Who uses mainframe computers?

So, who uses mainframes? Just about everyone has used a mainframe computer at one point or another. If you ever used an automated teller machine (ATM) to interact with your bank ccount, you used a mainframe.

Today, mainframe computers play a central role in the daily operations of most of the world’s largest corporations. While other forms of computing are used extensively in business in various capacities, the mainframe occupies a coveted place in today’s e-business environment. In banking, finance, health care, insurance, utilities, government, and a multitude of other public and private enterprises, the mainframe computer continues to be the foundation of modern business.

Until the mid-1990s, mainframes provided the only acceptable means of handling the data processing requirements of a large business. These requirements were then (and are often now) based on large and complex batch jobs, such as payroll and general ledger processing.

The mainframe owes much of its popularity and longevity to its inherent reliability
and stability, a result of careful and steady technological advances that have been made since the introduction of the System/360 in 1964. No other computer architecture can claim as much continuous, evolutionary improvement, while maintaining compatibility with previous releases.

Because of these design strengths, the mainframe is often used by IT organizations to host the most important, mission-critical applications. These applications typically include customer order processing, financial transactions, production and inventory control, payroll, as well as many other types of work.

One common impression of a mainframe’s user interface is the 80x24-character “green screen” terminal, named for the old cathode ray tube (CRT) monitors from years ago that glowed green. In reality, mainframe interfaces today look much the same as those for personal computers or UNIX systems. When a business application is accessed through a Web browser, there is often a mainframe computer performing crucial functions “behind the scene.”

Many of today’s busiest Web sites store their production databases on a mainframe host. New mainframe hardware and software products are ideal for Web transactions because they are designed to allow huge numbers of users and applications to rapidly and simultaneously access the same data without interfering with each other. This security, scalability, and reliability is critical to the efficient and secure operation of contemporary information processing.

Corporations use mainframes for applications that depend on scalability and reliability. For example, a banking institution could use a mainframe to host the database of its customer accounts, for which transactions can be submitted from any of thousands of ATM locations worldwide.

Businesses today rely on the mainframe to:
- Perform large-scale transaction processing (thousands of transactions per second)
- Support thousands of users and application programs concurrently accessing numerous resources
- Manage terabytes of information in databases
- Handle large-bandwidth communication

The roads of the information superhighway often lead to a mainframe.

(Dari Introduction to the New Mainframe: z/OS Basics)

Operating System Mainframe

Operating system (OS) apa sajakan yang dapat jalan di mainframe? Window? Tidak. Window sampai saat ini tidak bisa digunakan sebagai operating system mainframe. Berikut OS yang dapat jalan (/menjalankan=mengoperasikan) mainframe (anda pernah membaca atau mendengar OS OS ini?) :

1. z/OS – Saya sangat berpengalaman pada OS ini. z/OS yang ada sekarang adalah z/OS 1.10. (dibacanya: z/OS versi 1 release 10). Gambar diatas yang memperlihatkan evolusi OS ini. Saya mengalami OS mainframe sejak MVS/XA. Diikuti MVS/ESA 4.3, OS/390 1.2 –s/d- 2.10 sebelum berganti nama menjadi z/OS. Banyak pengguna mainframe di Indonesia menggunakan OS ini.

Operating System ini memungkinkan banyak subsystem run (=beroperasi) diatasnya. Transaction Server (CICS), Data base Server (DB2), IMS Web Server dll. Juga penggunaan bermacam bahasa pemrograman. Yang digunakan oleh user di Indonesia : COBOL, PL/I dan C. Saya sendiri mulai merintis untuk mempopulerkan JAVA di mainframe untuk Transaction Server (CICS) dan DB2.


2. z/VSE – z/Virtual Storage Extended. Operating System ini lebih sederhana daripada z/OS. Beberapa user mainframe di Indonesia menggunakan OS ini. Saya kurang berpengalaman di OS ini, pengalaman saya di OS ini hanya terbatas pada setup networknya.

3. z/VM – z/Virtual Machine. Operating System ini lebih sederhana lagi dari z/VSE. Biasannya user yang menggunakan z/VSE juga menggunakan OS ini. z/VM dipakai sebagai base operating system yang juga berfungsi untuk membagi bagi bagi satu box mainframe (physical) menjadi beberapa bagian (logical). Jadi dengan menggunakan z/VM kita bisa membagi satu maiframe (physical) menjadi beberapa partisi (logical). Sesuai namanya VM = Virtual Machine.
Didunia mainframe konsep virtual machine (=Logical Partition, LPAR) bukan barang baru. Sudah ada sejak lama.
Diatas z/VM ini bisa run berbagai jenis OS mainframe. Bahkan z/OS!
Saya punya pengalaman yang bisa dikatakan lumayan di OS ini.

