What Is a Mainframe? Features, Importance, and Examples

What Is a Mainframe? Features, Importance, and Examples

A mainframe is defined as a large, powerful computer typically used for complex calculations and data processing tasks. It can connect to multiple end clients simultaneously so that several users can access different applications and processes running on the mainframe concurrently without impacting performance or security. This article explains how mainframes work and discusses their importance, even in the age of cloud computing.

What Is a Mainframe?

A mainframe computer, often colloquially known as a big iron or mainframe, is typically used by large enterprises for mission-critical applications. This involves processing massive amounts of data for activities like censuses, industry and consumer analytics, enterprise resource planning, or large transaction processing. Today’s mainframes are far smaller than the “Big Iron” giants of the past. The most recent mainframe might cohabit with various systems in the data center using a 19-inch rack.

Modern mainframes are also referred to as data servers (even though servers are not identical to mainframes). This is because they are meant to execute up to 1 trillion daily online transactions with the highest degrees of safety and dependability. In practice, mainframes have a high degree of availability, as they are frequently used for applications in which downtimes would be expensive and, at times, challenging for an organization. 

Reliability, availability, and serviceability or RAS, is the distinguishing feature of mainframe computers. Other primary features include:

Evolution of mainframe computers

From the 1950s to the early twenty-first century, many manufacturers and their successors built mainframe computers, with the number steadily decreasing as the cloud matured. The 700/7000 series and subsequent production of the 360 series mainframes led to IBM’s unquestionable ascendancy. Their present zSeries mainframe computers have continued to advance from the later design.

Germany’s Siemens and Telefunken, U.K.’s ICL, and Japan’s Fujitsu and Hitachi were notable foreign manufacturers. During the Cold War, the Soviet Union and Warsaw Pact nations produced indistinguishable clones of IBM mainframes.

In the 1980s, minicomputer-led systems became increasingly advanced and were able to replace the lower portions of the mainframes. And over the next few decades, businesses discovered that servers built on microcomputer designs could be implemented for a fraction of the purchase cost and offer local users far more autonomy over their own systems, given the then-current IT policies and practices. 

Personal computers progressively replaced the terminals used for communicating with mainframe systems. As a result, demand decreased, and future mainframe installations were mainly limited to the financial sector and the government.

IBM unveiled their most recent mainframe system, the IBM z16, in April 2022, which had an on-chip artificial intelligence (AI) accelerator and a new CPU, giving mainframes a fresh lease on life.

What do mainframes do?

Mainframes carry out three essential tasks. Let’s understand each one in detail. 

  • Act as a data warehouse orchestration system: Every computer has a hard drive for long-term data storage, but mainframe systems store the entire data as an application inside themselves. When remote users with linked terminals attempt to log in, the mainframe grants all remote terminals access to their files and applications.
  • Help enforce authentication and access permissions: Storing data and software files on a single mainframe system may increase efficiency, but it may also jeopardize data security. In mainframe systems, administrators have control over programs and data. They can also determine the individuals who have access. Therefore, mainframes may serve as firewalls against intruder attacks.
  • Allocate processor time and resources: Mainframe systems can divide a finite amount of processing power among all concurrently logged-in users. Consequently, the mainframe determines which types of priority correlate to which types of users. The mainframe administrator has the authority to determine these priorities and allot processor resources.

Features of a Mainframe Computer 

1. Presence of two processors

There are two types of processors in mainframe computers: the primary processor and the system assistance processor, or SAP. The latter doesn’t process data but transfers it from one location to another as quickly as possible. Each CPU may contain up to seven to ten specifically-built and constructed cores for increased throughput.

2. Multiple input/output (I/O) cards

Each mainframe may contain as many as 160 I/O cards because they are designed for redundancy. This means that if one card malfunctions, others will take up its tasks until it is replaced.

3. High storage capacity

These systems have tremendous storage capacity, allowing them to process massive volumes of data on demand. It can store a vast quantity of data and interpret it according to user specifications. After data processing, the system can provide accurate findings with zero data inaccuracies.

