System z: I/O Interoperability Evolution – From Bus & Tag to FICON

Since the introduction of the S/360 Mainframe in 1964 there has been a gradual evolution of I/O connectivity that has taken us from copper Bus & Tag to fibre ESCON and now FICON channels.  Obviously during this ~50 year period there have been exponentially more releases of Mainframe server and indeed Operating System.  In this timeframe there have been 2 significant I/O technology milestones.  Firstly, in 1990, ESCON was part of the significant S/390 announcement (MVS/ESA), where migration to ESCON was a great benefit, if only for replacing the heavy and big copper Bus & Tag channels.  Secondly, even though FICON was released in the late 1990’s, in 2009 IBM announced that the z10 would be the last Mainframe server to support greater than 240 native ESCON channels.  Similarly IBM declared that the last zEnterprise server to support ESCON channels are the z196 and z114 servers.  Each of these major I/O evolutions required a migration philosophy and not every I/O device would be upgraded to support either native ESCON of FICON channels.  How did customers achieve these mandatory I/O upgrades to safeguard IBM Mainframe Server and associated Operating System longevity?

In 2009 it was estimated ~20% of all Mainframe customers were using ESCON only I/O infrastructures, while only ~20% of all Mainframe customers were deploying a FICON only infrastructure.  Similarly ~33% of z9 and z10 systems were shipped with ESCON CVC (Block Multiplexor) and CBY (Byte Multiplexor) channels defined, while ~75% of all Mainframe Servers had native ESCON (CNC) capability.  From a dispassionate viewpoint, clearly the migration from ESCON to FICON was going to be a significant challenge, while even in this timeframe, there was still use of Bus & Tag channels…

One of the major strengths of the IBM Mainframe ecosystem is the partner network, primarily software (ISV) based, but with some significant hardware (IHV) providers.  From a channel switch viewpoint, we will all be familiar with Brocade, Cisco and McData, where Brocade acquired McData in 2006.  However, from a channel protocol conversion viewpoint, IBM worked with Optica Technologies, to deliver a solution that would allow the support for ESCON and Bus & Tag channels to the FICON only zBC12/zEC12 and future Mainframe servers (I.E. z13, z13s).  Somewhat analogous to the smartphone where the user doesn’t necessarily know that an ARM processor might be delivering CPU power to their phone, sometimes even seasoned Mainframe professionals might inadvertently overlook that the Optica Technologies Prizm solution has been or indeed is still deployed in their System z Data Centre…

When IBM work with a partner from an I/O connectivity viewpoint, clearly IBM have to safeguard that said connectivity has the highest interoperability capability with bulletproof data exchange attributes.  Sometimes we might take this for granted with the ubiquitous disk and tape subsystem suppliers (I.E. EMC, HDS, IBM, Oracle), but for FICON conversion support, Optica Technologies was a collaborative partner for IBM.  Ultimately the IBM Hardware Systems Assurance labs deploy their proprietary System Assurance Kernel (SAK) processes to safeguard I/O subsystem interoperability for their System z Mainframe servers.  Asking that rhetorical question; when was the last time you asked your IHV for site of their System Assurance Kernel (SAK) exit report from their collaboration with IBM Hardware Systems Assurance labs for their I/O subsystem you’re considering or deploying?  In conclusion, the SAK compliant, elegant, simple and competitively priced Prizm solution allowed the migration of tens if not hundreds of thousands of ESCON connections in thousands of Mainframe data centres globally!

With such a rich heritage of providing a valuable solution to the global IBM Mainframe install base, whether the smallest or largest, what would be next for Optica Technologies?  Obviously leveraging from their expertise in FICON channel support would be a good way forward.  With the recent acquisition of Bus-Tech by EMC and the eradication of the flexible MDL tapeless virtual tape offering, Optica Technologies are ideally placed to be that small, passionate and eminently qualified IHV to deliver a turnkey virtual tape solution for the smaller and indeed larger System z user.  The Optica Technologies zVT family leverages from the robust and heritage class Prizm technology, delivering an innovative family of virtual tape solutions.  The entry “Virtual Tape In A Box” zVT 3000i provides 2 FICON channel interfaces and 4 TB uncompressed internal RAID-5 disk space, seamlessly interfacing with all System z supported tape devices (I.E. 3490, 3590) and processes.  A single enterprise class zVT 5000-iNAS node delivers 2 FICON channel interfaces, NFS storage capacity from 8TB to 1PB in a single frame with standard deduplication, compression, replication and encryption features.  The zVT 5000-iNAS is available with multi-node configuration support for additional scalability and resiliency.  For those customers wishing to deploy their own choice of NFS or FC storage subsystem, the zVT 5000-FLEX allows such connectivity accordingly.

