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In December, 2001, IBM designated all its mainframes with the name eServer zSeries, with the e depicted in IBM's well-known red trademarked symbol. Nonetheless, IBM didn't give the previous servers new names, so the term zSeries now popularly refers only to IBM's first line of 64-bit mainframes, starting with the zSeries 900. In July 2005, IBM rebranded the server line again, to System z, but again not renaming previous servers. At the same time IBM announced a new brand name (System z9) using it to announce the latest generation System z9-109 servers which add support for multiple processor books per server, quadrupling the maximum processor power and I/O capabilites with the new line.

However, the term "zSeries" is still the most popular way to refer to all IBM mainframe servers, propably because the zSeries, introducing 64-bit to the mainframe world was a breakthrough in raw processor performance and marked a historic milestone since it was the first implementation of the z/Architecture, a big departure from the previous architectures which were limited to 31-bit addressing, which was introduced by the System/370 in the 1970s. In its 64-bit mode the CPU became free from this legacy and its legacy became history.

The IBM eServer zSeries line succeeded the IBM System/390 (S/390 for short) which were based on the ESA/390 architecture while ensuring full compatability to it. Thus, zSeries servers are the direct, lineal descendents of the IBM System/360, announced in 1964, and the 1970s System/370, and applications written for the 24-bit-addressing/32-bit-data System/360 can still run, unmodified, on the newest System z9 over four decades later, with few exceptions.

Major features of the eServer zSeries family:

Based on z/Architecture (64-bit real and virtual addresses)
Offers up to 14 central processors (CPs) per frame (rack) coupled in up to a 32-frame Sysplex — with each frame physically separated up to 100 kilometers
Supports the Linux, z/OS, z/VM, z/VSE, z/TPF, and MUSIC/SP operating systems
S/390 ESA (31-bit) applications are fully compatible with z/Architecture

The System z9 servers add on top of that:

Support for multiple processor books per machine, up to 4 books. This allows to 54 central processors (CPs) per frame (rack).
multible I/O channel subsystems per machine, boosting the previous limit of 65536 I/O channels by 4 times.

The System z9-109 (S54), with up to 54 "characterizable" PUs (processors), is currently the most powerful IBM mainframe available, reportedly capable of performing approximately 18,660,000,000 core instructions per second. A single S54 can typically process one billion or more business transactions per day. The 54 PUs can be characterized (configured) for a variety of purposes including general purpose processing (CPs), zAAPs, IFLs, and ICFs (coupling facilities).

A direct comparison of zSeries servers with other computing platforms is difficult. zSeries servers are unique in providing processing power for business-critical, high volume transaction processing and databases. For example, zSeries servers offload such functions as I/O processing, cryptography, memory control, and various service functions (such as accounting and logging) to dedicated processors. These "extra" processors are in addition to the (up to) 54 main CPs per frame. The zSeries servers also effectively execute every instruction twice in order to assure processing integrity. If the instruction results differ, the zSeries server retries the instruction. If the instruction still fails, the zSeries/z9 server will shut down the failing processor and shift workload, "in flight," to any surviving processors, including one or more spares. (The zSeries, for example, always has at least two spares per processor book available.) The IBM mainframe then "calls home" (automatically places a service call to IBM), and an IBM service technician soon arrives with a replacement part (possibly even a new processor book, consisting of a group of processors). With System z9 servers, the technician installs the new book removes the old one without interruption to running applications. (Note that IBM mainframe processors have a reported 40 year MTBF.) Similar design redundancies exist in memory, I/O, power, cooling, and other subsystems. All these features exist at the hardware and microcode level, without special application programming. The same concepts extend to coupled frames separated by up to 100 kilometers in a Geographically Dispersed Parallel Sysplex.

zSeries servers are well regarded for their reliability, availability, integrity, and mixed workload performance -- characteristics not typically measured in computing benchmarks. They tend to have higher costs of acquisition ("price") and lower costs of ownership ("TCO") than other platforms, especially when running a variety of business-critical applications concurrently (so-called mixed workload). They are the enterprise workhorses in numerous industries including government, financial services, retail, and manufacturing.

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 In December, [[2001]], [[IBM]] designated all its [[mainframe]]s with the name '''eServer zSeries''', with the '''e''' depicted in IBM's well-known red trademarked symbol. Nonetheless, IBM didn't give the previous servers new names, so the term '''zSeries''' now popularly refers only to IBM's first line of 64-bit mainframes, starting with the zSeries 900. In July 2005, IBM rebranded the server line again, to ''System z'', but again not renaming previous servers. At the same time IBM announced a new brand name ([[System z9]]) using it to announce the latest generation System z9-109 servers which add support for multiple [[processor book]]s per server, quadrupling the maximum processor power and I/O capabilites with the new line.
-However, the term "zSeries" is still the most popular way to refer to all IBM mainframe servers, propably because the zSeries, introducing [[64-bit]] to the mainframe world was a breakthru in raw processor performance and marked a historic milestone since it was the first implementation of the [[z/Architecture]], a big departure from the previous architectures which were limited to [[31-bit]] addressing, which was introduced by the [[System/370]] in the 1970s. In its 64-bit mode the CPU became free from this legacy and its legacy became history.
+However, the term "zSeries" is still the most popular way to refer to all IBM mainframe servers, propably because the zSeries, introducing [[64-bit]] to the mainframe world was a breakthrough in raw processor performance and marked a historic milestone since it was the first implementation of the [[z/Architecture]], a big departure from the previous architectures which were limited to [[31-bit]] addressing, which was introduced by the [[System/370]] in the 1970s. In its 64-bit mode the CPU became free from this legacy and its legacy became history.
 The IBM eServer zSeries line succeeded the IBM '''System/390''' ('''S/390''' for short) which were based on the [[ESA/390]] architecture while ensuring full compatability to it. Thus, zSeries servers are the direct, lineal descendents of the IBM [[System/360]], announced in [[1964]], and the 1970s [[System/370]], and applications written for the [[24-bit]]-addressing/[[32-bit]]-data System/360 can still run, unmodified, on the newest System z9 over four decades later, with few exceptions.

Revision as of 15:30, 17 February 2006

See also

External links