HP DAT 160 SCSI External Tape Drive Q1574A#AC3 プリント

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Q2. How much further can DAT capacities grow? 

The DAT manufacturers’ group roadmap currently shows another two generations of DAT. Some of 

the enabling factors in the roadmap are: 
• 

There is still room for significantly longer tape in the DAT160 media cartridge. 

• 

The bit density on the DAT160 drive is only slightly more than that on the DAT72 drive, so there is 
significant capacity increase available through increasing the bit density on the existing DAT160 

media. We expect this to be one of the enabling steps for generation 7 DAT. 

For example: 

DAT160 DAT72 

150 m 

170 m 

174 Kbpi 

162 Kbpi 

 
The next capacity point for DAT is expected to be 320 GB (@2:1 compression) (see Appendix B—
DAT roadmap).  
Technology steps to bear in mind are:- 
• 

The wider tape used from the DAT160 drive onwards has essentially given us a two-generation 

head start without any leading edge technology developments. 

• 

Improvements in bit density will yield capacity and performance increases. 

• 

Improvements in drum rotation speed and linear density will give the increased throughput.  

• 

Improvements in tape length will give increased capacity. 

Backwards compatibility to the DAT160 drive will be maintained and HP is already working on the 
next step in the DAT story, the DAT320 drive. 

Q3. The DAT160 drive has a much high transfer rate. How was that 
achieved? 

Transfer rate on DAT technology is determined partly by the wrap angle (amount of tape wrapped 

around the rotating helical scan drum) and the speed of rotation of the drum. 
The wrap angle of the DAT160 drive is 180 degrees compared to only 90 degrees for previous 

generation DAT technologies, so the DAT160 drive actually makes more efficient use of tape in 
contact with the head to increase transfer rate. Further generations will increase the drum speed.