1. Learn to manage information Technology
An urgent job in managing the Technology at the time of this architecture is the organization for processing information. In this chapter we will discuss the types of computers available at the time of this evaluation and presents the history of the computer. you are working in an organization that has been using the computer for a long time; company hardware architecture (hardware) may include multiple computers that are older. Set the computer to supply all the types of engines that vary in how they use the Technology and trends are constantly pushing the evolution of the organization's hardware strategy.
2. Preparation to take part in the system analysis and design
Although sometimes we get a design pressure of the system logic is not tied to the computer where the computer will be used, in some cases the designer must face Technology computer. A system design of large, multi-computer use will have characteristics of a character from PC users. End of this chapter also provides an overview of some tools that output or input is available. Activities help to give this definition that connects users with the system, which is important for the success of it.
3. Changing the organization
Had spent many years to make computers and communications that can change the company and industry. Companies that change itself has to know how to set up a series of differences from the computer and other equipment; their success in responding to the trend of the Technology and sustainable change in the cost comparison / display of the difference types of computers.
IMPLICATIONS FOR MANAGEMENT
What the implications of this for the management of Technology?
- Compare the cost / display on the computer continue to decrease; the price continuously falling as a result of the progress level of the computer. Logic function is no longer part of these machines. In the first generation, the CPU is the source of a rare and expensive. Currently, very large scale integration (VLSI = very large scale integration) using a common Technology can saving several million transistor chip in to a small Silicon. The process logic is now available with a relatively cheap price.
- Organizations spend a lot of money on the computer because a computer that can not be avoided for the fat applications. Given the amount of the cost may go down, total spending increased to Technology information in most organizations.
- Simple approach and use of personal computers to help provide more individuals to enter the computer Technology. To be able to compete in the coming years, a manager someone who must be proficient using the computer. It is very difficult to determine an architecture of the hardware and software that is suitable for companies with a lot of demand and availability of tools to compete. Rapid decline in the price of the chip (chip) that is very powerful means of making that the center has a cost / display characteristics better than the minis and Mainframe.
WHEN THIS COMPUTER
Can we achieve this property the computer now? In the time before, there is no diversity of species, all considered the same (the pad will be discussed later this chapter). At a time, 8 different companies in the United States manufactured computers. UNIVAC was the first lead in a computer but will then defeated IBM. (later to become part of the UNVAC Sperry, which merged with other computer vendors Burroughs, namely, to establish the company UNISYS).
IBM became the dominant seller in the United States and abroad, the computer industry sometimes described as "IBM and the seven cub" in the years 1950s and early 1960s, there is no company like Apple, Digital Equipment Corporation (DEC), and Compaq. RCA and General Electric to create the same computer, eventually taking a large deletion leaving their mini-computer business and the seller's primary defeat changes dramatically.
Computer Wizard
Not every application requires strength processing personal computer, in addition, tools such as small computers became more powerful Wizard every day. Brooklyn Union Gas has about 100 Wizard that is used for tasks that vary.
In one application of the user to represent the use Wizard to guide users through some of the regulations when they are asked to set up a report. An analysis of re-writing an application that is used in BASIC on a PC that can run the Wizard.
In Merck & Co. Some executives use the Wizard as a personal organizer, to report expenditures, and plan meetings. Company working on an application that will help managers, pharmacy manager in America Latin to run their sales territories. Now, IBM PC Wizard is a powerful speaker who appears in the year 1981, in comparison of the cost / view from the "commodity" chip processor system based on the proprietary circuit designs.
Technology trends in what the industry has created a computer at this time? Why so many different types of computers, and for what each type of computer designed?
In one application of the user to represent the use Wizard to guide users through some of the regulations when they are asked to set up a report. An analysis of re-writing an application that is used in BASIC on a PC that can run the Wizard.
In Merck & Co. Some executives use the Wizard as a personal organizer, to report expenditures, and plan meetings. Company working on an application that will help managers, pharmacy manager in America Latin to run their sales territories. Now, IBM PC Wizard is a powerful speaker who appears in the year 1981, in comparison of the cost / view from the "commodity" chip processor system based on the proprietary circuit designs.
Technology trends in what the industry has created a computer at this time? Why so many different types of computers, and for what each type of computer designed?
Development of Mainframe
Figure 8-1 shows the environment of a computer circulating. Computers on the Mainframe is developed a larger engine that is aimed at general. At the beginning of the computer industry, only one group that can run on the Mainframe computer. Many organizations have developed many applications on Mainframe computers; when this type of machine such as that used to support some terminal and interacting personal computer with a large database that holds billions of characters of data. Mainframe computers are used by many users with a process for the transaction and maintain access to important data. (more we discuss the future of Interior Mainframe). Based on history, IBM has dominated the market Mainframe, but the usual request for Mainframe has decreased, leading to a major problem for the company.
