Mainframe computerprocessing large applications and data. With a very expensive price and its function also to process data and applications that are very large, Mainframe Computers can only be used by large companies as well as Government and Banks. Mainframes can serve hundreds and even thousands of users simultaneously. Besides being expensive, this computer consumes a large amount of electricity. Mainframe uses in the banking sector are for transactions and in the field of government are usually used for censuses, vehicle taxes, military purposes, research research.
Advantages and Disadvantages of Mainframe Computers
- Having more than one processor.
- Can be used by many users (multi user).
- Can open several applications at the same time
- Using time sharring technology.
- The working speed of the processor is up to 1GOPS (Giga Operations Per Second).
- Because of its large size, a large space is needed to store it.
- The price is very expensive.
- The user interface still uses text.
- It works so long.
- Requires very electric power
- CPU, the CPU mainframe consists of several components, namely Processor, Memory, and Channel.
- Communication Device, which is a device / device used in a computer network system that functions to connect over long distances (for example: Hubs, Repeaters, Switches, Modems). On mainframe network systems, the device used is the Communication Controller.
- Disk Storage Device, is data storage in a mainframe computer system in the form of a disk. Storage capacity can reach thousands of GB.
- Tape is a media device for transferring data from disk to cartridge. Transfer rate can reach 40,000 KB / s. Connectivity
In general, connectivity to Mainframe Systems is as follows:
- Parallel Channel, has an average speed of up to 4.5MB / s, mileage reaches 122 M, type Byte Multiplexer (able to operate with relatively high data rates but with only one device at a time or able to operate in many devices but has relatively low speed), Block Multiplexer (designed for high speeds limited to complete interleaving data blocks.
- Escon Channel (Enterprise System Connection), has an average speed of 200 Mbps, Optical Fiber Pair, and reaches almost 3 Km.
- Ficon Channel (Fiber Connection), has an average speed of 20 Mbps, distance to 20 Km.
- OSA (Open System Adapter), is a network controller for mainframes and supports Ethernet, token ring, FDDI, ATM, GbE, FENET, 1000Base-T networks. For token rings have an average speed of 4-16MB / s and Ethernet 10MB / s, 100MB / s. For OSA Console Support using 1000Base-T.
- CTC (Channel to Channel), connects the CPU with other CPUs or LPAR with other LPAR via ESCON or FICON connections.
- Hypersocket, connecting one LPAR with another LPAR via CPU memory.
All these hardware components are separated from each other and connected to the CPU Mainframe itself. for example the network system in the following figure:
- CPU - Basic Vs LPAR Mode
- Basic Mode, One CPU only runs one OSLPAR Mode, One CPU is logically broken into several partitions (using the PR / SM - Processor Resource / System Manager) feature. Each partition runs one OS.
Operating System is a group of programs that manages the internal workings of a computer system. OS is designed so that various computer resources are used as well as possible, and guarantee a maximum work and processed efficiently.
The OS on the z Series mainframes consists of several, including:
• z / VM
z / Virtual Machine (z / VM) has two basic components: a control program (CP) and a one-user operating system (CMS / Conversational Monitor System). As a control program, z / VM is a hypervisor because it runs other operating systems in terms of creating virtual machines. Another major component is the Conversation Monitor / CMS System. The component of z / VM runs in a virtual machine and provides an interactive user interface.
• z / VSE
z / Virtual Storage Extended (z / VSE) is popular with small-scale mainframe users. z / VSE operating system provides less complexity for batch processing and transaction processing. z / VSE was originally known as the Disk Operating System (DOS), and was the first disk-based operating system (DOS) on mainframes that was introduced for S / 360 computers.
Z / OS
z / OS Operating System consists of a load module or executable code. During the install process, the system programmer copies the module load to load libraries on the volume. z / OS - Multiprogramming and multiprocessing. Multiprogramming - Ability to execute multiple programs at the same time. Multiprocessing - The ability to operate two or more processor shares of various hardware resources such as memory and external disks
• z / TPF
z / Transaction Processing Facility (z / TPF) The operating system has a special purpose system used by companies with high transaction volumes, such as credit card companies and flight reservation systems. z / TPF was once known as the Airline Control (ACP) Program. This is still used by airlines and has been used for other large systems that require high transaction speeds and volumes. TPF devices are formatted such that individual pieces of data can be accessed directly by disk.
Some (non-IBM) linux can be used on mainframes. There are two generic names for system distribution:
- Linux on S / 390 (uses 31-bit and 32-bit registers)
- Linux on z System (using 64-bit and registers)
The phrase Linux in System z is used to refer to Linux running on S / 390 or System z systems, when there is no specific need to explicitly refer to either 31-bit or 64-bit versions.