4. z/Linux – Redhat dan SuSe
OS ini dapat run di mainframe. Baik langsung sebagai base operating system ataupun run diatas z/VM. Satu user mainframe di Indonesia sudah menggunakan ini, saya ikut serta dalam implementasinya. Jadi saya punya pengalaman juga dibidang ini. Diatas z/linux ini bisa dijalankan berbagai aplikasi linux yang jalan di server server.
Dengan kemampuan run linux ini diiklankan bahwa mainframe dapat menggantikan puluhan server linux menjadi satu box mainframe saja. Jadi kalau anda ingin mengkonsolidasikan beberapa server linux base (> 10) anda, opsi ini bisa jadi pertimbangan. Tapi jika anda hanya punya 1 atau 2 server linux, lupakan saja opsi ini. Atau kalau anda punya mainframe, anda bisa membuat satu lpar untuk run linux.

5. z/TPF – TPF Ini bukan kependekan dari Tim Pencari Fakta seperti yang sedang populer. Tapi kependekan dari Transaction Process Facility. Operating System ini mempunyai kegunaan khusus, biasanya digunakan oleh user user yang menjalankan jumlah transaksi yang sangat besar, seperti kartu kredit dan reservasi penerbangan. Garuda menggunakan TPF. Pengetahuan saya dibidang ini sebatas teori, tapi saya pernah menjadi tecnical support untuk menangani system network TPF (SNA Network) di Garuda. Dan saya pernah ikut mengembangkan penggunaan socket koneksi TPF. Jadi saya juga memiliki pengalaman lapangan walaupun tidak sedalam z/OS.

What is a Mainframe?

Today, computer manufacturers don’t always use the term mainframe to refer to mainframe computers. Instead, most have taken to calling any commercial-use computer—large or small—a server, with the mainframe simply being the largest type of server in use today. IBM, for example, refers to its latest mainframe as the IBM System z9™ server. We use the term mainframe in this text (blog) to mean computers that can support thousands of applications and input/output devices to simultaneously serve thousands of users.

Servers are proliferating. A business might have a large server collection that includes transaction servers, database servers, e-mail servers and Web servers.
Very large collections of servers are sometimes called server farms (in fact, some data centers cover areas measured in acres). The hardware required to perform a server function can range from little more than a cluster of rack-mounted personal computers to the most powerful mainframes manufactured today.

A mainframe is the central data repository, or hub, in a corporation’s data processing center, linked to users through less powerful devices such as workstations or terminals. The presence of a mainframe often implies a centralized form of computing, as opposed to a distributed form of computing.

Centralizing the data in a single mainframe repository saves customers from having to manage updates to more than one copy of their business data, which increases the likelihood that the data is current.

Starting around 1990, mainframe processors and most of their I/O devices became physically smaller, while their functionality and capacity continued to grow. Mainframe
systems today are much smaller than earlier systems—about the size of a large refrigerator.

In some cases, it is now possible to run a mainframe operating system on a PC that emulates a mainframe. Such emulators are useful for developing and testing business applications before moving them to a mainframe production system.

Clearly, the term mainframe has expanded beyond merely describing the physical characteristics of a system. Instead, the word typically applies to some combination of the following attributes:
- Compatibility with mainframe operating systems, applications, and data.
- Centralized control of resources.
- Hardware and operating systems that can share access to disk drives with other systems, with automatic locking and protection against destructive simultaneous use of disk data.
- A style of operation, often involving dedicated operations staff who use detailed operations procedure books and highly organized procedures for backups, recovery, training, and disaster recovery at an alternative location.
- Hardware and operating systems that routinely work with hundreds or thousands of simultaneous I/O operations.
- Clustering technologies that allow the customer to operate multiple copies of the operating system as a single system. This configuration, known as Parallel Sysplex, is analogous in concept to a UNIX cluster, but allows systems to be added or removed as needed, while applications continue to run. This flexibility allows mainframe customers to introduce new applications, or discontinue the use of existing applications, in response to changes in business activity.
- Additional data and resource sharing capabilities. In a Parallel Sysplex, for example, it is possible for users across multiple systems to access the same databases concurrently, with database access controlled at the record level.

As the performance and cost of such hardware resources as central processing unit (CPU) power and external storage media improve, and the number and types of devices that can be attached to the CPU) increase, the operating system software can more fully take advantage of the improved hardware. Also, continuing improvements in software functionality help drive the development of each new generation of hardware systems.

(Dari Introduction to the New Mainframe: z/OS Basics)