Perspectives: The Tape Of Things To Come

Back up, back up was the cry of the IT industry to its users in the 80s. And although technology has moved on, proper back up is still vital, says Sean Hallahan

The devolution of computing power to the user with the arrival of the PC brought enormous benefits to business and to individuals.

But along the way, many of the established practices that had hitherto been taken as axiomatic in the world of centralised computing were jettisoned, none more so than backing up data on a regular basis. Not that users were not warned of the perils of failing to back up their data.

Throughout the mid 80s there were almost weekly bulletins warning that if users did not back up regularly they risked putting their business in jeopardy. The problem was that most of these warnings came from the manufacturers and resellers, companies with a vested interest in selling another piece of kit to be added on to a basic PC configuration.

But the problem of backup remains a critical one according to consultancy Bloor Research. In its report, New Computer Hardware: Options and Comparisons, Bloor Research points out that the growth in distributed computing has accentuated the problem of backing up data.

?As with every other aspect of IT, the trend to distribute storage along with processing capability has complicated the management process. The major concern can be summarised as follows: it is estimated that fewer than 50 per cent of PC users back up their data regularly; it is also estimated that currently many, perhaps the majority, of large installations have more than 50 per cent of their data stored outside the mainframe glasshouse; it is also known that over 70 per cent of organisations that lose their data as a result of some catastrophic system failure, cease trading two weeks after the disaster.?

The favoured back-up device of the 1980s was what was then known as a tape streamer. The difficulty suppliers had was in persuading users that buying an expensive piece of kit merely to back up a system was a necessity, and not just another way to screw more money out of a customer.

Matters were further confused by the fact that tape technology, while simple on the surface, is in fact highly complex, with a number of competing would-be standards on the market. These diverse standards, in a world where compatibility and standardisation are taken for granted, made users reluctant to purchase a piece of kit that could be made obsolete by the march of time and technology.

There are now two major technologies in the tape market: digital audio tape (DAT) and digital linear tape (DLT), plus several up-and-coming competing technologies.

Sony has introduced its own technology, advanced intelligent tape (AIT), which is looking to challenge DLT, and tape supplier Cristie favours another alternative ? magnetic linear recording (MLR). DLT technology is produced by Quantum and is favoured by Compaq and Hewlett Packard as their main storage medium for large systems.

The birth of DAT systems represented the first major technological breakthrough in the tape market for many years. DAT increased the density of storage by an order of magnitude and cut the cost of storing a megabyte of data by a factor of 20. The increased recording density also reduced the size of the media down to a cartridge the size of a floppy disk. In the early 90s, backing up a gigabyte of data could take up to two hours. A gigabyte of storage using DAT can be achieved in about half an hour.

Although DAT improved the speed of storage, tape is still the slowest of all the media. In hierarchical order, solid state disks are the fastest, followed by hard disks, read/write optical disks, Worm (write once read many) optical disks and tape systems. For all that, tape sub-systems are considered to be highly reliable ? as they should be, since they were the major storage devices until they were superseded by magnetic disks in the early 70s.

In the days when the mainframe data centre dominated the IT industry, back-up systems were handled routinely by the data processing staff. The advent of the PC and the PC network relegated the back-up tasks to the user, or more probably to the user?s secretary or administrative assistant. In general, though not invariably, DAT is favoured by the smaller users and DLT by larger users with servers and networks.

?The tape market is a changing one,? says Dave McClelland, a storage consultant with the distributor Azlan. ?Traditionally people were using DAT, which had a period where it was flavour of the month. It had a small form factor which fitted neatly into the PC and could store eight gigabytes of data. But a couple of things have happened that has changed that. People have to back up more often and DAT was not really designed for that heavy-duty load. DAT 120 metre tape is not robust enough and you can have problems restoring data.?

The need to save greater quantities of data, and to save it more often, is driving the demand for the more robust DLT tapes. According to McClelland, there is an ever-increasing need for greater capacity per tape which DLT provides. ?You can get 20 gigabytes native on one DLT tape, and with compression, 40 gigs per tape. DLT is a half-inch tape and has a longer duty cycle and shelf-life of five years against DAT?s six months.?

