February 17, 2020

[Exploring Mainframe] What makes mainframe faster, more stable, reliable, and secure?

A lot of people say mainframe (and Cobol, DB2, etc) is dead and will go away.  Some say it will be around longer.  Both sides agree that mainframe is still in use because it's faster, stable, reliable, and more secure. 

Here, I'm putting down some notes on mainframe as I googling/reading.  This is not an attempt to advocate/favor mainframe.  It's just a note on what I learned/learning about it.  And to answer my own question: Why is it faster, more stable, reliable, and secure -- compare to cloud?  I asked around this questions, but no one seemed to be able to give real reasons.

Scalability, Performance, Reliability, Cost

  • hundreds of thousands of transactions per second
  • Can virtualize hundreds or thousands of servers
  • Vertically and horizontally scalable.
  • Lower TCO (depends on the case and how you look at it though)
  • Faster I/O


  • Security is built into the OS and cryptography is hardware accelerated.
  • Large volume of transactions with hardware accelerated encryption/decryption.
  • Better Access Control model 

Maintenance, Availability

  • maintaining is simpler compare to cloud's 100's-1000's servers for H/W, OS, patches, upgrades
  • managing users is simpler
  • continual uptime - s/w, h/w upgrades without any downtime.
    • Architecture: separate memory partitions for OS, software-subsystem components, middleware, applications. (ESA: Enterprise Systems Architecture)

Other Reasons/Notes

  • If data is on mainframe, running analytics where data resides is faster.
  • Can be integrated with other modern platforms
  • Does 68% of IT work, but with only 6% of budget.


Mainframe is more...
  • Faster: transaction wise it's much faster due to its architecture.
  • Reliable: no downtime, no "internet" connection. architecture is the reason again.
  • Secure: access control model, hardware accelerated encryption. H/W difference.
  • TOC: this is per case.  It's a false belief that mainframe is always a lot more expensive.
The architecture of mainframe makes it better for some of IT needs.  Cloud is more elastic - of course, because of that nature, everything has to be built -- a lot more options, that means a lot more risk, unreliable, less matured.  The point is, both are needed, for different purposes.


Most of articles listed here favor mainframe, of course -- since I searched for benefits and advantage of mainframe.  However, they have good points.

Interesting Facts

The z14 is based on a 10-core processor running at 5.2 GHz. The z14 system can have 240 Processing Unit cores, 32 TB of memory (RAIM) and is estimated to be able to execute over 140 Billion instructions per second. The z14 processor has a variety of hardware assisted cryptography features that focus on pervasive data encryption. The z14 supports up to 320 concurrent 16 Gbps fiber-optic I/O connections and a new I/O link called IBM zHyperLink Express that is designed to support up to 32 ports with link data rates of up to eight gigabytes per second (equivalent to 64 gigabits per second each). [SG24-8451-00 Redbooks IBM z14 Technical Guide] https://www.redbooks.ibm.com/Redbooks.nsf/RedpieceAbstracts/sg248451.html?Open

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