Power Super Computer
Mainframe computers are not fast enough for some applications. Mainframe computer developed for the original business; Mainframe computers have a surplus to increase the data processing business that involves the manipulation of characters and decimal arithmetic. Scientists and engineers have the problem count must be solved is intensive, often involving a number with more significant digits. Companies such as Cray offers a super computer for some work such as forecasting, data analysis geological, and some types of learning from the simulation. Super Computer including the fastest computer at this time, with the size of the speed in the 100 mega-flop (mega-flop is the implementation of the one million-instruction movement points per second) faster than giga-flop (one billion Instruction movement-points-per-second). Some companies try to achieve the tera-flop machine to machine that is capable execute one trillion instructions per second!
Minis: the beginning of the revolution began
Other types of computers are mini; companies such as DEC found that the combination of circuits they can make regular small computer which is very cost effective with the 8 or 16 bit long word. Minis became very popular as a stand-alone computer and is presented as the engine for the company.
Mini Computer has developed as a factory that has increased processing speed and font size to remove the 32 bit. Computers can be grouped as a "midrange". IBM has stated more than 200,000 sold from this system midrange AS/400. Some organizations have put into the network Mini Computer Mainframe. (for companies with a large number of applications with Mainframe Working, replace the computer with all Minis is not something that provides practical involvement of investment software that unusual).
Mini Computer has developed as a factory that has increased processing speed and font size to remove the 32 bit. Computers can be grouped as a "midrange". IBM has stated more than 200,000 sold from this system midrange AS/400. Some organizations have put into the network Mini Computer Mainframe. (for companies with a large number of applications with Mainframe Working, replace the computer with all Minis is not something that provides practical involvement of investment software that unusual).
Figure 8-1 KINDS COMPUTER MODEL
Personal digital assistant (PDA / personal digital Assistant)
Tool to help individuals with a record store, recording, and communication with others. Price: $ 500 to $ 2000
Personal computer (personal computer)
General purpose desktop computers that use 32 bit microprocessor. Price: $ 500 to $ 4000
Server. Server disk capacity is used to manage the large network personal computers. Price: $ 3000 to $ 15,000
Workstation
Computer display high 32 bits used by the engineers, scientists and technical experts who need professional workstation graphics superior. Usually used to design the computer, the display offers a mini-computer, but only one person to serve a station saved on the table or desk and connect workstation the other in a network. Price: $ 5000 to $ 100,000
Midrange (mini computer)
Categories this machine can handle the public needs more than 100 people, who generally work on the cable terminal on the computer. Mini size of the computer is approximately equal to 2 or 4 in the image file cabinet, often linked to some of the network to improve the company, such as a network that replaces the Mainframe. Price: $ 50,000 to $ 1 million
Mainframe Computers
Broad, general computer which aims to serve hundreds or thousands of users, all bound on a subset of the data center processing. Mainframe is generally more sparse and smaller than the Volkswagen Beetle and the room that requires regulated atmosphere. Mainframe generally handle the needs of the main processing large companies. Although many violations by the network mini-computer and PC, Mainframe leave on the main results of a large central processing. Price: not more than $ 5 million
Super Computer
World fastest computer, is used in science, science, engineering, and research to challenge processing the most difficult, such as weather forecast, the average super computer is not greater than the Mainframe package but a faster processor more closely linked to the speed of calculation . Some companies or organizations often share time on a super computer to generate the high price of this machine. Price: $ 1 million as $ 30 million
Parallel High Computer
Types of computers that use the relatively new 16 to 64,000 processors (for comparison, have a super computer 1 to 8 fast processors). Processors and shared their own work on the hunk of the big problems. Excel computer program in parallel with the many free operation can be completed at the same time they adjust the speed of super computers at a fraction of the cost / price, because the super computer can not be separated as soon as on where they can get data from memory, parallel machines that store memory on each micro processor to a better alternative. Price: less than $ 100,000 to $ 5 million
Personal computers have changed everything
Coming next is a PC or personal computer, which was first designed as an 8-bit computer, Apple introduced the PC in 1977. The original IBM PC, marketed in 1981, taking 8 bits in the same time from the memory 16 but showing a bit of time on the same calculation. IBM introduced the AT immediately, and take that process 16 bits at the same time, the next generation PC is 32 bits at the same time, or 386 (and 486 as well) that take and process 32 bits at the same time. Latest chip, pentium chip that is able to retrieve and process 64 bits at the same time.
Server is a PC that a high strength that is used to set up a network of PCs and other equipment. Serve in general have a wide range of disk capacity to store programs and data downloaded to a PC on the network when they request services.
Figure 8-1 shows the personal computer and workstation as a separate category. Workstation using a computer display 32-bit high for science engineering and scientific work. Workstation is equipped with superior graphics, and is often used to design tasks. Strength and 486 pentium PC running the user's graphics tool (graphical user interface = GUI) as well as workstations. PC has the ability and strength calculation software trap to be the same type of personal productivity tools for the manager while the workstation is the technical knowledge to engineer.
Parallel computer is a large-scale
Category parallel machines in Figure 8-1 includes several new computer design approach. new approaches have a common idea to try to avoid the draft bootleneak old where all the commands and data must be retrieved from memory and brought to the CPU to be processed. Some of the computer has parallel various processors that run the same command on the same data at the same time. Implementation of the various commands on different data. Clear that the implementation of the command to set the machine and the programming is a challenge.
