A mainframe computer is a high-performance computing system that’s used to rapidly process large amounts of data in real time. Because they have the memory and processing power to handle billions of calculations, mainframes remain an essential part in many businesses’ operations. They can analyze massive volumes of healthcare patient data, manage billions of ATM transactions and bolster government agencies’ cybersecurity defenses, among other use cases.
Mainframe Definition
A mainframe is a powerful computer that processes lots of data and handles multiple computations at once. Known for their security and reliability, mainframes are typically used as enterprise data servers, capable of processing up to one trillion daily calculations.
What Is a Mainframe?
A mainframe, commonly referred to as a data server, is a high-performance computing system designed to rapidly process large amounts of data. Known for their high throughput and reliability, these refrigerator-sized machines are built with specialized hardware, extensive memory and hundreds of data processors that enable large-scale batch computing with efficient input-output connectivity, allowing them to process up to one trillion online calculations per day.
Mainframes commonly serve as central fixtures to large business operations, thanks to their ability to reliably process massive volumes of data in real time and host mission-critical applications.
“You’ll find them at the heart of operations where reliability can’t be compromised,” said Darian Shimy, a former head of engineering at Square and Weebly and founder of school-fundraising platform FutureFund. Whether it’s in banking, healthcare or government services, “their job is to keep the digital aspects of heavy-duty industries running smoothly.”
According to IBM, the primary manufacturer of mainframe hardware, 92 of the world’s top 100 banks rely on mainframes, which are also responsible for processing nearly all credit card transactions.
“Mainframes continue to be the technology backbone of the world’s economy,” Petra Goude, senior vice president of core enterprise and zCloud at mainframe modernization company Kyndryl, told Built In. Despite its age, the mainframe “remains the right platform for mission-critical workloads,” Goude said.
A Brief History of Mainframes
Around since the 1950s, mainframes earned their name from the large cabinets (main frames) in which they were originally stored. These earlier iterations weighed several tons and were used for scientific calculations and military applications. As tech evolved, many companies transitioned from mainframes to distributed computing alternatives and cloud-based networks. Mainframes remain a staple in IBM’s portfolio and those of other major players like BMC, Precisely, Compuware and CA Technologies.
Mainframes were a sort of “black box” that isolated data from other infrastructure systems, resulting in compatibility issues, Jacky Hofbauer, the president and chief security officer at mainframe-management software company Zetaly, told Built In. However, novel tools that permit the access, collection and sharing of mainframe data using APIs allow hybrid-cloud modernization to breathe new life into an old relic. As a result, more than two-thirds of the roughly 10,000 mainframes in use today now power Fortune 100 companies.
Mainframe Benefits
Mainframe computers are known for their high performance, reliability, scalability, security and centralization.
High Performance
Mainframes are designed to deliver exceptional performance, capable of processing large volumes of data and supporting intensive computing workloads. They feature powerful processors, large memory capacities and high-speed input-output (I/O) subsystems to ensure fast and efficient data processing.
Reliability
A mainframe’s reliability delivers continuous operation at minimal downtime. Built with redundant components and fault-tolerant designs, mainframes have advanced error detection and verification mechanisms that prevent system failures, ensuring uninterrupted service and a near guarantee to anytime database access.
Scalability
Mainframes can be built out to accommodate growing computing needs and increasing workloads. This is done by scaling vertically, where additional processors, memory and storage capacity are added; or scaling horizontally, where multiple mainframe systems are connected in a parallel configuration to increase processing power and capacity.
“Not only are [mainframes] capable of bearing considerable workloads,” Hofbauer said, “they are also highly scalable and can increase capacity without experiencing performance degradation.”
Security and Compliance
Mainframes are equipped with strong security features, including data encryption abilities, cryptographic cards, authentication mechanisms and AI and machine learning algorithms that root out cyber attacks. Businesses can tailor these services to meet specific industry regulations and compliance rules as well.
Centralization
Mainframes unify an organization’s data silos altogether in one place. Using a centralized approach, administrators can monitor, configure and manage system resources from a single point of control.
Mainframe Characteristics
Some of the key components that power mainframe computers include multiple CPUs, I/O channels and a physical storage space, among others.
Multiple Central Processing Units
At the core of a mainframe computer is the central processing unit (CPU), which is the hardware that executes calculations, functions and other operations. Mainframes often contain at least two CPUs to amplify their processing capabilities.
Input/Output Channels
Input/output channels transfer data from one mainframe component to another, keeping information organized and enabling communication throughout a mainframe. The number of I/O channels in mainframes can vary, but more advanced mainframes can have over 1,000 I/O channels to handle large volumes of data.
Storage System
Mainframes are outfitted with physical storage space, including hard drives. A storage system enables a mainframe computer to store massive volumes of data for future analysis and calculations.
Control Unit
The control unit serves as a human-computer interface, allowing personnel to interact with a mainframe by sending information, submitting commands and performing other actions. A control unit may take the form of hard drives, ports or physical buttons.
Controllers
Controllers manage communications between a mainframe and other computers. Because these components enable computers to connect to and exchange data with mainframes remotely, users can access mainframes without being onsite.
Multiple Operating Systems
An operating system (OS) is software that manages a mainframe’s components, including its processors, memory and files. Mainframes are able to host multiple operating systems, which function as if they’re running on separate computers. This expands the capabilities of mainframes and allows them to fulfill different user needs.
Motherboard
A motherboard is the primary circuit board that uses an electrical system to connect the various components of a mainframe computer. Through this system, different parts of a mainframe are able to communicate information with each other.