4. RAS-based performance

All applications on mainframes are designed with reliability, availability, and serviceability (RAS) in mind, which distinguishes the machine from other systems. With the aid of these computers, data processing is simple, and businesses use the scalability characteristic of the system to work with varying storage capacities. The CPUs within the system sustain the computational power of all of these apps.

5. No interruptions in the functioning

When updating software on a mainframe, workloads are distributed across the processors so that productivity is not hindered. In other cases, pausing the system might be prohibitively expensive for the business. If the organization is a financial institution, it could even endanger national security because of the inability to process applications. The primary function of mainframes is to make important systems accessible around the clock.

6. Multiple operating systems on the same machine

Multiple operating systems may be hosted on a particular mainframe. For instance, it is typical to utilize z/OS alongside Linux on a single mainframe. z/VM, z/VSE, Linux for System z, and z/TPF are the four dominant operating systems for mainframes, along with z/OS.

7. Throughput-driven fault-tolerant computing

A substantial quantity of output and input data is sent to the system. This means that mainframes must be able to manage all of this data, applications, and processes with ease. The quantity of data transported to or from a system does not affect mainframes. In addition, the mainframe ensures no errors occur while moving massive volumes of data inside its database. This feature is known as fault-tolerant computing.

8. Clustering technology

Mainframe systems support clustering technologies with close coupling (called Parallel Sysplex in an IBM environment). This capability enables the operation of up to 32 machines as a unified system configuration. Even if a system crashes, work will be completed seamlessly on the subsequent live system with no performance loss.

9. Centralization of computing processes

The mainframe system centralizes the administration of computing tasks. This implies that all activities occur in the mainframe’s processing section, and the results are shown on a client’s desktop monitor. The user may interact with an application or utility operating on the desktop while the mainframe operates in the background.

10. A move towards flexibility

Today, however, the difference between centralized and distributed computing is rapidly diminishing. Consequently, mainframes are routinely combined with clusters of simpler servers in a range of topologies. Modern mainframe hardware and software assets (like processors, storage, and device interfaces) may be reconfigured dynamically while programs continue to operate. This highlights the adaptable and evolving nature of modern mainframes.

11. Performance advantages over servers

The properties of mainframes must be comprehended in relation to servers and their intrinsic differences. Although the words are often used interchangeably, mainframes and servers are unique in the following ways:

  • Size: Physically, a standard commodity server is smaller in size than any mainframe. This is not due to the scale of mainframe computers. These days, mainframe computers are roughly the equivalent of a refrigerator. However, a server tray of the same size might accommodate around 12 low-cost servers. Mainframes will most certainly be bulkier than conventional servers due to the computing hardware resources it contains.
  • Throughput: If a standard server can process 300 transactions per second, this translates to around 26 million transactions each day. This is a substantial figure, but it pales compared to the trillions a mainframe can manage. IBM claims that Z13 mainframes can process 2.5 billion daily transactions.
  • Versatility: It is not possible to migrate mainframe workloads to commodity servers. However, you may shift tasks to a mainframe that would ordinarily be executed on a commodity server. What this means is that mainframes offer the best of both worlds. Users can access mission-critical applications that cannot operate elsewhere and manage server workloads on commodity hardware.

Top 6 Benefits of Mainframes

Nowadays, mainframe computers play an essential role in the everyday operations of most of the world’s top enterprises, including Fortune 1000 corporations. Despite developments in other forms of computing, mainframes remain significant in finance, banking, medical services, insurance, utility, administration, and many other private and public sectors. 

Benefits of Mainframes

1. Enable cloud-ready and scalable infrastructure

For cloud deployment, mainframes enable a range of highly secure virtualized environments. This comprises the z/VM operating system, blade servers, hypervisors, as well as logical partitions (LPARs). In addition to supporting millions of users with greater speed, mainframes are the best platform for big data analytics, data management, and web applications. Consequently, the technology is highly scalable.

2. Maintain compliance and security

Mainframes support industry standards, compliance regulations, and best practices with the help of data encryption, role segregation, privileged user monitoring, secure communication systems, audit reporting, and other mechanisms. It provides enterprise-wide visibility and a high degree of security transparency, enabling improved control. In addition, private clouds built on mainframes may reduce the inherent security risks of public cloud services with open networks.