In conclusion, sometimes it’s all too easy to take some solutions for granted, when they actually delivered a tangible and arguably priceless solution in the evolution of your organizations System z Mainframe server journey from ESCON, if not Bus & Tag to FICON.  Perhaps the Prizm solution is one of these unsung products?  Therefore, the next time you’re reviewing the virtual tape market place, why wouldn’t you seriously consider Optica Technologies, given their rich heritage in FICON channel interoperability?  Given that IBM chose Optica Technologies as their strategic partner for ESCON to FICON migration, seemingly even IBM might have thought “nobody gets fired for choosing…”!

The IBM Mainframe – 50 Years & Counting

On 7 April 1964 IBM announced the System/360, which is now recognized as the first IBM Mainframe computer system.  IBM Board Chairman Thomas J. Watson Jr. called the event the most important product announcement in the company’s history.  At a press conference at the IBM Poughkeepsie facilities, Mr. Watson said:

“System/360 represents a sharp departure from concepts of the past in designing and building computers. It is the product of an international effort in IBM’s laboratories and plants and is the first time IBM has redesigned the basic internal architecture of its computers in a decade. The result will be more computer productivity at lower cost than ever before. This is the beginning of a new generation, not only of computers, but of their application in business, science and government.”

More than 100,000 businessmen in 165 American cities today attended meetings at which System/360 was announced.  50 years later, I wonder whether there are 100,000 people that work with the IBM Mainframe in The USA and maybe globally…

During this 50 year evolution, the IBM Mainframe has seen opinion polarize, sometimes from the same person:

  • In March 1991, Stewart Alsop stated “I predict that the last mainframe will be unplugged on March 15, 1996.”
  • In February 2002, Stewart Alsop stated “It’s clear that corporate customers still like to have centrally controlled, very predictable, reliable computing systems, exactly the kind of systems that IBM specializes in.”

Obviously the IBM Mainframe server is still here and just like in 1964, in the early 1990’s it did evolve into just another server on the distributed network and the use of routers, incorporating POSIX compliance and so on…

As we all know, the IBM Mainframe has always evolved, continues to evolve and in theory, and often in real-life, can run any workload.

Let’s reprise some of the notable IBM Mainframe models and associated functions since April 1964:

Family Name Announced Notable Function Introduction
S/360 April 1964 24-bit addressing (32-bit architecture)
S/360 August 1965 Virtual storage
S/360 January 1968 High speed cache
S/370 June 1970 Disk & printer support
S/370 August 1972 Virtual storage & multi-processor support
S/370 XA June 1983 Extended storage 24-bit/31-bit addressing
S/390 ESA September 1990 ESA & OS/390 operating systems
zSeries (zArchitecture) October 2000 z operating systems, 24/31/64-bit   addressing supported concurrently
zSeries z9 EC July 2005 zIIP specialty engine
zSeries z10 EC February 2008 High capacity/performance (quad core CPU chip)
z196 (zEnterprise) July 2010 96-way core design & distributed systems integration (zBX)
zEC12 August 2012 Integrated platform for cloud computing, integrated OLTP & data warehousing

It’s interesting to note that the purchase price of an IBM mainframe is about the same, comparing 1964 to 2014, let’s say~$100,000.  Of course, you can’t compare the feeds and speeds of these machines, they’re exponentially different.  However, just as the S/360 in 1964 played a pivotal part in shaping data processing for that decade, subsequent evolutions of the IBM Mainframe follow in that tradition, lowering the cost of IT and simplifying business management.

I’m sure a lot of us have enjoyed our time working with the IBM Mainframe server and long may that be the case, for future generations of IT professionals.