What is a Mainframe? Features, Importance, and Examples

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Written By Nidhi Sharma

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A mainframe can be described as a powerful, large-sized computer that is used to perform complex data processing tasks.

▸A mainframe connects to many end clients and allows users to access multiple apps simultaneously.

▸It can connect simultaneously to multiple end clients so that multiple users can access different processes and applications on the mainframe simultaneously without affecting performance or security.

This article will explain how mainframes function and discuss their importance in today's age of cloud computing.

What is a Mainframe?

Large enterprises use a mainframe computer for mission-critical applications.

▸This includes processing large amounts of data to perform activities such as censuses, industry, consumer analytics, enterprise resource plan, or large transaction processing.

▸Mainframes today are smaller than those of the "Big Iron", the giants of the past. A 19-inch rack might allow the most recent mainframe to cohabit with other systems in the data center.

▸Modern mainframes can also be called data servers, even though they aren't identical to mainframes.

▸They are designed to perform up to 1 trillion online transactions per day with the highest levels of safety and dependability.

Mainframes are often used in applications that require high availability. This is because they are expensive and sometimes difficult to down.

Some important features include:

▸Mainframes can increase or modify system capacity at will, without interfering with system operations. Mainframes offer sophistication and expertise that are unmatched in server solutions due to their precision and granularity.

▸Modern mainframes like the IBM zSeries offer two virtualization levels, logical partitions or virtual machines. Mainframe users often have two mainframes: one in their primary data center and one in their backup. These machines can be active, partially active, or in standby mode in case of an emergency.

▸If the demand for these tasks is high or the machine's resources are exhausted, testing, development, training, and production workloads may all be done on one system. The configuration of two mainframes can allow for continuous business service and prevent interruptions both planned or unscheduled.

▸Mainframes are designed to handle large amounts of input and output (I/O) and prioritize throughput. Since the 1950s mainframe architectures have had auxiliary hardware that can control I/O devices. This allows the CPU to concentrate on high-speed memories.

▸Mainframes are often used to manage large databases and files. It is not uncommon to find records with gigabyte-to-terabyte storage. Mainframes can access large amounts of online data quickly and often have a higher capacity than a regular computer.

What does a Mainframe do?

Three essential tasks are performed by mainframes. Let's take a look at each.

Function as a data warehouse orchestration software: Each computer has a hard disk for long-term storage. However, mainframe systems store all data inside their applications. Remote users who have linked terminals can log in to the mainframe. This grants them access to all their files and applications.

Enforce access and authentication permissions: Storing software and data on one mainframe system can increase efficiency but also pose a threat to data security. Administrators have access to programs and data in mainframe systems. Administrators can also control access and determine who has it. Mainframes can be used as firewalls to protect against intruder attacks.

Allocate processor time and resources: Mainframe systems can divide a limited amount of processing power between all concurrently logged-in users. The mainframe can determine which priority types correspond to which users. These priorities can be set by the mainframe administrator.

The Features of a Mainframe Computer

These are the features of a mainframe computer.

1. Two Processors are Required

Mainframe computers have two types of processors: the primary processor and the system assistance processor (SAP).

This latter does not process data but rather transfers it as fast as possible from one place to the next. A CPU can have seven to ten cores that are specifically designed and built for higher throughput.

2. Multiple Input/Output Cards (I/O)

Because they are intended for redundancy, each mainframe could contain up to 160 I/O cards. This means that, if one card fails to function properly, other cards will assume their duties until it is repaired.

3. Storage Capacity is High

These systems are equipped with enormous storage capacities, which allow them to process large amounts of data quickly. It can store large amounts of data and interpret them according to the user's specifications.

The system will provide precise results with zero data errors after data processing.

4. Performance Based on RAS

Mainframe applications are designed with reliability and availability (RAS), in mind. This distinguishes them from other systems.

These computers make data processing simple and allow businesses to use the system's scalability feature to store varying amounts of data. All of these apps are supported by the CPUs in the system.

