Recently, I was interviewed by Pcon (unfortunately the link points to an Hebrew only site) as part of debriefing on Legacy Systems.
Pcon is an Israeli company investigating IT topics by quoting professional articles and interviewing experts.
They publish the results of the investigations including practical recommendations.
This post is mainly about topics raised by me during the interview, but not included in the debriefing, which will be published.
What are Legacy Systems?
The term Legacy Systems refers to old application systems and/or veteran technologies still in use.
Usually, the term Legacy Systems is associated with:
1. Mainframe Hardware e.g. IBM System z and its Operating Systems or Proprietary Servers and Operating Systems such as HP Alpha and OpenVMS Operating System, IBM AS/400 and OS/400 Operating System.
2. Development and Production Environments, e.g. COBOL, Natural and DBMS systems such as Adabas and IDMS executing on Mainframes or Proprietary Servers infrastructure with proprietary Development and Production Environments.
3. Applications Systems developed more than ten years ago executing in the infrastructure environments cited above using the IDEs and DBMS Systems cited above.
It is true that often Infrastructure and Applications, cited above are Legacy Systems, however there are also Legacy Systems using other technologies such as Visual Basic version 6 or older, old Java technologies and old Windows Operating Systems or extincted UNIX Operating Systems.
In this post i limit the term Legacy Systems to IBM Mainframe systems.
Why investigating Legacy Systems?
The main reason is that these systems are used by many enterprises.
The systems are not only frequently used, they are used for Business critical Processes and Transactions and store and manipulate critical Data.
The second reason is that these systems are no longer Mainstream, as far as new systems buying or building is concerned.
Young people knowledge of theses systems technologies, architectures and concepts is usually limited.
The young generation is not ready to learn about these systems and prefer newer concepts and technologies.
This is the third reason to investigate: limited availability of Legacy Systems skilled professional, which raise the question: why not migrating to other environments before lack of skilled professionals availability will be a crucial problem?
So why not migrating to other environments?
For some enterprises, the question above is a good question and the answer is positive they should migrate from Mainframes to other platform.
Other enterprises have good arguments for avoiding migration.
The following list depict some reasons for not migrating:
1. If it is not broken do not fix it.
2. Replacing Legacy Systems by other systems is expensive and will take long time.
3. Probably, some of the team members should be replaced because they will not make the transition to a new system, new infrastructure and new methods.
The down side is losing their experience and their knowledge (especially non-technical knowledge of the Business, the Organizational Culture and the practices.).
Is it possible to identify those who should migrate and those who should not?
Yes it is. Size Matters. Usually Small Enterprises are better migration candidates than Large Enterprises.
Small Enterprises will not face Scalability issues and Performance issues.
They also pay more relatively to their size, because Mainframe Hardware and Software prices are skewed in favour of Large Enterprises.
They will not have to hire a large number of people to support large number of Servers as Large Enterprises will have to.
Large Enterprises usually operates more Application Systems and their Application Systems are more complex, so the migration will be prone to more errors and failures and will cost more.
Another discriminating factor is the Operating System.
Large Enterprises use IBM's Mainframe flagship Operating System z/OS. Some Small Enterprises use the declining z/VSE Operating System.
Some of the Independent Software Vendors stop support or new versions development of VSE software products. Other minimized their development efforts and current versions support.
The future seems even gloomier because the deteriorating VSE installation base.
Is IaaS a Game Changing Technology?
IaaS looks like a game changing. Users of Operating Systems such as Windows and Linux can lower their TCO by moving part of the Data Center or the whole Data Center to the Public Cloud. Mainframe users can not.
Most Large Enterprise will not move their Core Systems to a Public Cloud in the following two or three years, but SMBs are candidates for moving soon their systems to the Public Cloud.
This trend could be another catalyst for Small Mainframe sites to migrate to Windows, Linux or UNIX.
However, IaaS also change another prevailed concept of running Infrastructure and Systems within the Enterprise boundaries, i.e. its Data Center or Data Centers.
The Public Cloud age, change this concept: You no longer need to own and maintain the physical infrastructure (very similar to the concept of not placing Electricity Generators in every house).
Lower TCO based on getting rid from Data Center Servers is a challenge for Small Mainframe installations, but it is also an opportunity to save the migration efforts, by moving their Application Systems
to a larger Mainframe user premises and lowering the TCO as well. Larger Enterprises can assign Virtual Mainframe Servers to Smaller Enterprises.
Related Posts in my Blog
Mainframe and the Dinosauraus Myth Revisited
IBM z/Enterprise First Take: Data Center in a Box or Cloud Computing
Vendors Survival: Will Software AG Survive until 2019?
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