There are also pressing commercial reasons why there is a greater demand for DLT. With many companies now operating a 24-hour, seven-days-a-week business, the time frame users have for tape back-up is considerably reduced. When the pace of business life was not so frantic, and the mainframe and mid-range systems dominated the IT industry, backing up data usually took place overnight or at weekends.

The latest offering from Quantum, the DLT 7000, can store 35Gb in native mode and 70Gb when compressed. The earlier model, the Quantum 4000, has a throughput rate of 2Mbps, and the 7000 3Mbps.

McClelland believes that while DLT is the most popular for heavy duty users, Sony?s AIT technology may yet present a challenge. ?AIT is a lot cleaner than DLT and has an 8mm format. Its capacity is not quite as high as DLT, but it shows promise ? we have only just taken delivery of the product so it is a bit early to say,? he says.

According to Grant Morgan, product manager at Ideal Hardware, the demand for tape systems has been continually growing because servers are running more critical business applications. Where in the past back-up systems may have been something of an afterthought, users now recognise that they cannot afford to lose data. ?Storage products do three things: they read, they write and they crash,? he says.

But Morgan believes that users now recognise the need to have an adequate back-up system because of the critical nature of their applications to the running of their business. He says DAT is still selling well, although being pressed hard by DLT. But DLT may soon be facing a challenge from Sony?s AIT. ?AIT has the same, if not better, reliability than DLT in a 3.5in form factor,? says Morgan.

One of the major problems with DLT is that there has been a shortage of products from the primary supplier, Quantum, which Morgan believes will boost the sales of AIT systems. ?Quantum has quite often held the market to ransom. Because they have some large OEMs, one of them quite often gets the full batch of products leaving little for the rest of the market. We are still committed to DLT because it is big business for us, but I expect AIT to take 10 per cent of the market this year,? he says.

What will promote the fortune of AIT even further is if it is adopted as standard by one of the major PC manufacturers such as Compaq. Morgan believes that the DLT market will also continue to grow and that DAT will remain a powerful technology because of the number of companies backing it as a preferred option.

Robin Burton, a director of Cristie, believes that the DLT bandwagon may now be running out of steam and that AIT is too new for users and analysts to assess its impact on the market. He describes MLR as new ?old technology? in that it is a quarter-inch tape upgraded by applying thin film technology.

The advent of client/server systems has raised the profile of the back-up tape industry. ?There are no virgins out there in the server market,? says Burton. He believes that all of the different types of technology have their place. ?It all depends on where the customer started from,? he says. DAT, DLT, and MLR all have their place because they have an existing installed base, according to Burton. But he is less certain about the future of AIT. ?It is the new kid on the block and we have looked at it but decided not to go with it at present,? he says.

In many ways, the actual tape technology is less important than it used to be because of the use of auto-loaders, Burton believes. He also identifies another trend in the industry ? where companies have a distributed system there is a growing tendency for users to back up to the corporate mainframe if they have one. ?The trend is to back up to the mainframe, which in theory leaves no room at all for DAT, DLT or MLR.?

In practice things are not quite so simple. Recovering from a mainframe server failure can be a long business, and many companies will continue to back up locally as well as to the corporate mainframe. ?IT departments are saying that they have their work cut out just backing up the servers, let alone the PCs,? says Burton.

The cost of a tape back-up system amounts to only three to four per cent of the total sale of a PC, according to Burton. The devices may not command a high profit margin for dealers, but as McClelland points out, tape storage systems are a strategic purchase which may well involve the user requiring a great deal of hand holding. In Azlan?s view, it is the duty of the distributor to educate the both the dealer and the user in the importance of backing up their data.

It is probable that no one technology will come to dominate the tape market in the foreseeable future. DAT, DLT, MLR and AIT will probably all have their place, but the longer term future is less certain. If, as some analysts suspect, the network computer or thin client system takes off, then the requirements for localised backup will diminish greatly.

Oracle chairman and chief executive Larry Ellison continually makes the point that the network computer removes the need for individual users to back up their own systems which will be handled separately on the fat client server. Backing up data locally is seen by many users as a chore and one with which they could well do without.

No one is going so far as to predict that the PC and the PC network will disappear altogether, but if the thin client model is adopted to any great degree then there is no doubt that the sales of PCs will fall and with them the requirement for back-up systems.

Yet for the foreseeable future, there will be a continuing demand for tape back-up systems on both the server machines and the clients, whether they are PCs or workstations.