DLT, ValueDLT and SDLT tape formats

This Techworld document tabulates details of the Value DLT and SuperDLT tape formats and includes road map details where available. These are entry-level and mid-range tape market products from Quantum. DLT
Quantum initiated its Digital Linear Tape (DLT) series of products with DLT-2000, now defunct. DLT proved very popular as it developed and became a mid-range leader, displacing Mammoth in the process. Tracks are wtitten is a serpentine way parallel to the edge of the tape. The media is a half-inch wide. The new Value DLT line replaces the relatively recent DLT formats which are listed here for reference:-

	DLT-4000	DLT-7000	DLT-8000
Raw Capacity	20GB	35GB	40GB
Compressed Capacity	40GB	70GB	80GB
Raw Transfer Rate	1.5MB/sec	5MB/sec	6MB/sec
Compressed Transfer Rate	3MB/sec	10MB/sec	12MB/sec
Date available		1998	1999

The main technical difference between DLT7000 and DLT 8000 was the addition of a Ferrite head. All three formats use the same DLTtapeIV media. In 2001 Quantum introduced its higher capacity SuperDLT drive. Over the next couple of years there was a re-positioning and development of the DLT line into a ValueDLT line which we cover next. ValueDLT

	VS80	VS160	VS320	VS600
Raw Capacity	40GB	80GB	160GB	300GB
Compressed Capacity	800GB	160GB	320GB	600GB
Raw Transfer Rate	3MB/sec	8M/sec	15MB/sec	30MB/sec
Compressed Transfer Rate	6MB/sec	16MB/sec	30MB/sec	60MB/sec

Point your browser here for a DLT roadmap. DLT VS80 and VS160 are available now. Expect VS320 in 2004 and VS600 in or around 2006. The VS80 format uses the DLTtapeIV media and is backward read-compatible with the DLT-4000 format. VS160 is backward read-compatible with VS80. VS320 will be backward read-compatible with VS160. SuperDLT
This is Quantum's super tape offering, the one that directly competes with the various LTO Ultrium formats. Once again it is a half inch linear tape format, like the original DLT and VS-nnn formats. There are five generations on the roadmap.

	SDLT220	SDLT320	SDLT600	SDLT1200	SDLT2400
Raw Capacity	110GB	160GB	300GB	600GB	1.2TB
Compressed Capacity	220GB	320GB	600GB	1.2TB	2.4TB
Raw Transfer Rate	11MB/sec	16M/sec	c32MB/sec	40-80MB/sec	c100MB/sec
Compressed Transfer Rate	22MB/sec	32MB/sec	c64MB/sec	80-160MB/sec	c200MB/sec

The availability dates are: SDLT220 - 2001; SDLT320 - 2002; SDLT600 - 2003; SDLT1200 - 2004; SDLT2400 - c2006. SDLT220 and 320 use SuperDLT 1 tape media whereas SDLT600 uses a new SDLT media. SDLT220 is no longer listed as a current format on the Quantum DLT web site. VS320 overlaps it in capacity. SDLT 320 is backward-read and -write compatible with SDLT220, and backward-read compatible with DLT8000, DLT7000, DLT4000 and DLT VS80 using DLTtapeIV media. SDLT 600 is now available and is backward-read compatible with SDLT 320, SDLT 220 and DLT VS160 drives. SDLT1200 and 2400 planned interfaces include Serial Attach SCSI (SAS), Ultra 320 SCSI and Fibre Channel. SDLT1200 performance is expected to be greater than 50 MB/sec native and 100 MB/sec compressed. SDLT 2400 performance is expected to be greater than 100 MB/sec native and 200 MB/sec compressed. The next articles in this tape format series will look at the proprietary StorageTek and IBM formats.