One of the parallel computer with 65,000 1-bit processors have been used by information providers to get the system back on-line news. It is expected that the number of processors will result in a search of the files very quickly. IBM have created a super parallel computer based on RISC Technology RS6000 workstation with the type of the most successful; SPI is related as much as 64 chip and can run almost all software that is currently running in this workstation. Some experts expect the computer replaces the Mainframe parallel computer when the physical limits of the calculation achieved, one way to improve is to look execute count in parallel.
Strategy recently followed by a few users who need a count with a very high speed with the current group of workstation with special software that another attack the same problem. Software to set some parts of the complex calculation for several workstations, increased generation of a reasonable consideration in the processing power. It is possible that some applications require Super Computer used to run on several groups of workstations that are interconnected.
Personal Accessory
Computer is the new personal digital adjuvant (PDA = personal digital assistant). This machine started as a super calculator that is able to save the calendar and phone book. When this tool, such as Apple Newton, often have less weight than one pound, offers some of the handwriting and voice, fax and modem communications, and even a everywhere (pager). PDA is an application that is cheap enough that the company will develop for them. For example: sales reports can use the PDA with a small contract information. Workers will use the PDA with a bar-code reader and scanner to record the location of the container. PDA will also become a consumer product. For example, a car rental companies have a local supply of maps and tour guides in each city for download to your PDA.
We can see why the work of architecture to a company calculation system is very difficult. If an organization does not start with the calculation, the estimate will be to buy a lot of mini-computers, a small Mainframe, personal computer or network. Choice questions which must be selected and primary education requires significant effort. Organizations that already have a number of the computer to decide how to organize and expand this system to address the needs of users and new ideas calculation.
Chip
All this while using a computer chip circuit integration, small size (5mm to 10 mm on a side) that are generally made on a Silicon transistor load millions. There is logic to the CPU chip and memory chip for storing data; chip memory are often shown with DRAMS (dynamic random-access memory chips = chip dynamic random access memory). Chip is responsible for the power of modern computers; now millions of components made in the chip. The previous chapter, the DEC alpha chip; DEC has a claim to speed the processing of the 400 million per second for at least one version of the chip, faster than most Mainframe and even some super computer. Intel 486 processor chip, has a 1.2 million transistor Pentium whereas as the next generation after the 486 has more than 5 million transistor. Million cost of computers, thousands of dollars from purchasing price per order of a million per second, the computer may have been conducted continuously decreased. Figure 8-2 shows how many MIPS (million instructions per second of speed = speed of execution services commands millions per second) that was purchased with the price of $ 100 in successive generation of Intel's chip to start introducing the Pentium chip. The decline in prices to increase dramatically the amount of force the computer has made possible the trend discussed in this text. Currently, desktop computer display Mainframe computers five years ago in terms of strength calculation. Technology to encourage organizations to deliver applications to end users. Solution that is used to implement Mainframe now can not be easily treated with a desktop machine.
As a result, we expect to see more computer network; Mainframe, minis and PCs interconnected will that the various processing tasks. Decide what type of computer is suitable for an application and where the machine will continue to be allocated to the development of architecture for a new system.
What makes the chip work?
- What factors are responsible for the extraordinary appearance of the PC processor? Table 8-1 contains data in the form of a special design of the Intel chip strength of popular IBM PC compatible with it. Figure 8-3 presents a graph and a speed chip transistor on successive generation of chip. Views from the processor chip in the PC form the rows of the table 8-1:
- Speed minutes. It set the clock speed of engine cycles. If other enduring constant, increasing the speed of the chip will hours increase.
- Data flow. Data flow or the size of the bus indicates how much data is transferred between memory and CPU with each command. If the other constant, has a large data flow engine speed because the shorter trip to the memory needed to process the data.
- Counts. If the chip can count on a bit more at the same time, the conduct of commands more quickly because the command will be executed with a shorter time.
- Memory Size. More memory will make the program most often perform more quickly. This is especially important when using the graph where you have more than one program is filled at the same time.
- Threshold-point arithmetic. If the chip has been made in the threshold-point arithmetic (or use co-processor with threshold-point arithmetic) calculation of the numbers will be faster because they will be displayed in the hardware rather than software.
- MIPS (million per second = instruction command millions per second). This figure is an indication of line speed on the chip.
- The number of transistor per chip. The densely packed transistor in general the more quickly its chip.
The first IBM PC is a very slow machine to the standard at this time! (not one to predict the dramatic success of the personal computer, not even our predictions a large increase in processing power and decrease in price). Chip 286 or AT (for a more advanced Technology) has a significant impact on the display. Hours and increased speed of data flow between memory and CPU folded double in size. Current generation chip, n86, is very forceful with the possible speed of more than 12 hours times the speed of the PC original and more than 30 times the memory. This machine (except for 386x) makes data show the count and 32 bits each time. Members of this family is that the Pentium with more than 100 MIPS.
