Mainframe Technology: What You Need to Know
Mainframes might not get as much attention as newer technologies, but they’re still doing a lot of the heavy lifting behind the scenes in major industries. Banks, insurance companies, hospitals, government agencies—they all count on mainframes to keep their systems running smoothly. Even with the rise of cloud computing, mainframes haven’t gone away. In fact, they’ve evolved to work with newer tools and platforms.
What Is a Mainframe?
A mainframe is a computer system that large enterprises utilize to rapidly and securely perform a huge number of transactions. These systems are designed to perform activities requiring continuous speed, stability, and data security. Some mainframes are capable of managing up to one trillion secure web transactions per day.
They come with large amounts of memory and multiple processors, allowing them to perform billions of basic operations quickly. Mainframes are commonly used for running commercial databases, processing transactions, and supporting applications that need constant availability and strong security.
Although some people assume mainframes are outdated due to the rise of cloud computing and internet-based systems, they are still widely used. Modern mainframes have been updated over time and remain an important part of IT systems for many large companies.
IBM reports that 45 of the top 50 global banks, 4 of the 5 largest airlines, 7 of the top 10 global retailers, and 67 of the Fortune 100 companies use mainframes regularly. Research from the IBM Institute for Business Value shows that around 70% of the world’s production IT workloads run on mainframes, and 70% of business leaders say that mainframe applications are important to their overall strategy.
The term “mainframe” originally described the large physical frame that held the central processing unit in early computing systems. These early systems acted as central hubs, connecting multiple terminals within an organization. Over time, as hardware became smaller and processing improved, mainframes moved from centralized setups to more flexible models. Today, they are often called enterprise or data servers and are still used to manage and store important business data.
The Transformation of Mainframe Computers: From Dominance to Niche Applications
From the 1950s to the early 2000s, many companies developed mainframe computers, but the number of manufacturers dwindled as cloud computing gained momentum. IBM became the dominating player, first with the 700/7000 series and then with the breakthrough 360 series, which laid the groundwork for its current zSeries mainframes.
International firms like Siemens and Telefunken (Germany), ICL (UK), and Fujitsu and Hitachi (Japan) all contributed significantly to mainframe development. During the Cold War, the Soviet Union and Warsaw Pact countries created virtually identical clones of IBM mainframes.
By the 1980s, more advanced minicomputers began handling some of the less demanding tasks previously managed by mainframes. Microcomputer-based servers grew more inexpensive over time, providing users with greater independence, particularly as IT policies changed toward decentralized control.
The development of personal computers hastened this tendency by eventually replacing conventional terminals used to access mainframes. As demand for mainframes fell, they were more relegated to areas like as government and banking, where their unrivaled dependability and processing capacity remained critical.
In April 2022, IBM introduced the z16 mainframe, which contained a built-in AI accelerator and a revamped CPU, demonstrating that mainframe technology is evolving and remaining relevant in current contexts.
Key Functions of Mainframe Computers
Mainframes are designed to provide three major functions, making them essential in large-scale computer systems. Let’s go further into what they do.
Centralized Data Management and Access
Unlike standard computers that store data locally on hard drives, mainframes function as centralized data orchestration systems. They host applications and datasets within a single system, allowing remote users with terminal access to retrieve files and run applications from one secure location.
Enforcing Security and Access Control
Mainframes improve data security by centralizing control. Administrators can control access privileges so that only authorized users can interact with certain applications or data. This makes mainframes an effective alternative for enterprises that require stringent authentication measures and security against unwanted access.
Resource and Process Allocation
Mainframes are designed to support a large number of concurrent users. They efficiently divide processing power and system resources according to user roles and priority levels. Administrators can configure these priorities to ensure that high-priority activities receive the resources they demand while maintaining overall system performance.
Key Features of Mainframe Computers
Mainframe computers are intended to handle high-volume, mission-critical tasks. Their architecture and capabilities much outperform traditional servers in terms of performance, reliability, and flexibility. Here are the essential characteristics of the current mainframes:
Dual Processor Architecture
Mainframes include both primary processors and System Assist Processors (SAPs). While primary CPUs handle computing tasks, SAPs accelerate data transfers. Each CPU may have 7 to 10 custom-built cores, supporting massive throughput and multitasking.
