IBM has a problem. The 3990-6 disk controller, used with Ramac 9391/9392 RAID 5 disk subsystems, appears to be incapable of providing support for more than 180Gb of disk capacity – or two full 9391 racks at 90Gb each (CI No 2,630). The performance of 3990-6/Ramac subsystems has been so poor that IBM has doubled or quadrupled a customer’s cache memory at no charge or, in exceptional cases, installed an entire additional 3990. In general, it seems 3990-6 controllers with 128Mb of cache (the most popular configuration) do not deliver satisfactory response times. Similar performance considerations apply to the Ramac 9394/9395 models with built-in cache controllers: these models do not provide all the features of a 3990-6 and are no faster. In most cases, larger cache can up performance of a 3990-6/Ramac subsystem to satisfactory levels with current Ramac disks. But until IBM can ship a significantly faster controller (the rumoured Sea Star, expected in mid-1996) there is little reason for it to offer more capacious Ramac disk modules. Jim Porter of Disk/Trend, Mountain View believes that the delays in the Ramac programme could persist so long that IBM will abandon the 4Gb drives once expected to supplant the current 2Gb disks and instead move all the way to 8Gb technology, thereby quadrupling the capacity of each Ramac four-drive module. IBM may have controller problems, he points out, but it continues to improve its disk drive technology. The high cost of a 3990-6 controller already makes Ramac subsystems costly against alternatives offered by IBM’s competitors, despite IBM’s deep discounting.

Mow down

Currently, IBM sells its 18-month-old 3990-6 controller at well under half of its original list, while discounts in excess of 40% on Ramac storage racks and disk drawers are commonplace. But the discounts may not yet be deep enough, and IBM may be providing a protective umbrella for EMC Corp. This tale is told in financial reports, which show that EMC has enjoyed higher gross margins than IBM. IBM has never killed off a mainframe disk or controller early in its life, but this time things are different. So the big question is when, not if, IBM will replace its current controller and offer a more capacious disk array behind it. If IBM waits long enough, it could possibly be forced to field an entirely new mainframe disk subsystem, one that more closely resembles the current EMC or forthcoming Hitachi offerings. In that case, the current products will quickly lose market value… and that will be a problem for IBM’s captive leasing companies. IBM has retained ownership of nearly all the Ramac disks it has installed in the US and Europe, in large measure because it bundled an inexpensive capacity upgrade offer with its leases. If IBM quickly obsoletes the Ramac or the 3990-6 controller, it will have to face a very substantial loss – one that it can defer, through the magic of lease accounting, but not in the end avoid. In the meantime, EMC is scrambling to maintain its lead and do in Europe as it has done in the US. With the latest enhancements to Symmetrix, customers are likely to see EMC’s products not only as seasonal leaders but also as safe investments for the long haul. Hitachi expects to ship its first 7700 arrays in July. While these are probably not going to be the market’s price leaders, technical analysts expect them to be the fastest RAID 5 products available. We expect Hitachi to be production-limited at first, but by first half 1996 the race between Hitachi and EMC could be close. IBM is likely to fall to third place in terms of shipments as measured by capacity… and become concerned that an all-out price war would constrain its freedom to price future mainframe disk subsystems at satisfactory levels. The disk problem is severe enough to make industry wags wonder whether Lou Gerstner will mow down Ed Zschau, IBM’s disk enchilada, before Richard Thoman, the company’s ex-Nabisco PC poobah. But maybe the ever efficient Gerstner will save time and sack them simultaneously while praising both for th

eir contributions to the great IBM turnaround. – by Hesh Wiener from the April 1995 edition of Infoperspectives International, published by Technology News Ltd, (C) 1995 Technology News Ltd.