Tricks that can increase the speed?
Although this special session will help you choose the computer, this discussion is not enough, because factories had to bring a number of tricks to make your PC so much faster. The first option is a secret reserve memory (memory cache), namely high-speed memory that is used to increase the speed of the slower memory. Consider a disk drive where the disk drive can take an average of 12 millisecond to access the data. Instead of direct transfer of data into the memory center, the place in the memory secret reserve (cache memory) which is made of semiconductor. Secret reserve memory (cache memory) can have 32k or more storage capacity. When the computer to read from disk, memory savings secret (memory cache) filled with the data request and the extra data at hand. (data access often occur close together), if the reader next to the material in the secret place of deposit (cache), it can be moved to main memory on the memory speed from the speed of disk access. Of course if there is no "collision" in the secret place of deposit (cache) means that the requested data is not there and the computer must get data from the disk.
A secret reserve (the cache) can be used almost in every place to increase the speed of the computer. Many PC using a cache with main memory; 8-megabyte memory can be used with 128 kilobytes cache. You can also use a separate cache or memory controller with the video speed to add a video.
Intel also has developed a series of chip equipped with the multiplication hour (clock doubling). Hours on the CPU speed is two times the speed of processing at the beginning of the chip. For example, someone can buy a clock-doubled 66 megahertz 486 chip in a PC. All operations on the chip held on 66 megahertz; the beginning of the operation of the chip (eg, access memory) occurred in 33 megahertz. Reduplication day become famous as the processor can use the chip to the memory working in more than 33 megahertz. (there are some problems reported when the memory chip factory to try to run the day to speed very quickly, its chip tend to overheat and melted).
Equipped with a Pentium chip integer execution units (integer execution unit) each provide inputs from the command line itself. This architecture means that the pentium can implement the two hours of unity. Programs that translate the high level language into machine language (discussed in the next chapter) should be modified to find out the program that the user can operate parallel to separate; not be able to implement the chip flow of the two at the same time, some operations will be conducted with sequentially.
Since many PC applications are now equipped with graphic features, the factory has a computer switch their attention to the video and this is in the computer. Fastest machine that has features of a local video bus (local bus): flow controller from the CPU to run at video speed bus that closer distance between the memory and CPU from the bus that is used for something less important, such as a printer or modem. The graphics card speed controller is a video that actually has a chip on the computer processor and large amount of memory (just say, a megabyte) to offload the work from the CPU display.
Finally you can buy a computer with a wider bus and faster CPU that connect to the things less important. Initially, all the components your PC using the same bus-video, memory, printers and more. As discussed earlier, 32-bit CPU has a 32 bit data flows themselves (in general) to the memory. Some machines are also equipped with video to speed up the operation again. You can also buy a bus for connecting other components, such as disk or printer, which provides more than standard data bus at this time 16 bit ISA (industry standard architecture), the same bus from the PC AT. IBM offers a micro-channel architecture that can move 32 bits at a time together. Factory groups together the other computer ( "gank seven") to develop their own version of the 32 bit bus which they call EISA (extended industry standard architectur) compared to the IBM.
All these factors can cause a dramatic impact on a PC display. Not always the case that each computer with the speed of the fastest hour faster than the speed of the computer that day and then more slowly if the engine has a number of features to improve the strength.
Intel also has developed a series of chip equipped with the multiplication hour (clock doubling). Hours on the CPU speed is two times the speed of processing at the beginning of the chip. For example, someone can buy a clock-doubled 66 megahertz 486 chip in a PC. All operations on the chip held on 66 megahertz; the beginning of the operation of the chip (eg, access memory) occurred in 33 megahertz. Reduplication day become famous as the processor can use the chip to the memory working in more than 33 megahertz. (there are some problems reported when the memory chip factory to try to run the day to speed very quickly, its chip tend to overheat and melted).
Equipped with a Pentium chip integer execution units (integer execution unit) each provide inputs from the command line itself. This architecture means that the pentium can implement the two hours of unity. Programs that translate the high level language into machine language (discussed in the next chapter) should be modified to find out the program that the user can operate parallel to separate; not be able to implement the chip flow of the two at the same time, some operations will be conducted with sequentially.
Since many PC applications are now equipped with graphic features, the factory has a computer switch their attention to the video and this is in the computer. Fastest machine that has features of a local video bus (local bus): flow controller from the CPU to run at video speed bus that closer distance between the memory and CPU from the bus that is used for something less important, such as a printer or modem. The graphics card speed controller is a video that actually has a chip on the computer processor and large amount of memory (just say, a megabyte) to offload the work from the CPU display.
Finally you can buy a computer with a wider bus and faster CPU that connect to the things less important. Initially, all the components your PC using the same bus-video, memory, printers and more. As discussed earlier, 32-bit CPU has a 32 bit data flows themselves (in general) to the memory. Some machines are also equipped with video to speed up the operation again. You can also buy a bus for connecting other components, such as disk or printer, which provides more than standard data bus at this time 16 bit ISA (industry standard architecture), the same bus from the PC AT. IBM offers a micro-channel architecture that can move 32 bits at a time together. Factory groups together the other computer ( "gank seven") to develop their own version of the 32 bit bus which they call EISA (extended industry standard architectur) compared to the IBM.