Linux characteristics on mainframes include:
Linux uses the traditional count key data (CKD / count key data) of a 10disk device and SAN-connecting SCSI. Mainframe systems can recognize this drive as a Linux drive, but cannot use the data format on the drive because it cannot be shared with other operating systems. Linux does not use the 3270 terminal screen, while all other mainframe operating systems use 3270 as the basis of the Linux Terminal architecture. they use terminal X Window System based or Window System X emulators on PCs, but also support ASCII terminals, usually connected via the telnet protocol. The X Window System is the standard for graphical interfaces on Linux. This is the middle layer between the hardware and the window manager.
With the right settings, the Linux z / VM system can be cloned separately to Linux quickly. LAN z / VM can be used to connect multiple Linux and to provide external LAN routes for them. Read-only file systems, such as system / user files can be shared by linux servers.
Linux on mainframes operates with ASCII character sets, not EBCDIC12 stored forms are data that is normally used on mainframes. Here, EBCDIC is only used when writing such as displays and printers. The Linux driver for this device handles character translation.
multiprogram batch system
Understanding Batch Systems, Multiprogramming, Time Sharing, Embedded Systems, Personal Computers, Understanding Handheld Devices
1. Batch System A batch system is where similar jobs are collected and run as a group then after the group that was run was finished then another group is automatically run.
Multi programming system is where jobs are stored in main memory at the same time and the CPU is used interchangeably. This requires some additional capabilities, namely: Provision of I / O routines by the system, memory settings to allocate memory to several jobs, CPU scheduling to choose which jobs to run, and other hardware allocations.
3. Time Sharing
Time-sharing is a method where many users can do processing in one computer.
4. Embedded system
Embedded systems are computer systems specifically designed for specific purposes in order to improve the function of a machine. As the meaning implies, "embedded" which means "matching", the matched part includes hardware and other mechanical parts. This is in contrast to the general system as we know it in Personal Computers (PCs) which can run many commands at the same time depending on the programming.
5. Personal Computer
Personal Computer or PC is the type of computer that is most widely used today. PCs designed for single users were actually introduced by IBM for the first time in 1981. If the previous generation, the shape of the computer was so large that it was impractical, so since the discovery of the chip in 1971, the size of the computer became smaller. Besides being more practical, the price of a PC is also much cheaper when compared to the previous computer.
6. Understanding Handheld Devic
A handheld device is a computer that is small enough to be grasped. This handheld computer can work with almost the same function as a normal computer. Although it is very easy to carry, a handheld computer cannot replace a normal computer (PC) because it only has a keyboard and a small screen. Some manufacturers try to solve the problem of keyboards that are too small examples of personal digital assistants (PDAs). The keyboard was replaced with an electronic pen. However, this electronic pen still relies on handwriting recognition technology which is still in the development stage.
The advantage of this handheld computer is that users can store and manage data more efficiently and accurately. Usually handheld computers are equipped with Bluetooth technology. Bluetooth is right for printing wirelessly, connecting a handheld computer with a mobile printer. Not only with printers but handheld computers can also be connected with other devices via Bluetooth connections.
Handheld computers can increase user productivity and make it easier for them to work more efficiently. The most widely used handheld computers are computers specifically designed to provide PIM (Personal Information Manager) functions, such as calendars, agendas, and address books.
Task of the operating system 3) Batch system, Multi programming system, Time sharing system, Multi processing system, Distributed system.
TERMS - TERMS OF OPERATION SYSTEM
MULTIPROGRAM BATCH SYSTEM
Some jobs are collected by the operating system in main memory at a time
the same, as in Figure 1-3. This job collection is part of the job
stored in the pool (job pool). Job pool contains jobs that are ready to be executed.
The number of jobs that can be stored together in memory is usually smaller than
the number of jobs that can be in the job pool. The operating system takes several jobs
which is ready to be executed to be put in main memory. If the job is being
executed waiting for some task (such as mounting a tape drive or I / O operation
which must be completed), then the job is replaced by the next job.
In a multiprogramming system, the operating system must provide a mechanism
for memory management, CPU scheduling and disk management. Operating system
multiprogram provides supplies for I / O routines. The system must be able
allocates memory for several jobs. Some jobs are ready to be executed
will be chosen by the job system which will be executed by the CPU. Any device
required by each job must also be allocated by the system.
Multiprogramming is a basic form of parallel processing that makes it possible to run multiple programs at the same time. A multiprogramming computer can be interpreted as a computer system that has been allocated with resources for more than one concurrent application, job or user. The multiprogramming capability was developed as a feature of an operating system in the late 1950s and began to be used on mainframe computers in the late 1960s. This follows the development of a hardware system that has a logic circuit and the instruction set needed to facilitate the transfer of control between the operating system and one or more other independent applications.