5. There are No Interruptions to the Operation

Workloads are spread across processors to ensure that software updates on mainframes do not slow down productivity. Other cases might make it prohibitively costly for the company to pause the system.

If the organization is a financial institution it could also endanger national security by not being able to process applications. Mainframes are designed to keep important systems available at all times.

6. Multiple Operating Systems can be Installed on the Same Machine

Multi-operating systems can be hosted on one mainframe. It is common to use Linux alongside z/OS on a single mainframe. z/VM and z/VSE are the most popular mainframe operating systems, as well as z/OS.

7. Throughput-Driven Fault-Tolerant Computing

The system receives a large amount of input and output data. Mainframes need to be able to manage all this data, applications and processes efficiently.

Mainframes are not affected by the amount of data transferred to or from a particular system.

Moreover, the mainframe prevents errors from occurring when moving large amounts of data within its database. This is called fault-tolerant computing.

8. Clustering Technology

Clustering technologies that are close to each other (called Parallel Sysplex within an IBM environment) can be supported by Mainframe systems.

This allows you to operate up to 32 machines in a unified system configuration. Even if the system crashes, all work on the next live system will continue seamlessly with no performance loss.

9. Centralization of Computing Processes

The centralization of computing tasks is achieved by the mainframe system. This means that all processing takes place in the mainframe's processing area, and results are displayed on the client's desktop monitor.

While the mainframe is running in the background, the user can interact with an app or utility on the desktop.

10. A Move Towards Flexibility

However, today, the gap between distributed and centralized computing is rapidly shrinking.

Mainframes are often combined with simpler servers in clusters, allowing them to be used in a variety of topologies.

Modern mainframe hardware, and software assets, such as processors, storage, and device interfaces, can be reconfigured dynamically, allowing programs to continue to run. This highlights the flexible and changing nature of modern mainframes.

11. Servers Offer Performance Advantages

It is important to understand the properties of mainframes and their inherent differences. Although they are often interchangeable, mainframes are distinct from servers in these ways:

Size: A standard commodity server is physically smaller than any mainframe. This is due to the size of the mainframes. Mainframe computers now have the size of a refrigerator. A server tray of the same dimensions might hold 12 low-cost servers. Due to its computing hardware resources, mainframes will be heavier than traditional servers.

Throughput: A standard server can process around 300 transactions per second. This translates into approximately 26 million transactions every day. Although this is a significant number, it pales in comparison to the trillions of transactions a mainframe can handle. IBM claims Z13 mainframes are capable of processing 2.5 billion transactions per day.

Versatility: It is impossible to migrate mainframe workloads from commodity servers. You can transfer tasks to a mainframe which would normally be done on a commodity host. This means that mainframes can offer both the best and worst of both worlds. Mainframes allow users to access mission-critical applications and manage server workloads using commodity hardware.

The Top 6 Benefits of Mainframes

Mainframe computers are an integral part of many of the top companies around the globe, including Fortune 1000 corporations.

Despite the advances in computing technology, mainframes are still important in banking, finance, administration, insurance, utilities, and other private and public sector sectors.

1. Cloud-Ready, Scalable Infrastructure

Mainframes can create a variety of highly secure virtualized environments for cloud deployment.

This includes the z/VM operating systems, blade servers, hypervisors as well as logical parts (LPARs).

Mainframes can support millions of users at a faster speed and are the best platform to do big data analytics, data management, and create web apps. The technology is therefore highly adaptable.

2. Ensure Compliance and Security

Mainframes can support industry standards and compliance regulations and best practices through data encryption, role segregation, and secure communication systems.

It allows for enterprise-wide visibility, as well as a high level of security transparency. This allows for improved control. Private clouds that are built on mainframes can reduce security risks associated with public cloud services using open networks.

3. Consolidate and Simplify the Migration of Workloads

It is easy to transfer dispersed tasks from one system to another. This reduces the number of distributed systems that need to be managed.

