Mainframe -Evolution

Mainframes - Evolution

This article discusses IBM’s evolution over the last few years, and introduces its newest mainframe, the System z9 109. If you don’t recognize the names above, you will by the end of this article!

In 2000, IBM made an audacious change. The industry had enjoyed more than 35 years of mainframe evolution, from System/360 through S/370 to S/390. (The missing link—what should have been called System/380—was instead named System/370 Extended Architecture, or S/370-XA. This anomaly may have resulted simply due to marketing choices, but may also have occurred in part because of the System/38. Released in 1978, the System/38 was descended from IBM’s Future Systems project, which would have replaced the System/370 with a revolutionary but incompatible architecture, and was almost named System/380.)

In a sweeping move, IBM in 2000 renamed all its processor lines as “eServers.” Netfinity PCs became eServer xSeries; RS/6000 RISC machines become pSeries; the AS/400 became iSeries; and the S/390 became zSeries.

The move was more than cosmetic. Historically, the different product lines were developed and sold by different parts of IBM. This led to fragmentation and confusion: The site that needed a medium-size system might be wooed by both a mainframe and an AS/400 sales representative, each claiming their product was superior, even though both were from the same company!

At times, this internal rivalry caused IBM itself difficulty making rational decisions. For example, the IBM PC Server S/390, or P/390, was a PC workstation that contained a special card that provided S/390 processing capability. Introduced in the mid-90s, the P/390 almost didn’t make it to market because the RS/6000 organization within IBM fought against it. Their premise was that the mid-size companies the P/390 would appeal to were their territory, and how dare the mainframe folks poach their customers! Of course, the reality was that companies that needed a smaller mainframe were unlikely to even consider an RS/6000. If forced to migrate to another platform, they’d suddenly find a plethora of choices available, including Sun, HP, and DEC, all of which had successful Unix architectures competing with the RS/6000.

The historical separation across hardware lines also meant that different divisions were solving the same problems with little interoperability: Peripherals such as tape drives were rarely interchangeable, and the machines shared little visual commonality. Since the reorganization, hardware cross-pollination has resulted in iSeries and pSeries machines sharing underlying Power processors; both integrated and outboard xSeries co-processors for iSeries enabling tightly coupled Intel-based computing within an iSeries chassis; and all four families sharing storage, via the TotalStorage “Shark” arrays.

The shift to all-black chassis, echoing the successful tradition of the ThinkPad laptops, also provided a visual family tie. And the rumored “eClipz” project will use multiple common components for machines from embedded systems to future mainframes. The processors and microcode will vary, but the rest of the machine—I/O subsystem, memory, hardware console, power, packaging and cooling—will be shared.

With the eServer re-branding, the IBM server sales teams were also integrated. Instead of selling four different lines, IBM now sold eServers. The move wasn’t without risk. Many thought re-branding was a real gamble and could lead to a dilution of the overall IBM brand, loss of “mind-share” and market share.

Coupled with new, sexier designs and a concurrent push for Linux on all platforms, the eServer consolidation was a success. IBM has led the server market for the last five years. They even created the first ever television advertisements for mainframes!

During this period, the zSeries name became a recognized synonym for mainframe, and four zSeries lines were released: the original z900, followed by its little brother, the z800, and then the z990 and z890.

Operating systems for zSeries share the letter designation: z/OS, z/VM, z/VSE and, most recently, z/TPF. (The slash in the operating system names has been a source of confusion. The rule is actually simple: Software gets a slash; hardware doesn’t. The only tricky part of this is that the architecture is considered software, and is thus“z/Architecture.”)

On July 27, 2005, IBM announced a re-branding and a new family of z/Architecture mainframe processors. The eServer zSeries z990 was replaced by the System z9 109. The short name for these new machines is “z9-109.” This renaming may seem minor, but from a marketing perspective, it represents another significant shift. IBM is once again selling systems rather than servers.

This change from eServer zSeries to System z9 mirrors similar re-branding of iSeries, pSeries and TotalStorage, which are now System i5, System p5 and System Storage respectively. Curiously, xSeries and iSeries machines are still branded as eServer.

