IBM Z

The zSeries, zEnterprise, System z and IBM Z families were named for their availability – z stands for zero downtime.

The systems are built with spare components capable of hot failovers to ensure continuous operations.

First layer virtualization is provided by the Processor Resource and System Manager (PR/SM) to deploy one or more Logical Partitions (LPARs).

[citation needed] IBM Z's PR/SM and hardware attributes allow compute resources to be dynamically changed to meet workload demands.

CPU and memory resources can be non-disruptively added to the system and dynamically assigned, recognized, and used by LPARs.

[16][17] A z14 system can have a maximum of 240 Processing Unit (PU) cores, 170 of which can be configured to the customer's specification to run applications and operating systems, and up to 32 TB usable redundant array of independent memory (RAIM), some of which can be configured as Virtual Flash Memory (VFM).

The focus of the IBM Z systems are pervasive encryption as the z14 processor has plenty of hardware assisted cryptography features (AES, DES, TDES, SHA, Random number generator).

According to IBM, it is the most scalable Linux server available with support for up to 6,000[23] virtual machines in a single-footprint.

In June 2014, IBM announced[25] it had shipped its first Enterprise Cloud System to Vissensa, a UK-based managed service provider.zEnterprise Business Class 12 – The zBC12 is an entry-level single-rack solution, was introduced in July 2013 and is available in two hardware models, the H06 and the H13.

zEnterprise Enterprise Class 12 – The zEC12 is a high-end dual-rack solution, and available in five hardware models: H20, H43, H66, H89 and HA1.

Additional cores are reserved as spares, SAPs and IFPs.Introduced in August 2012, the zEnterprise EC12 is based on the zEC12 chip, a 5.5 GHz 8-core out-of-order CISC-based z/Architecture processor.

The EC12 has 50% higher total capacity than the z196 (up to 78,000 MIPS), and supports Transactional Execution and Flash Express – integrated SSDs which improve paging and certain other I/O performance.

zEnterprise, announced in July 2010, with the z196 model, was designed to offer both mainframe and distributed server technologies in an integrated system.

The zEnterprise System consists of three components:[29] The zEnterprise is designed to extend mainframe capabilities – management efficiency, dynamic resource allocation, serviceability – to other systems and workloads running on AIX on POWER7, and Microsoft Windows or Linux on x86.

The z114 supports up to 248 GB (usable) of redundant array of independent memory (RAIM).zEnterprise 196 – The z196 is a high-end dual-rack solution, and available in five hardware models: M15, M32, M49, M66 and M80.

[32] Additional cores are reserved as spares and as SAPs.The 196's microprocessor is the z196 chip, a 5.2 GHz quad-core out-of-order CISC-based z/Architecture processor.

The z196 can have a maximum of 24 processors giving a total of 96 cores, 80 of which are directly available to run operating systems and applications.

The System z9 servers offered: Specific models from this family include: Announced on October 3, 2000, and available on December 18, the eServer zSeries 900 (z900 for short) was the first to feature the 64-bit z/Architecture extension of the S/360 architecture, still retaining the support for the 31-bit and 24-bit addressing programs back to 1964.

[37][38] In 2002, IBM launched the z800, a lower-end mainframe featuring five Blue Flames clocked at 625 MHz, of which up to four can be Central Processors, all sharing an 8 MB L2 cache.

[40] Featuring IBM's first superscalar CMOS mainframe processors, a dual-core chip contained 121 million transistors across 266 mm2, and was manufactured in a 130 nm process, drawing 55 Watts at 1.2 GHz in the z990.

[44] The number of logical partitions was doubled to 30, and the maximum distance of Parallel Sysplex rose to 100 km.

[39] In 2004, IBM extended the idea of lower-cost restricted processors (first introduced in 2000 in the form of IFL, for use by Linux on IBM Z only) that are not permitted to run the traditional mainframe OSes (z/OS, z/VM, z/VSE, and z/TPF), by the addition of z Application Assist Processor dedicated to Java and XML processing.

The IFL and zAAP are physically the same as the Central Processors, but IBM charges lower fees for their use.

The Resource Manager can monitor the various platforms for signs of bottlenecks or faults and modify the overall system to recover, maintaining a specified quality of service level.

[56] Each purchased PU (processor unit) is characterized as one of a variety of types: Also it's possible to run a zAAP-eligible workload on zIIPs if no zAAPs are enabled.

IBM does not impose any software charges on work that is dispatched on zAAP and zIIP processors.

The addition of IFLs, zAAPs, zIIPs, ICFs, SAPs or IFPs does not change the system capacity setting or its MSU rating, only CPs do.