3. Simplify the migration and consolidation of workloads

Transferring dispersed tasks to the mainframe setup is simple. This decreases the number of distributed systems that must be controlled. When your virtual environment has been optimized, it is simple to consolidate various tasks on the mainframe while maintaining the necessary separation between systems. This also minimizes the license expenses that dispersed systems would incur.

4. Reduce the total cost of ownership

The biggest benefit of mainframe computers is their unparalleled longevity. These computers have an average lifetime of over ten years. Until that point, mainframe computers are often problem-free. Once the average lifetime has been achieved, consumers can choose between replacing or upgrading the unit.

In addition, there is a threshold at which increasing server numbers becomes more expensive than operating the workload on a mainframe. Research on security managementOpens a new window determined that the total cost of ownership (TCO) over three years for a private cloud built on IBM zEnterprise systems was 76% lower than for a public cloud offered by a third-party service provider.

5. Ensure compatibility across generations

The operating system for mainframe computers supports a vast array of software and hardware. However, a mainframe will support most software, irrespective of the OS version. Even after an update, the system is still capable of running legacy programs. In addition, mainframe computers don’t limit the number of concurrent operating systems. Multiple operating systems can be created to function, thereby enhancing the system’s overall performance.

6. Compatible with blockchain technology

Blockchain is among the most fascinating new applications for which mainframes are an ideal match. In terms of reaction speed, transaction throughput, scalability, or security, the mainframe is the perfect blockchain host over x86 servers.

Additionally, its security advantage is a decisive advantage. The blockchain approach is predicated on transaction data carried in a network of immutable data blocks that cannot be altered once assembled. Mainframes can deliver 100% encryption without affecting performance due to their higher computing capability.

While mainframes remain essential for the reasons mentioned above, they also have a few drawbacks. Before setting up a mainframe computer system, one should examine the following:

  • Complex implementation: Due to its physical components, establishing a mainframe computer is more challenging than installing a typical computer.
  • High initial outlay: The initial outlay of a mainframe is substantially more than that of a standard server or the cloud.
  • Complex maintenance: The management of mainframe computers cannot be undertaken by ordinary IT personnel. It requires operations management and, in particular, system debugging.
  • Environmental conditions: Mainframes have additional environmental limitations like maintenance of temperature and humidity.

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Examples of Mainframes

While mainframe-like computing techniques are widely used, actual mainframe computers are not very commonly seen in circulation (apart from IBM models). Keeping this in mind, here are a few notable examples of mainframes:

1. IBM Z

IBM refers to all of its z/Architecture mainframe machines as IBM Z. In July 2017, with the introduction of a new generation of products, IBM z Systems was rebranded as IBM Z. The IBM Z line of mainframes presently comprises the latest model, IBM z16, along with z15, z14, and z13, as well as IBM zEnterprise, IBM System z10, IBM System z9, and IBM eServer zSeries models.

The IBM Z family preserves 100% backward compatibility. In practice, modern systems are the direct offspring of the System/360, which was introduced in 1964. Half a century later, the newest IBM Z system is compatible with most software created for older systems.

2. FUJITSU Server GS21

FUJITSU Server GS21 is ideal for mission-critical corporate and social infrastructure systems that must operate 24×7. Fujitsu has been continuously enhancing mainframe processing speed, functionality, and standards over the last 50 years to meet emerging demands.

The FUJITSU Server GS21 can manage massive amounts of data and ensure high availability at a reduced total cost of ownership. However, Fujitsu has declared that it would cease selling mainframes in 2030, with maintenance & support ending in 2035.

3. UNIVAC 9400

Several decades ago, the 9400 was created for mid-sized organizations seeking simple system expansion. In the 1960s, a UNIVAC 9400 mainframe was used in the computer center of a Cologne industrial complex. After being replaced by new technologies and hardware, the system was donated to a school in Cologne. From there, it was moved to the technikum29, a German computer museum, in 2005, where it remains functional to this day. 

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The biggest benefit of mainframes is their ability to run critical applications at a very large scale. Not every business might need a mainframe, but those that do, rely heavily on mainframe computers for business-critical processes. Particularly banks and large financial service providers need mainframes to support transactional processes without interruptions or downtime.  

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