Once your virtual environment is optimized, it's easy to consolidate different tasks on the mainframe and maintain the required separation between systems. This reduces license costs that dispersed systems might incur.

4. Lower the Cost of Ownership

Mainframe computers have the greatest advantage of being extremely long-lasting. They have an average life expectancy of more than ten years.

Mainframe computers are usually trouble-free until that point. Consumers can then choose to replace or upgrade the unit after the unit has reached its average lifespan.

There is also a limit at which server growth becomes more costly than mainframe workloads.

Security Research Management opens a new window. It was found that the total cost of ownership (TCO) for a private cloud created on IBM zEnterprise Systems was 76% less than for a public cloud provided by a third-party service provider.

5. Assure Compatibility Between Generations

Mainframe computers can run a wide variety of software and hardware. A mainframe can support almost any software regardless of its OS version.

The system can still run legacy programs even after an update.

Mainframe computers do not limit the number of concurrent operating systems. Multiple operating systems can be used to enhance the overall system performance.

6. Compatible With Blockchain Technology

Blockchain is among the most exciting new applications, for which mainframes make a great match. The mainframe is a better choice than x86 servers for speed, transaction throughput, security, and scalability.

Its security advantage is also significant. Blockchain is based on transaction data that is stored in immutable blocks and cannot be altered after they are assembled. Due to their greater computing power, mainframes can provide 100% encryption without impacting performance.

While mainframes are still essential for the reasons stated above, they have some drawbacks. The following are some things to consider before setting up a mainframe system.

Complex implementation: Because of its physical components, setting up a mainframe computer can be more difficult than installing a regular computer.

High initial cost: A mainframe's initial outlay is significantly higher than that of standard servers or the cloud.

Complex maintenance: IT professionals cannot manage mainframe computers. This requires operations management, and in particular system debugging.

Environment conditions: Mainframes are subject to additional environmental restrictions, such as maintaining temperature and humidity.

Examples of Mainframes

Although mainframe-like computing methods are common, actual mainframe computers are rare to find in circulation (apart from IBM models). Here are some notable examples of mainframes.

1. IBM Z

IBM calls all its z/Architecture mainframes the IBM Z. With the launch of a new line of products in July 2017, IBM z Systems was rebranded to be called IBM Z. The current IBM Z mainframe line includes the latest model, the IBM z16. It also includes z15, z14, and z13.

The IBM Z family maintains 100% backward compatibility. Modern systems are the direct descendants of System/360, which was first introduced in 1964. The newest IBM Z system, half a century later is compatible with all software designed for older systems.

2. FUJITSU Server GS21

FUJITSU Server GS21 can be used for mission-critical corporate or social infrastructure systems that need to operate 24x7. Fujitsu has continuously improved mainframe processing speed, functionality, and standards over 50 years to meet new demands.

The FUJITSU Server GS21 is capable of managing large amounts of data and can ensure high availability at a lower total cost of ownership. Fujitsu announced that it will stop selling mainframes by 2030 and will cease maintenance & support in 2035.

3. UNIVAC 9400

The 9400 was designed for small- and medium-sized companies that needed simple system expansion. A UNIVAC 9400 mainframe, which was built in 1960, was used to run the computer center at a Cologne industrial complex. The system was eventually replaced with new technology and hardware and donated to a school near Cologne. It was then moved to the technikum29 in Cologne, Germany, where it is still functional today.


Mainframes have the greatest advantage of being able to run critical applications on a large scale.

While not every business will require a mainframe computer, those who do rely on them for their business-critical processes are dependent heavily upon mainframe computers.

Mainframes are essential for banks and large financial service providers to ensure that transactional processes run smoothly without interruptions or downtime.

That's all in this blog.  I hope you find it helpful and insightful. You can suggest more in the comment section below or can contact our expert team. Keep learning always as there is a saying that " The one who reads always leads." 🤗

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