Clustering Technology
Clustering technology gives a mainframe the ability to connect with other mainframe computers, so they can act as a single system. By distributing large data sets among multiple mainframes, this system can complete even more calculations.
How Are Mainframes Used?
Mainframe computers are commonly used to process financial transactions, manage digital healthcare records, support government services and monitor supply chain data, among other applications.
Processing Transactions
Banks and financial institutions use mainframes to process transactions, manage accounts and execute trades. If you’ve ever made an ATM withdrawal or swiped a credit card, you’ve interacted with an in-network card-reading device that communicates information, such as account balances and transaction records, to and from a mainframe.
Managing Patient Information
Since health records have become digitized, mainframes serve as the central hub of HIPPA-compliant patient management systems and information exchange. While they provide secure storage of diagnostics and medical imaging, they also assist doctors in transferring encrypted patient records back and forth to ensure continuity of care.
Supporting Government Services
Governments rely on mainframes to host mission-critical applications and manage large volumes of data. These machines keep track of citizen records, process tax filings, administer social welfare programs and support national security.
Tracking Sales and Inventory
Point-of-sale systems, inventory tracking and customer relationship management platforms use mainframes to keep retail operations in sync. The same systems that digitally calculate totals and authorize payments at the register for a seamless shopping experience can also maintain real-time records of products as they move through the supply chain and keep track of loyalty program points using a database of customer profiles.
Handling Travel Requests and Updates
Airlines use mainframes to handle millions of reservation requests daily. On passenger-facing interfaces, they deliver real-time updates to flight schedules, seat assignments and pricing information, then process boarding passes, seat upgrades and any additional baggage handling requests at check in. For airport staff, these centralized platforms handle everything from flight planning and crew scheduling to aircraft maintenance.
Monitoring Supply Chain Data
Mainframes support a number of manufacturing processes. Similar to retail, these systems are equipped to manage inventory and supply chain logistics as well production planning, quality assurance and distribution. No matter the production line, a mainframe enables seamless data exchange and decision-making across a company.
Measuring Student Progress
In educational institutions, mainframes serve as a centralized platform that manages student records, administrative tasks, courses and online learning platforms. They are used to tally enrollment and grades as well as data analysis or simulation modeling in research labs and master organizers in library management.
How Do Mainframes Work?
Instead of working on one massive complex problem at a time like a supercomputer, mainframes handle high volumes of simple computations and small data. They do this with the help of specialized CPUs. These hardware components are the “brain” of the computer that houses the electrical circuitry necessary to interpret and process inputs, store memory and carry out instructions in order to run programs and deliver outputs.
Multiple CPUs are often housed together in a central processing complex, and work in tandem with additional processors called system assistance processors (SAPs), tasked with moving data through I/O channels between the mainframe and external, in-network devices. The I/O then computes an output based on the requested information, and reports it to the original source.
For example, when a user inserts their card into an ATM card reader, the device retrieves that user’s debit account information from a bank’s mainframe over a network. It simultaneously validates the user’s identity, checks the availability of funds, processes the withdrawal amount and updates the accounts accordingly.
Modern mainframe systems use redundant circuitry in order to achieve high fault tolerance and availability without a single point of failure, according to Craig Wilson, a global technology officer at mission-critical support service provider Top Gun Technology.
“If a fault is detected,” Wilson added, “the operation is retried or recovered using error correction routines.” It can also move the data to a twin power circuit to complete the computation.
Wilson said that an entry-level mainframe may have a single CPU node, known as “a drawer,” with a single I/O node, whereas higher-end models may feature multiple CPU and I/O nodes that trade off data and processing workloads. Take IBM’s latest iteration of its popular Z series, the IBM z16, for example, which features four CPUs and 12 I/O drawers for a multiframe model, and four CPUs with three I/O drawers for the single-frame standard model.
Examples of Mainframes
IBM Z series
IBM’s latest series introduces AI inferencing to the mainframe space. The z16 model features an IBM Telum microprocessor at its core and industry-first, on-chip integrated accelerators with generative AI that predicts and automates tasks, delivering unprecedented speed and scale at low latency. It can support up to 40 terabytes of memory, process 25 billion transactions per day and can even survive an 8.0-magnitude earthquake.
FUJITSU Server GS21
FUJITSU launched its GS21 series in 2018, featuring a super-scale and medium-to-large version of the server. The super-scale model can host up to 16 CPUs with 256 gigabytes of storage and a maximum of 256 channels. So while it’s a 20-percent upgrade in performance compared to previous iterations, the hardware required to run such a machine has reduced by 40 percent. The Japan-based company plans to discontinue mainframe sales by 2030, but will continue providing parts and maintenance support through 2035.
UNIVAC 9000 series
Now discontinued, the UNIVAC 9000s are a relic of the 1960s. The Sperry Rand series featured four generations of machines that were built with small-scale integrated circuits using DTL technology and plate-wire memory. They were sold as a “flexible tape and disk oriented computer system featuring multiprogramming, real time capabilities and versatile possibilities for data telecommunication.” As featured in Technikum29’s Living Museum, one 9400 model — originally used in a Cologne-based Industrial complex computer center, then repurposed and given to a school the following decade — is still operational today.
Frequently Asked Questions
What is a mainframe?
A mainframe is a high-performance computer that processes massive amounts of data and computations in real time. Known for their high-throughput and reliability, these systems are often employed by large organizations as enterprise servers and unified databases for large organizations.
Is a mainframe just a server?
Not exactly; While mainframes are often employed as servers, they are not limited to this function. Mainframes are defined by their hardware, while servers are defined by their software.
Are mainframes still used?
Yes, mainframes are still currently in use, and have undergone their own digital transformation with hybrid cloud modernization.