IBM taxonomy and marketing theology are complex but worth understanding. Prior to this announcement, the mainframe brand was IBM eServer; the family was zSeries; and the model was 900, 800, 890, or 990. Now, the brand is IBM; the family is System z9; and the model is 109. Additionally, there are five configuration models available: S08, S18, S28, S38, and S54.

To make things more complex, each IBM product has a name, such as “System z9 109,” as well as one or more product numbers. A product number consists of a four-digit number, called a machine type, followed by a dash and a three-character model, which is the same as the configuration model listed above.

Like its zSeries predecessors, the z9-109 is available as a single machine type (2094). The five models are built on the z990 “book” concept of modules containing multiple CPUs, only some of which need be enabled, and continue the IBM mainframe tradition of upgradeability across the line, ranging from a single 600 MIPS engine to a 54-way, offering a staggering 18,000 MIPS.

The model scheme is simple. Each adds one “book” to the previous model, and for all, the numeric portion indicates the maximum number of CPUs available on that machine. The exception is the S54, which is a four-book machine like the S38, but with extra CPUs enabled on each book. With the eight System Assist Processors (SAPs) and two spares, the 64 physical processors in an S54 leave 54 available for configuration as CPs (normal z9 CPUs), IFLs (full-speed processors that can run Linux only on zSeries or z/VM, thus reducing license fees for z/OS shops), zAAPs (Java engines), or additional SAPs.

Figure 1 shows how you can configure five models ranging from the S8 to S54. Suffice it to say this mid-life kicker to the existing hardware architecture provides more, better, faster mainframe processing than ever before. With ever-increasing processing demands, particularly in the growth of Linux on zSeries, the z9-109 offers uch-needed relief for high-end shops.

Beyond just “feeds and speeds,” IBM is touting the z9-109 as an example of “holistic balanced system design.” This somewhat touchy-feely sounding phrase is relevant, as it expresses what mainframers have long recognized: Clock speed isn’t everything. Even the fastest Intel processor can be easily brought to its knees by a single application (try burning a DVD and doing almost anything else simultaneously!), whereas mainframes have for decades supported many hundred simultaneous users, with 100 percent CPU utilization, thousands of devices active, and good response time. This isn’t just due to operating system design; it’s also due to an architecture that emphasizes these traits. Intel hardware spent 20-plus years focusing on clock speed. For much ofthat time, PC I/O architecture made relatively minor advances, and most machines can be easily bottlenecked by I/O limitations.

IBM believes a key feature is balancing I/O capability, MIPS (clock speed), n-way multi-processing, and main storage. The System z9 machines exemplify that philosophy. Figure 2 shows the evolution, from the G5 and G6 9672s, through the zSeries machines, to the z9-109, which is the most evenly balanced machine yet.

Most of the readers will recognize Freeway, Raptor, Ptero, and T-Rex as the fairly public IBM codenames for the z900, z800, z990, and z890, respectively. These names are interesting because they reflect the evolution of the technology. Freeway was the “big road” to the future—the first 64-bit machine, replacing the 31-bit machines that were becoming too small. Raptor, T-Rex, and Ptero (short for Pterodactyl) were dinosaurs. That generation of naming reflected the perception that mainframes were huge, powerful—and from the past. IBM has clearly re-thought that approach; mainframes have proven their staying power, rather than becoming extinct.

Thus with the z9-109, IBM has gone from dinosaurs to gods. Danu is the Irish/Celtic Earth Goddess, matriarch of the Tuatha D_ Danann (“People of the Goddess Danu”), and mother of many Irish Gods, including the Dagda, God of the Earth and treaties and ruler over life and death (who is also sometimes listed as her father); Dian Cecht, God of healing; Ogma, God of speech, said to lead his followers around by chains of gold and amber, leading from his tongue to their ears; Lir, God of the sea; and Lugh, the “Shining One,” God of the sun. Danu’s Welsh equivalent is the goddess Don.

The wealth of possibilities for naming, using this new scheme, promises a rich future for the IBM mainframe. It seems only appropriate that the most powerful general-purpose computers on Earth are named after a deity!


References:

www.zjournal.com