IBM Mainframe

IBM Mainframes

 

IBM mainframes are large computer systems produced by IBM since 1952.

A typical IBM mainframe computer would look like below:-

 

IBM zSeries z800 Mainframe Computer

From 1950s-60s IBM manufactured and marketed several large computer models known as IBM 700/7000 series. The first generation 700s were based on Vaccum Tubes, while the later, the second generation 7000s used Transistors. These machines established IBM's dominance in Electronic Data Processing("EDP").  The mainframe computer costed over 2M USD in mid 1950's.The latest mainframe computers are IBM z10 EC(Enterprise Class) which costs around 1M USD announced on February 26th, 2008.

 

There were two categories of machines with completely different instruction sets. One dealt with engineering and scientific data and the other set of machines dealt with commercial data. The IBM Mainframe systems are mainly designed for Throughput and Relaibality. They are not Super Computers and they are not designed for number crunching.


Mainframes usually are the computers that work on tons of smaller and simpler transactions. For example:- To process millions of card swipes and account transfers that occur daily, 96 out of 100 banks and 23 out of 25 US retailers use mainframe computers. Airlines for booking tickets, processing data when on flight, uses mainframe computers.


Building a mainframe computer is very complex, they use special CPU's and additional processors called System Assistant Processors (SAP's) which move the data very quickly around. If you take the latest z13 IBM mainframe computer each Individual I/O card  (upto 160) has its own processing cores, upto 2 per channel on dual channel card. (so 4 per I/O card and upto 640 Processors cores overall Just for I/O excluding SAP's).


Part of the Reason, to support this much I/O, is to ensure that they are relaible. They are sub-systems built into mainframes which do the Z/TPF (transaction processing).

 

Initially IBM sold the machines without any software. The users who bought the machines are expected to write their own softwares and run their own programs. These programs were manually initiated, one at a time. Later IBM provided compilers for newly developed higher-level programming languages Fortran and COBOL.

 

The first operating systems for IBM computers were written by IBM Customers who did not wish to have their very expensive IBM mainframe machines sitting idle while the operators set up jobs manually, which means the IBM computer was idle and it had to wait for the operator to submit a job onto it manually. Therefore the Customers of IBM (General Motors and North American Aviation) and their reasearch divisions  came up with a operating system which was based on a system monitor created in 1955 by programmers of General Motors for its IBM 701.

 

It is called GM-NAA I/O. The main function was to automatically execute a new program once the one that was being executed had finished (batch processing). IBM enhanced one of GM-NAA I/O's successors, the SHARE Operating System(SOS) and provided it to customers under the name IBSYS.

As the software became more important and complex, the cost of supporting it on so many different designs became burdensome, and this was one  of the factors which led IBM to develop System/360 and its operating systems. (announced in 1964 and delivered between 1965 and 1978)

 

The second generation(transistor-based) products were a mainstay of IBM's business and IBM continued to make them for several years after the introduction of the System/360.

 

Prior to System/360, IBM also sold computers smaller in scale that were not consisdered mainframes, though they were still bulky and expensive by modern standards.  IBM had difficutly getting customers to upgrade from the smaller machines to the mainframes because so much software had to be rewritten.

 

All this changed with the announcement of System/360(S/360) in April, 1964. The System/360 was a single series of compatible models for both commercial and scientific use. The number "360" suggested a "360 degree" or "all-round" computer system. The System/360 was also the first computer in wide use to include dedicated hardware provisions for the use of operating systems. Hardware memory protection was provided to protect the operating system from the user programs (tasks) and the user tasks from each other.

 

The System/360 later evolved into S/370, S/390 , the 64-bit zSeries (z890,z800, z900 and z990 in year 2000), IBM System z(April 2006) (Viz., IBM system z10 and IBM System z9) and zEnterprise machines(Enterprise Class and Business Class)  introduced in the Year 2010.

("IBM z Systems" ~ Year 2000 after System/390).

And latest IBM mainframe computers are z14 and z13.

 

So, in reverse chronological order it is as follows:-

1. IBM z14
2. IBM System z13
3. IBM zEnterprise System
4. IBM System z10
5. IBM System z9
6. IBM zSeries family

 

 

The following picture shows an IBM zEnterprise EC12 with cover removed. The interior is lit to better see the various internal parts.

 

IBM zEnterprise EC12

 

The following picture shows a trio of IBM zEnterprise mainframe computers which are EC12,BC12 and Bladecenter Extension.

 

 

EC12 | BC12 | Bladecenter Extension Mainframe Computers

 

 

z stands for ZERO DOWNTIME

 

 

System/370 introduced Virtual memory capabilites. The Virtual memory capabilites also allowed the system to support virtual machines. The VM/370 Hypervisor would run one or more virutal machines running either Standard S/360 or S/370 operating systems.

 

IBM z13 is the last z Systems server to support running an operating system in ESA/390 (Feb 17, 2016) architecture mode. The systems are built with spare components capable of hot failovers to ensure continous operations. The IBM Z family maintains full backward compatibility. In effect, currect systems are direct, lineal descendants of System/360, announced in 1964, and the System/370's from 1970's. Many applications written for these systems can still run unmodified on the newest System z over five decades later.

 

IBM zEnterprise System

 

Let us see what the latest IBM mainframe computers offer its customers. The IBM zEnterprise system, announced in July 2010, with z196 model, is designed to offer both mainframe and distributed server technologies in an integrated system.

 

The zEnterprise System consists of three components.

1. System z server.
2. IBM zEnterprise BladeCenter Extension (zBX).
3. IBM zEnterprise Unified Resource Manager (zManager), a Management Layer.

zManager provides a single management view of zEnterprise resources.

 

The zEnterprise is designed to extend mainframe capabilites - management efficiency, dynamic resource allocation, serviceability to other systems and workarounds running on AIX on POWER7 and Microsoft Windows or Linux on X86.

 

zEnterprise BladeCenter Extension (zBX) is an infrastructure component that hosts both general purpose blade servers and appliance-like workload optimizers which can all be managed as if they were a single mainframe. The zBX supports a private high speed internal network that connects it to the central processing complex, which reduces the need for networking hardware and provides inherently high security.

 

The zManager integrates the System z and zBX resources as a single virtualized system and provides unified integrated management across zEnterprise System. It can identifiy system bottlenecks or failures among disparate systems and if a failure occurs it can dynamically reallocate system resources to prevent or reduce application problems. It also provides energy monitoring, resoruce management, increased security, virutal networking and information management from a single user interface.

 

Highlights of original z196 include:

• BladeCenter Extension (zBX) and unified Resource Manager
• Upto 80 Central Processors (CPs)
• 60% higher capacity than the z10 (Upto 52000 MIPS)
• Twice the memory capacity
• 5.2 GHz quad-core chips.

 The newest zEnterprise, the EC12, as shown in the above picture, which was introduced in 2012 includes:

 

• upto 101 central processors (CPs)
• 50% higher capacity than the z196 (Upto 78000 MIPS)
• Transactional Execution
• 5.5 GHz hex-core chips.
• Flash Express - Integrated SSDs which improve paging and certain other I/O Performance.

 

 On April 8, 2014, in honor of 50th anniversary of the System/360 mainframe, IBM announced, the release of its first converged infrastructure solution based on mainframe technology. Dubbed the IBM Enterprise Cloud system, this new offering combines IBM mainframe hardware, software and storage into a single system and is designed to compete with competitive offerings from VCE, HP and Oracle. According to IBM, it is the most scalable Linux server available with support for upto 6,000 virtual machines in a single-foot print.

 

 Regards

Sai