Redundant I/O Card Support
Mainframes may accommodate up to 160 input/output (I/O) cards to provide redundancy. If one card fails, others take over effortlessly, reducing interruption and ensuring system stability.
Massive Storage Capacity
Because of their enormous storage capacity, mainframe computers can successfully process and analyze vast datasets. They deliver accurate, error-free data processing, which is vital for enterprises that require accuracy.
RAS-Centric Architecture
All applications and system components are based on RAS (reliability, availability, and serviceability). This guarantees constant uptime, simple issue diagnostics, and uninterrupted performance for enterprise operations.
Continuous Operation with No Downtime
Software upgrades and hardware modifications are conducted without bringing the system down. Workloads are dynamically allocated to avoid service disruptions, which is crucial in areas such as banking, where downtime can have serious effects.
Multiple Operating Systems
A single mainframe can run multiple OS environments simultaneously. It’s common to run z/OS alongside Linux, as well as other operating systems like z/VM, z/VSE, and z/TPF—all within the same physical machine.
High Throughput and Fault Tolerance
Mainframes process large volumes of input and output without performance degradation. Their fault-tolerant design ensures that even during heavy data movement, operations remain accurate and reliable.
Advanced Clustering Technology
Using IBM’s Parallel Sysplex or similar technologies, up to 32 mainframe systems can be clustered to function as one. If one machine fails, others continue the workload with no loss in performance or availability.
Centralized Processing Model
Mainframes centralize computing tasks, managing data and applications on the backend while users access them via client interfaces. This model improves control, consistency, and system efficiency.
Flexible System Configuration
Modern mainframes can be dynamically reconfigured without halting workloads. They also integrate with distributed systems and server clusters, bridging centralized and decentralized environments.
Clear Advantages Over Commodity Servers
- Size: While mainframes are large, they are comparable in size to a refrigerator. A similar footprint of commodity servers may house 12 low-cost machines, but with far less computing power;
- Throughput: A standard server may handle 300 transactions per second—about 26 million per day. In contrast, IBM’s z13 mainframe can process up to 2.5 billion transactions daily;
- Versatility: Unlike commodity servers, mainframes can take on server-class workloads while also supporting mission-critical applications that cannot run elsewhere.
How Modern Mainframes Operate
Early mainframes, such as the IBM S/360, relied on a single central processing unit (CPU). In contrast, today’s mainframes use a central processor complex (CPC) made up of multiple specialized processors, each optimized for specific tasks.
Modern mainframes are equipped with dedicated cards for networking, encryption, storage, and data compression—each with its own processors and memory. System Assist Processors (SAPs) accelerate data transfers between the operating system and input/output devices. Additional processors handle Linux, Java, and other workloads, enabling the system to maintain high performance and maximize resource usage around the clock.
With this advanced architecture, modern mainframes support critical operations for sectors like finance, healthcare, government, and utilities, handling everything from massive data processing to high-volume transactions. They’re also built to integrate with modern technologies, including cloud infrastructure, big data, analytics, AI, and even quantum computing, through specialized extensions and integration layers.
6 Reasons Why Mainframes Still Matter
Many of the world’s biggest corporations, including Fortune 1000 companies, continue to rely on mainframes as vital components of their IT infrastructure. Despite advances in alternative computer models, mainframes remain vital in areas such as banking, healthcare, insurance, utilities, government, and more.
Support for Scalable, Cloud-Ready Infrastructure
Mainframes provide a secure and scalable foundation for cloud deployments. They enable virtualization by utilizing technologies like as logical partitions (LPARs), hypervisors, blade servers, and the z/VM operating system. This arrangement allows businesses to efficiently handle millions of users and large volumes of data, making mainframes an ideal platform for big data, analytics, and corporate applications.
Strong Compliance and Security Capabilities
Data encryption, role-based access control, privileged user monitoring, and extensive audit reporting are among the security measures integrated into mainframes that fulfill industry standards and regulatory requirements. These technologies provide enterprise-wide insight and enable the secure deployment of private cloud environments, reducing exposure to the hazards commonly associated with public cloud solutions.