All these factors can cause a dramatic impact on a PC display. Not always the case that each computer with the speed of the fastest hour faster than the speed of the computer that day and then more slowly if the engine has a number of features to improve the strength.
Computer generation
Technology has improved to obtain a trend that important, would help to see the difference in the computer generation that has passed. Because only the first 20 years produced Mainframe computers, Mainframe we discuss in the previous chapter that introduces the difference between PC and Mainframe modern computer.
Figure 8-4 shows the general model of Mainframe computers. One important difference between computer Mainframe and personal computer is not the bus architecture. Mainframe equipped with the most direct connection between the CPU and memory, the data does not pass, and proceeded to skip the bus. Bus architecture with modules more easily seen from the tools for connection to a different bus. In the previous bus architecture Mainframe more slowly and require direct connection to the speed.
Mainframe computer specialty starts with a processor. Mainframe is now common use of a series of commands (a series of commands that are generally dedicated and regulated by the seller) and the software that has a variety of processors. Various tiger-processor for the right owner of architecture vendors like IBM is relatively small, the order for 2 or 4 per computer.
In order to maintain the role of the Mainframe and to give strength processing that some applications need, computer companies are in the process of re-found Mainframe. The idea is to create a Mainframe-class machine that is issued from a number of chip cheap. For example, Mainframe-class computer from Hewlett-Packard (HP) and a group of DEC features of microprocessor quickly as opponents of the draft common Mainframe IBM 370 processor architecture. HP and DEC machines sell about $ 10,000 million instructions per speed per second (MIPS) compared with the IBM Mainframe to $ 30,000 to $ 80,000 per MIPS.
Mainframe computer organization using a common process large amounts of data. Computers may be able to access a database with billions of character data and manage hundreds or thousands of network terminals. As a result, the computer needed to be able to handle many activities and operations of communication input / output.
Mainframe channel usually has the data, which has the same power with the CPU on a computer that is smaller. Channels receive the data from the CPU, for example, take back the data from the disk file. While the data channel is busy the CPU to continue other work. channel when the data is complete, then interrupt the CPU that data is available. CPU and me to restart the program has been on the sidelines that this program is more important and higher than in the other program is waiting to run.
Only with the personal computer, the unit served on Mainframe computers to connect, in this case the data channel with the tools and save the I / O is different. This architecture has created Mainframe computers are very fast, which is used in the database, processing command, and other applications that count.
Brief history
Computer experts often expressed about the generation of a different computer, the general faithful generations together to introduce new computer hardware dean Technology clearly different with the earlier. Generation of succession has also been on the mark with a dramatic change in appearance. Each new generation has proven the increase of fast calculation speed and save more with a price lower than the equipment used. Generation computer can also be a characteristic change in the software; in chapter 8 we discuss the characteristics of the software in each generation.
Computer generation in the first component with a characteristic vacuum-tube (vacuum cleaner tubes) and rotation memory. One of the most popular models such as the IBM 650.
Second-generation computers use components for the center transistor processing unit and for the magnetic core memory. Channel data appear in this generation, in line with specific features to increase the CPU speed. Computer system used in the first commercial on-line communication and involving the division of time for the system, where users are given the ability to count through the terminal.
Third-generation hardware in the computer with the more characteristics of a large number of circuits and monolithic mini direction (the number of electronic components on the chip) to the center processing unit. Many features of the CPU is added to improve the work in this generation. Three-generation engine to make it easier to improve on-line applications that require telecommunications capabilities.
Developing the third generation to generation in the three and a half through the use of Technology for semiconductor memory in some of the main engine. The concept developed from the time the so-called "virtual memory" was also implemented through a special hardware facilities. (see part of the virtual memory on the next chapter)
Generation of computers to the four characteristics by the very large, a fast semiconductor memory, small size, and the needs of smaller energy. Fourth-generation engine is designed to facilitate the development of applications on-line facilities and the use of a large database.
Warehouse secondary
Generally refers to the secondary storage devices that store must be accessed through the data channel or bus; CPU can not carry data or commands directly from the equipment saving. There are several reasons why the use of secondary storage. First, we are often not able to have enough main memory to process data in large numbers. Some applications have a file which contains billions of character data, and can be a burden beyond the capacity of main memory is available at this time.
Although we have enough main memory and the physical can burden with on our computer, we will not want to fill it with data! Many programs use the main memory, each processing the data. If we always save all the data for one application in memory, then we have to give computer all or part of a special computer just for that application. Therefore, we do not want to store data that is not needed in main memory. Secondary storage devices provide a flexible capability storage for data and programs.
In general, the cost of storage decreases be in accordance time; have equipment that is faster with better price. As a note the CPU and the memory to operate at speeds less than 20 nanosecond (10ˉ seconds), most of the secondary storage devices have access times in the distance mili second (10ˉ³ seconds) or close to millions of times more slowly from the main memory. When the computer must access the data warehouse on the secondary users have to wait longer than if the data in main memory.