In multiprogramming, when a program is executed, another program is waiting. After the waiting program is finished, the CPU will return to execute it. As long as a program needs to be executed, the CPU is never idle. Switching processes between programs is called switching.
A concrete example of multiprogramming itself is: running a Microsoft Word program together with Windows Media Player.
Multiprocessing is an information technology term in English that refers to computer processing capabilities that are carried out simultaneously. This is possible by using two or more CPUs in a computer system. This term can also refer to the support of a system to support more than one processor and allocate tasks to these processors.
Multiprocessing also sometimes refers to the ability to execute several software processes in a system simultaneously, when compared to a process at a time, although the term multiprogramming is more appropriate for this concept. Multiprocessing is often implemented in hardware (using multiple CPUs at once), while multiprogramming is often used in software. A system may be able to have these two capabilities, one of which, or none at all.
Types of multiprocessing
Multiprocessing can be divided into several classes, namely:
Based on the symmetry, multiprocessing can be divided into
- Asymmetric Multiprocessing (ASMP)
- Symmetric Multiprocessing (SMP)
- Non-uniform memory access (NUMA) multiprocessing
Based on the number of instructions and the data, can be divided into (see Flynn's Taxonomy)
- SISD (Single Instruction on Single Data Stream)
- SIMD (Single Instruction on Multiple Data Streams)
- MISD (Multiple Instruction on Single Data Stream)
- MIMD (Multiple Instruction on Multiple Data Streams)
Based on the closeness between processors, it can be divided into
- Loosely coupled
- Thightly coupled
Multitasking is an information technology term in English that refers to a method in which a lot of work, also known as processes, is processed using the same CPU resources. In the case of a computer with a single processor, only one instruction can work at a time, meaning that the CPU is actively processing instructions for that one job. Multitasking solves this problem by scheduling which jobs can run at one time, and when other jobs waiting to be processed can be done. The condition of allocating the CPU from one job to another is called a context switch. When context switches occur very quickly - this condition is enough to give the illusion of parallel processing. Even in computers that have more than one CPU (called multi-processor), multitasking allows more work to be done than the number of CPUs available.
Computer operating systems can also adopt various scheduling strategies, which can be broadly categorized as follows:
In a multi-program system, work that is being processed continues to require an operation that requires outside interaction. (e.g. reading from tape). Multi-program systems are designed to maximize CPU usage.
In a time-sharing system, the work being processed is required to release CPU work, either voluntarily or from outside interactions, such as hardware-interruptions. The Time-sharing system is designed to allow multiple programs to be processed simultaneously.
In a real-time system, some waiting programs are guaranteed to get processing from the CPU when outside interactions occur. Real-time systems are designed to carry out mechanical controls such as industrial robots, which require processing accuracy.
Today, the use of the term time-sharing is rarely used, and replaced with the term multitasking.
Time-sharing is sharing of computing resources between many users through multiprogramming and multi-tasking. The concept of time-sharing is a way in which a system allows multiple users or processes to use CPU and memory. In this system, the operating system will rotate the processes that are running, and allow each process to be run by the CPU (and stored in memory), before moving to the next process. These machines have become fast enough so that most users can feel as if they are using the machine only for themselves. In theory, time-sharing can reduce computing costs significantly, given that a machine can be used by several users, some even reaching hundreds of users
3 Distributed Processing / Computing
Management of many processes that can be run by a number of computers that are distributed (distributed). Operating systems that carry out distribution tasks such as AMOEBA, MATCH, LINUX.
The current computer system trend is distributing computing between
some processors. The processor communicates with other processors through the channel
communication, for example high speed buses or telephone lines. This system is called
loosely coupled system or distributed system (distributed system).
Processors in distributed systems vary in size and function. Usually
consists of microprocessors, workstations, minicomputers and generalpurpose computer systems.
These processors are called site, node, computer or others.
The advantages of a distributed system are:
• Resource sharing
If a number of different sites are linked, then users on site one can
use resources from other sites. For example, users on site A can
using a laser printer from site B. Instead user B can access user file A.
• Increase computing speed
If certain computations can be partitioned in a number of sub computations that can
run concurrently, then the distributed system can distribute
computing at several sites to run concurrent computing.
• More reliable
If one site fails on a distributed system, the rest of the site can resume operations.
If the system is divided by a large number of installations, then the failure of one is not
the rest of the system. Conversely, if the system is divided into a number of machines
small, each responsible for important system functions