Tape Roundup For The Server Market.

The server market--SOHO, entry-level servers, and workstations-over-whelmingly use magnetic tape for their storage needs, since there is nothing else out there that combines low prices, storage capacity, and ease of use.

DDS-4, DAT's Poster Child

DDS (Digital Data Storage) is the industry standard, the survivor of the format wars of the early '90s and the market leader in unit shipments at a 45% share. DDS-4, its latest generation, is a 4mm helical scan drive manufactured by several different companies, including Sony, HP, and Seagate. With a 20GB native capacity and a 3MB/sec uncompressed transfer speed, it utilizes a high coercivity metal particle tape for high recording density and efficient encoding schemes.

DDS-4's major advantages include compatibility with a large installed base of almost nine million DDS drives, multiple drive suppliers, and reliability based on improved head cleaning, TapeAlert, real-time adaptive filtering, and Advanced Sequence Detection. Its popularity has generated a number of automation products, including automated changers that can back up more than 100GB of data.

It does have its disadvantages. Among them are strong competition from tape products such as Ecrix VXA, Tandberg SLR, and Travan SCSI mini-cartridges, as well as concern about the viability of its next-generation, high capacity version DDS-5. Thus far, Sony and Seagate seem to have bowed out of further DDS development, leaving Hewlett Packard as the only major player. Since DDS is so widely installed and supported, the lack of a DDS-5 path may not be a major issue now, but it will become one if the migration path hits a dead end.

Travan And The Sixth Generation

Travan, a mini-cartridge technology, offers TR-5 and the NS (Network Server) series. Their Network Server series is targeted to the server market with the most recent NS-20 emphasizing data integrity over speed. With its native capacity of 10GB and an uncompressed transfer speed of 1MB/sec, it features read-while-write data recording and hardware data compression.

Although Travan is suffering from competition, (it's down to 41% of unit deliveries from a 1996 high of 65%) major manufacturers are committed to Travan, including Overland Data, Seagate, Imation, and Tandberg. Interest has lately heated up because of Overland Data's development of the [VR.sup.2] chip, which can double the capacity of presently manufactured drives without any changes in tape path design, recording heads and/or media. Other developments include the recent availability of autoloaders and libraries for Travan media, which it has historically lacked. These twin developments may rescue Travan from losing market share and renew it in the marketplace as a viable tape product for entry-level servers and workstations. Travan has a migration path, but the gap between the TR and NS series is closing, not widening.

SLR Doubles Capacity With [VR.sup.2]

The SLR data cartridge refers to Scalable Linear Recording and sports a thin Film Magneto Resistive Head (TF/MR). SLR-100 incorporates Overland Data's [VR.sup.2] technology (a past winner of CTR's Editor'S Choice) and offers 50GB native capacity and 5MB/sec uncompressed transfer speed. Extremely reliable, it maintains backward compatibility with a huge installed base of QIC drives. The [VR.sup.2] chip technology allowed it to increase its transfer rate by 150% and double its capacity over previous SLR models. Like its predecessors it targets the server market, but it is also heading into the midrange markets. It is not an outright competitor to DLT, but it is largely used on such computers as heavyweight departmental servers.

Another recently shipped product is the SLR-60, which is 30GB native and 4MB/sec. It is priced comparably to DDS-4 and is in direct competition with it.

The SLR's disadvantages include a single manufacturing source for drives and the commonly held belief that quarter-inch technology is not the future of tape backup. Of course, that's what they said about tape storage--yet tape keeps marching along.

VXA-1 And The Torture Tests

Ecrix's 8mm VXA-l drive uses similar technologies to other 8mm helical scan drives, including Exabyte's 8mm and Sony's ALT drives, with its moderate pricing putting it solidly in the server market. In addition, it's reputed to be nearly indestructible. Ecrix and some curious customers have frozen it, boiled it, and dunked it in hot coffee--it just keeps on ticking. It offers three technological innovations: DPF (Discrete Packet Format) increases reliability and accuracy (standing at 100%) by reading and writing data in packet form. VSO (Variable Speed Operation) solves a problem known as "backhitching" or "shoeshining," where the tape frequently stops and repositions itself when the data flow to or from the drive is interrupted. VSO adjusts the tape speed to its computer host, resulting in longer life for the drive. OSO (OverScan Operation) provides high error tolerance by scanning data packets multiple times in one single tape pass. Drive specifications include 33GB native capacity and 3MB/sec uncompressed transfer rates.

Its disadvantages include a single manufacturer and strong competition from DAT. The competing technology that VXA is out to beat is DDS. To that end, Ecrix has announced two new products: the AutoPAK and rakPAK, providing automatic backup and components for rack configurations. It is also developing VXA-2, which is slated to ship in January. With a reasonable MSRP and a native capacity of 50GB and 5MB/sec, Ecrix will continue to court the OEM market.

Decision Points

The server market is very sensitive to price. At the low end of the scale are Travan NS-20, followed closely by VXA-1; DDS-4 and SLR-60 are comparable in the midrange; and SLR-l00 approaches the high range for this market.

Yet purchasing decisions cannot be made on price alone, especially when it means storing your company's lifeline, its data. All four products are reliable and accurate, but the XVA- 1 tops the accuracy list while increasing product life with its VSO technology. DDS-4 and Travan NS-20 are unmatched for their huge installed user bases and mnltiple manufacturers, something the XVA and SLR can't top, and migration paths, clearly an important issue with future data recovery, are laid out for XVA, SLR, and Travan NS, though DDS is not as certain.