodate two different tape widths looks daunting, 

if not difficult. However, the ability for the DAT160 drive to read and write to earlier DAT72 and 

DAT40 media was always a project “must.” As a consequence, the drive was designed from the 
outset with the needs of two different tape types in mind. 

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