Warehouse direct access to the tool's ability to store information be located anywhere in the warehouse direct access in roughly the same time. Warehouse direct access to the appropriate pilot warehouse, where all the data is arranged in the appliance and must be scanned in order to find specific information. Secondary tool shed the most rapid arranging semiconductor and does not have moved the section. Rotation and memory such as floppy disks slower and less reliable because of its mechanical components. We discuss the most popular type of secondary storage, magnetic disk.
Magnetic tape is one of the storage media is the oldest. Data stored in a series of ribbon; to get information back, we need to find the average half of the ribbon. Magnetic tape, and provide cheap off-line storage and backup that matches.
One of the latest storage equipment is the optical disk. At this time, this disk to load hundreds of millions of characters on the plates can be moved like a compact disk audio. There are a few of the optical disk; can given out, CD-ROM, and worms. Worm (write once, read many = write once, read many) disk and CD-Rom that permission the user to write information that can not be changed, the user can read the data repeatedly times. As the disk that is used intensively in the picture processing system where the document is scan and the digitized image "burned" in the optical disk. Type of storage (warehouse) is good for some historical data such as statistics on the stock market or on-line encyclopedia. So that storage can be useful for general purposes; optical disk can be removed several times, such as the use of drives available and wide spread in the following years.
To use the notebook and sub-notebook computers, the computer industry has developed a small card that can be filled into the contact on the engine stop this. This type of storage called a PCMCIA card. Unfortunately, there are three differences from the felt and all this card is only compatible with the direction on the (type II stop contact will take the card type I, but not vice versa). Each release of a sequence has been changed slightly larger to accommodate more functions. For example someone can buy a modem on the card. To three types of cards, the most bold this sat, will be used for miniature hard disk.
Technology has improved to obtain a trend that important, would help to see the difference in the computer generation that has passed. Because only the first 20 years produced Mainframe computers, Mainframe we discuss in the previous chapter that introduces the difference between PC and Mainframe modern computer.
Figure 8-4 shows the general model of Mainframe computers. One important difference between computer Mainframe and personal computer is not the bus architecture. Mainframe equipped with the most direct connection between the CPU and memory, the data does not pass, and proceeded to skip the bus. Bus architecture with modules more easily seen from the tools for connection to a different bus. In the previous bus architecture Mainframe more slowly and require direct connection to the speed.
Mainframe computer specialty starts with a processor. Mainframe is now common use of a series of commands (a series of commands that are generally dedicated and regulated by the seller) and the software that has a variety of processors. Various tiger-processor for the right owner of architecture vendors like IBM is relatively small, the order for 2 or 4 per computer.
In order to maintain the role of the Mainframe and to give strength processing that some applications need, computer companies are in the process of re-found Mainframe. The idea is to create a Mainframe-class machine that is issued from a number of chip cheap. For example, Mainframe-class computer from Hewlett-Packard (HP) and a group of DEC features of microprocessor quickly as opponents of the draft common Mainframe IBM 370 processor architecture. HP and DEC machines sell about $ 10,000 million instructions per speed per second (MIPS) compared with the IBM Mainframe to $ 30,000 to $ 80,000 per MIPS.
Mainframe computer organization using a common process large amounts of data. Computers may be able to access a database with billions of character data and manage hundreds or thousands of network terminals. As a result, the computer needed to be able to handle many activities and operations of communication input / output.
Mainframe channel usually has the data, which has the same power with the CPU on a computer that is smaller. Channels receive the data from the CPU, for example, take back the data from the disk file. While the data channel is busy the CPU to continue other work. channel when the data is complete, then interrupt the CPU that data is available. CPU and me to restart the program has been on the sidelines that this program is more important and higher than in the other program is waiting to run.
Only with the personal computer, the unit served on Mainframe computers to connect, in this case the data channel with the tools and save the I / O is different. This architecture has created Mainframe computers are very fast, which is used in the database, processing command, and other applications that count.
Brief history
Computer experts often expressed about the generation of a different computer, the general faithful generations together to introduce new computer hardware dean Technology clearly different with the earlier. Generation of succession has also been on the mark with a dramatic change in appearance. Each new generation has proven the increase of fast calculation speed and save more with a price lower than the equipment used. Generation computer can also be a characteristic change in the software; in chapter 8 we discuss the characteristics of the software in each generation.
Computer generation in the first component with a characteristic vacuum-tube (vacuum cleaner tubes) and rotation memory. One of the most popular models such as the IBM 650.
Second-generation computers use components for the center transistor processing unit and for the magnetic core memory. Channel data appear in this generation, in line with specific features to increase the CPU speed. Computer system used in the first commercial on-line communication and involving the division of time for the system, where users are given the ability to count through the terminal.
