A mainframe is a high-performance computer designed to manage large volumes of data and large-scale computing tasks. These systems are optimized to offer high availability, scalability, and security, making them essential in critical sectors such as banking, insurance, government, and logistics.

Although cloud computing and distributed systems have gained prominence, mainframes remain crucial for ensuring continuous processing of large workloads. This article explores what mainframes are, their key characteristics, some mainframe system examples, and how they compare to other architectures like supercomputers.

Technical definition and characteristics of mainframes

Technically, a mainframe is a centralized computing system with substantial processing power, memory capacity, and input/output bandwidth, designed to support critical applications and databases. It operates in environments where downtime is unacceptable, offering advanced workload management, virtualization, and backward compatibility with legacy applications.

Key characteristics of a mainframe

Below are the main characteristics that define a mainframe:

  • High processing capacity: capable of executing millions of instructions per second, making them ideal for resource-intensive applications.
  • Large memory and storage: equipped with extensive capacities to efficiently handle large volumes of data.
  • High bandwidth: able to transfer large amounts of data continuously and quickly.
  • Advanced workload management: optimizes resource allocation across multiple applications and users.
  • Large-scale virtualization: can run multiple virtual environments on a single physical hardware, enhancing efficiency.
  • Legacy system compatibility: supports legacy applications, allowing integration with modern technologies without the need for complete infrastructure overhauls.
  • Reliability and high availability designed to minimize downtime, ensuring business continuity without interruptions.

Why Are Mainframe Computers Still Important?

Mainframes remain vital for many large organizations due to their ability to manage massive data volumes and transactions reliably and securely. These systems serve as the backbone for critical business applications, especially in sectors like finance and government.

While cloud computing has gained popularity, mainframes offer unique advantages, such as strong disaster recovery capabilities and efficient processing of large workloads, making them indispensable for many industries.

Key reasons why mainframes remain relevant:

  • Handling large-scale workloads: designed to process vast amounts of data and transactions simultaneously, making them ideal for high-demand applications like financial transactions, inventory management, and scientific simulations.
  • Reliability and availability: known for exceptional reliability and high availability, minimizing downtime and ensuring business continuity.
  • Security: offering robust security features, making them suitable for managing sensitive data and transactions, especially in banking and public administration.
  • Scalability: can scale to meet increasing processing demands, allowing organizations to adapt without significant infrastructure changes.
  • Cost-effectiveness in high-performance environments: although their initial cost can be high, mainframes can be cost-effective for organizations with large-scale processing needs.
  • Legacy system compatibility: allow integration of new technologies without abandoning existing infrastructure, supporting legacy applications.
  • Continued relevance: despite the rise of cloud computing, mainframes remain critical in industries with high security and regulatory requirements, such as banking and government entities.

10 examples of mainframe systems

Mainframes come in various families and models, with IBM zSeries being one of the most iconic. Here are 10 examples of mainframe systems that have made a significant impact in the market:

  1. IBM z15, z16, z17: part of the IBM zSeries, supporting multiple operating systems like z/OS, z/VM, and Linux on Z.
  2. UNIVAC: one of the earliest mainframe systems, now obsolete.
  3. Bull GCOS: an older system primarily used in Europe.
  4. Hitachi High-End Servers: high-performance mainframes manufactured in Japan.
  5. IBM z13: an earlier version of the zSeries, known for efficient processing.
  6. IBM z14: a continuation of z13, with enhanced security and encryption features.
  7. Hewlett Packard NonStop: known for its fault-tolerant capabilities in high-availability environments.
  8. Fujitsu BS2000: mainframe system primarily used in telecommunications companies.
  9. Stratus ftServer: a mainframe designed for high-availability solutions.
  10. NEC SX-ACE: a supercomputer based on NEC’s mainframe architecture.

What are mainframe technologies?

Mainframe technologies include a set of hardware and software solutions designed to maximize performance, reliability, and scalability in enterprise environments. Some of the key technologies used in mainframes include:

  • z/OS: IBM’s flagship mainframe operating system, known for its stability and security.
  • CICS (Customer Information Control System): a high-volume transaction server.
  • DB2: a robust relational database management system widely used in large corporations.
  • RACF (Resource Access Control Facility): IBM’s security framework for access control and auditing.
  • JCL (Job Control Language): a scripting language used to run batch processes.
  • SMF (System Management Facility): a monitoring and logging tool for z/OS.

The role of mainframes in the modern enterprise

Despite being considered outdated by some, mainframes continue to evolve and play a key role in the digital transformation strategies of many companies. Modern mainframes are compatible with open standards, containers, AI, machine learning, and DevOps practices.

They are used for transaction processing, data analytics, and managing cloud-native workloads, often through APIs or microservices frameworks.

Mainframes are still important

Mainframes are not relics of the past. They are powerful, modern computing platforms designed for complex, large-scale, and high-security environments. Their processing capabilities, reliability, and scalability make them indispensable tools in industries that cannot afford downtime or data security failures.

Understanding what mainframes are and how they work is essential for IT professionals working in enterprise environments or managing critical infrastructure.