For almost four decades, IBM has built upon its mainframe platform’s strengths. Through multiple hardware generations, thousands of companies worldwide have run strategic operations on “blue” hardware. Starting with the System/360, announced in 1964, through the System/370 in the 1970s, System/370-XA and -ESA in the 1980s, and then the System/390 in the 1990s, the IBM mainframe stood apart from the crowd for its Reliability, Availability and Serviceability (RAS) and power.
IBM supports four main operating systems (OSes) for the mainframe:
- z/OS (formerly called OS/390 and MVS, and before that, OS/360), an industrial-strength, transaction-oriented system for business use;
- z/VM (formerly VM/ ESA, VM/XA and VM/SP, and before that, VM/370), a flexible, general computing system originally designed for testing and development, but also used for widely varied applications across the spectrum;
- VSE/ESA (formerly DOS/ VSE), a smaller, transaction-oriented system;
- Transaction Processing Facility (TPF), formerly Airline Control Program, a fast transaction processing environment used by banks, airlines, and credit card processors.
Linux for the mainframe is also up-and-coming (see a related article on page 24).
In October 2000, IBM consolidated its hardware across architecture lines into a single brand — eServer. Instead of selling four separate families of machines with separate management, sales objectives, and identities — customers now purchase eServer solutions. The four hardware architectures endure, of course (see Figure 1), but the goal of the consolidation was to allow a single IBM sales representative to sell the appropriate solution for a problem. No longer must customers discuss mainframe solutions with a mainframe representative, Unix solutions with an RS/6000 representative, etc.
The rebranding was risky, particularly for IBM’s mainframe division. Walking away from almost 40 years of brand equity could have been a disaster. Instead, the strategy has been extremely successful. The eServer name seems to have struck customers’ fancy, and reduced, somewhat, divisional infighting within IBM.
Previously, one group was sometimes prevented from introducing an offering that was viewed as competing with another IBM product. Consider, for example, the P/390, an add-on card in an IBM Intelbased server that emulates System/390 architecture, thus enabling small, relatively low-cost mainframe systems. It barely made it to market because the midrange (RS/6000) group worried that availability of small mainframes would cannibalize sales from their offerings. This was, of course, nonsense. Users with small mainframe workloads who were considering new hardware were asking themselves, “Do I stay on the mainframe, or do I go to Sun/Intel/HP/etc.?” rather than, “Which IBM machine should I buy?” So blocking the P/390, rather than helping one IBM division, would have instead helped IBM’s competitors.
As the hardware converged, the eServer concept also made sense from a manufacturing standpoint. Today, many peripherals can interoperate with multiple eServer hardware families, and this trend will continue. For example, Enterprise Storage Server (“Shark”) disk subsystems can be connected via:
- Enterprise Systems CONnection (ESCON)
- Small Computer System Interface (SCSI)
- FIber CONnector (FICON)
- Fibre Channel.
This means you can use it for all four eServer families. The eServer announcement also allowed IBM to leverage some of the long-recognized strengths of the mainframe across the eServer line. System/390 machines have offered hardware partitioning for over a decade. This facility, formally known as Processor Resource/ Systems Manager (PR/SM), is more commonly referred to as LPAR, for Logical PARtitioning. LPAR, in varying forms, is now available across the eServer line.
zSeries : More Than a New Name