Third-generation hardware in the computer with the more characteristics of a large number of circuits and monolithic mini direction (the number of electronic components on the chip) to the center processing unit. Many features of the CPU is added to improve the work in this generation. Three-generation engine to make it easier to improve on-line applications that require telecommunications capabilities.
Developing the third generation to generation in the three and a half through the use of Technology for semiconductor memory in some of the main engine. The concept developed from the time the so-called "virtual memory" was also implemented through a special hardware facilities. (see part of the virtual memory on the next chapter)
Generation of computers to the four characteristics by the very large, a fast semiconductor memory, small size, and the needs of smaller energy. Fourth-generation engine is designed to facilitate the development of applications on-line facilities and the use of a large database.
Warehouse secondary
Generally refers to the secondary storage devices that store must be accessed through the data channel or bus; CPU can not carry data or commands directly from the equipment saving. There are several reasons why the use of secondary storage. First, we are often not able to have enough main memory to process data in large numbers. Some applications have a file which contains billions of character data, and can be a burden beyond the capacity of main memory is available at this time.
Although we have enough main memory and the physical can burden with on our computer, we will not want to fill it with data! Many programs use the main memory, each processing the data. If we always save all the data for one application in memory, then we have to give computer all or part of a special computer just for that application. Therefore, we do not want to store data that is not needed in main memory. Secondary storage devices provide a flexible capability storage for data and programs.
In general, the cost of storage decreases be in accordance time; have equipment that is faster with better price. As a note the CPU and the memory to operate at speeds less than 20 nanosecond (10ˉ seconds), most of the secondary storage devices have access times in the distance mili second (10ˉ³ seconds) or close to millions of times more slowly from the main memory. When the computer must access the data warehouse on the secondary users have to wait longer than if the data in main memory.
Warehouse direct access to the tool's ability to store information be located anywhere in the warehouse direct access in roughly the same time. Warehouse direct access to the appropriate pilot warehouse, where all the data is arranged in the appliance and must be scanned in order to find specific information. Secondary tool shed the most rapid arranging semiconductor and does not have moved the section. Rotation and memory such as floppy disks slower and less reliable because of its mechanical components. We discuss the most popular type of secondary storage, magnetic disk.
Magnetic tape is one of the storage media is the oldest. Data stored in a series of ribbon; to get information back, we need to find the average half of the ribbon. Magnetic tape, and provide cheap off-line storage and backup that matches.
One of the latest storage equipment is the optical disk. At this time, this disk to load hundreds of millions of characters on the plates can be moved like a compact disk audio. There are a few of the optical disk; can given out, CD-ROM, and worms. Worm (write once, read many = write once, read many) disk and CD-Rom that permission the user to write information that can not be changed, the user can read the data repeatedly times. As the disk that is used intensively in the picture processing system where the document is scan and the digitized image "burned" in the optical disk. Type of storage (warehouse) is good for some historical data such as statistics on the stock market or on-line encyclopedia. So that storage can be useful for general purposes; optical disk can be removed several times, such as the use of drives available and wide spread in the following years.
To use the notebook and sub-notebook computers, the computer industry has developed a small card that can be filled into the contact on the engine stop this. This type of storage called a PCMCIA card. Unfortunately, there are three differences from the felt and all this card is only compatible with the direction on the (type II stop contact will take the card type I, but not vice versa). Each release of a sequence has been changed slightly larger to accommodate more functions. For example someone can buy a modem on the card. To three types of cards, the most bold this sat, will be used for miniature hard disk.
Equipment I/O
Computer to process data in the size of the billions per second, in the appeal is with the internal speed of this, getting data to and from the computer is very slow.Input and output
Keyboard most users interact directly with the system, using the keyboard when the computer provides the input. Many of the interaction is completed through a terminal "dumb", a terminal that is able to send and receive data from the computer. Computer usually Mainframe or mini computers, and the terminal has a logic of the hardware which is very small, which can only display the data processing is not.
PC as the terminal increases, personal computers have been used as a terminal. Running programs that overlap, a terminal that makes the PC appear as a terminal, working with the computer itself. Why use the power of personal computers for a simple application? There are several reasons. First, the user has a personal computer on his desk to work, make it as a terminal means that only one tool is required. It is also possible, using a slightly different program to download data from the Mainframe or mini computer so that data can be analyzed using the program on a personal computer. These companies also distribute some processing for the application to your PC, for example, they may have a personal computer that provides the user equipment data and send data to the Mainframe. In the client server environment, users interact directly with the server using the full capability with their local workstation.
PC as the terminal increases, personal computers have been used as a terminal. Running programs that overlap, a terminal that makes the PC appear as a terminal, working with the computer itself. Why use the power of personal computers for a simple application? There are several reasons. First, the user has a personal computer on his desk to work, make it as a terminal means that only one tool is required. It is also possible, using a slightly different program to download data from the Mainframe or mini computer so that data can be analyzed using the program on a personal computer. These companies also distribute some processing for the application to your PC, for example, they may have a personal computer that provides the user equipment data and send data to the Mainframe. In the client server environment, users interact directly with the server using the full capability with their local workstation.