Efficient Workload Consolidation and Migration
Mainframes make it easier to consolidate and handle duties that were previously scattered across several systems. This decreases system complexity, simplifies management, and lowers license fees. Virtual environments on mainframes can be configured to accommodate diverse workloads while keeping programs and users separate.
Lower Total Cost of Ownership
Mainframes are known for their long operational lifespan, often exceeding ten years with minimal issues. Over time, the cost of running multiple servers can surpass that of operating a mainframe. Studies show that the TCO for a private cloud built on IBM zEnterprise systems can be up to 76% lower over three years compared to third-party public cloud services.
Long-Term Compatibility and Flexibility
Mainframes are designed to accommodate a wide range of software and hardware, including several OS versions. Legacy programs continue to work after system updates, and different operating systems can run concurrently on a single mainframe, increasing system performance and flexibility.
Support for Blockchain Integration
Mainframes are ideal for blockchain applications, since they provide rapid reaction times, high transaction throughput, scalability, and superior security. Their ability to handle complete data encryption without performance reduction makes them a better host for blockchain systems than regular x86 servers.
Additional Considerations
While mainframes offer many advantages, there are also some challenges to consider:
- Complex Installation: Setting up a mainframe system is more demanding than deploying standard servers;
- High Initial Cost: The upfront investment for mainframes is significantly higher than traditional server or cloud options;
- Specialized Maintenance: Maintenance requires trained personnel with experience in system operations and debugging;
- Environmental Requirements: Mainframes must be maintained in controlled environments, with attention to temperature and humidity.
Notable Examples of Mainframe Computers
While many computing systems adopt mainframe-like methods, true mainframe computers are relatively rare today, with IBM being the most prominent manufacturer. Below are some key examples of actual mainframe systems:
IBM Z Series
IBM Z is the latest generation of IBM mainframes built on z/Architecture. Rebranded in 2017, the line includes models like the z16, z15, z14, and earlier systems such as the z13 and zEnterprise. A key feature of IBM Z is its backward compatibility—programs written for the 1964 System/360 can still run today, protecting long-term software investments.
FUJITSU Server GS21
Fujitsu’s GS21 mainframe is built for critical workloads that demand high availability and reliability. With over five decades of development, it offers strong performance and low ownership costs. Fujitsu plans to stop selling mainframes by 2030, with support ending in 2035.
UNIVAC 9400
Launched in the 1960s, the UNIVAC 9400 was aimed at mid-sized businesses. One unit, once used in Cologne, Germany, now resides in the technikum29 computer museum—still in working condition after decades of service.
Who Uses Mainframe Computers?
According to a report by Allied Market Research, the global mainframe market was valued at USD 2.9 billion in 2022 and is expected to grow to USD 5.6 billion by 2032, with a compound annual growth rate (CAGR) of 7.3%.
Mainframes are still essential to the basic functions of many significant industries. The following industries mostly depend on mainframe systems:
Financial Institutions
Mainframes are used by banks and other financial organizations to handle large-volume operations, including processing credit cards, making withdrawals from ATMs, and conducting internet banking. These systems provide the security, scalability, and performance required to maintain safe and efficient operations. The speed and strong security provided by mainframes may be used by even more recent technology, such as blockchain.
Healthcare Providers
Major insurance companies and healthcare organizations rely on mainframes to manage large volumes of sensitive data, such as patient records, billing information, and personally identifiable information (PII). The robust security features of mainframes help ensure compliance with data protection standards.
Government Agencies
Various government departments depend on mainframes to deliver secure and reliable public services. From national security to law enforcement, mainframes provide high performance, system resilience, and advanced cybersecurity. Modern systems also incorporate AI capabilities to enhance data analysis and threat detection.
Retail Industry
Large online retailers use mainframes to manage high transaction volumes across multiple platforms, including web and mobile devices. Mainframes support real-time inventory updates, order processing, and customer data management with the reliability needed for continuous operations.
Conclusion
Mainframes remain an essential part of IT operations in organizations that require high reliability, strong security, and the ability to process large volumes of data. They are actively used in sectors such as finance, healthcare, retail, and government, where performance and availability cannot be compromised. Despite changes in technology, mainframes continue to adapt and integrate with modern systems. Their role in supporting enterprise workloads remains consistent, making them a relevant and reliable solution for long-term infrastructure planning.