Input equipment only
Bar coding is a way to enter data in the computer that is very popular. We are facing something of bar coding in the buttery, which is outside the scanner. This tool use the laser to read the universal product code (UPC product code = universal) that goods be stamped on food materials. Tool laser bar code to read and translate it into a product identifier. The computer will see the price of goods and indicated burden on the display. Readers of a similar type used in other types of stores to mark items. Advantage of the predictive tool is the seller can keep the line inventory, sell auto and same time.
Type of bar code is used intensively in industrial factories. Factory in a very automated, each section marked with a bar code, the code govern the flow through the factory and even indicated to engine operation should be run. The use of bar coding can reduce the very human needs of the factory through the command line and keep the process working location, the form of labor does not directly.
OCR optical character recognition (optically recognize characters) is the technical input is important. Now this scan OCR and image the two of them sometimes known as "scanning." Discussion technical, scanner usually recognize the letters in the document and to change it in ASCII code as computer. You can move the results of the scan directly into a word document processing and can change.
Scanner equivalent very difficult to recognize handwriting input; most scanner works well on the printed document. To identify the letters or characters, the input scanner with character sets that are saved, try to find the most suitable. This task is far easier for the characters to print some of the standard; cause of hand in many different cases! There are opportunities for savings and labor cost if scanner can recognize handwriting. Consider its impact on the post office if the engine can read 75% hand zip code in the mail.
OCR saves the input data typing; someone can take the information that is not on the machine can read the form and to avoid typing back. As someone who may think, as a suspect strength, recognize the letters that require much less storage compared to examine the pictures. For example, the first edition of this book was written before the existence of a word processor; work to reduce and speed up production of the next edition, the publisher of scanning the original script and the script modifications so the text should not be typing back. Only changes in handwriting, which can not be scanned, it must be typing manual.
Imaging (image) image scanning system is used for desktop publishing based on the personal computer. Users can scan photos, drawings and other material and save it to your page. Computer does not try to understand what is scanned; transfer only an image from one medium to another medium.
Tool pictures (image) using a laser to digitize the input from the sheet of paper. Image on paper can be thought as something that appear by thousands of dots, 300 dots-per-an-inch (DPI = dots per inch). In the computer, each point indicated in the memory location information in line with the union. For example, if the scanner is able to display a gray shadow, this should save information about the strength of that point also. Imaging system (picture) does not recognize the characters but this system capable to make special processing; image as an image on page. You can not input image directly into the package to modify processing word document that you have scan.
Some pen pen-top personal computers has been introduced in the market. Users working with the pen to print the characters or match box on a form. This tool is for people who do not like the type that requires the application and can be moved-moved. Until now they have been successfully serving the people as an introduction to the aims for the record. Counts pen-top never tried used extensively for applications managerial.
Why not write instead of type?
Detroid Edison using pen-based PC to try to reduce the cost of cutting trees near power lines is $ 1 million a year. Cleaning path uses a pen to give the tree its personal and group based computer; goal of this project is to reduce the paper to the operation.
Supervisors benefit the use of pen-top computer while they review the benefits of one million polar-polar and millions of trees that they raised. Supervisors complete the work using the electronic pen to complete the forms in the computer screen. Input data envelop the location of the work, the type of line, and branches that should be regulated.
This information is stored on the memory card and PCMCIA input to form a database. A separate program to collect the work the contractor tree; check each contractor is given a computer and a PCMCIA memory card to work in accordance with the command. At the end of the work, a contractor to complete the electronic invoice which exhibit time and materials. Management change in the invoice and Detroit Eddison processing to adjust to the payment without any data.
This application is the best example of the use of Technology for a big job to write the writing. Detroit Eddison need system description does not cost; clever use of the Technology of the cheaper alternative to their work.
Soothsayer predict that voice input voice can change the way we work with computers. Now this voice input supply system in general is very limited. This system is usually used to enter the addresses in the packet on the line or short section classification. Basically the system to recognize a few words of greeting, and allow both hands free to users working at the time.
Follow-up the voice recognition is a difficult challenge. The computer must analyze and identify the utterance of words. System previously described is a system separate words, the user must maintain the pause between the words. introduction of continuous speech, is not required to stop a moment. System greeting going concern demanding a larger vocabulary than a separate system, and language speech has two meanings cause additional difficulty. What is the meaning of "time fly like arrow"? the emergence of sustainable introduction speech actually alter dramatically the way we interact with computers, but we have not at one with this Technology in the future.
Technology touch screen provides a good alternative for the user when the keyboard to enter data is limited. Clink with her finger to the screen, the user identifies what the options of interest. Bank can use the touch screen for ATM. Factory has a touch screen for an operator to set the engine on the test quality control. American Stock Exchange using the touch screen to enter some type of quote. Suitable type of input this information when there are a number of small to be entered, especially when not using the keyboard.
User PC mouse often works with an input which is called a mouse, the cursor around the screen command; pressing the button on the mouse to send commands to the programs. Mouse is an important part of the path from the Apple Macintosh computer. Communicator of this machine show objects on the screen called the icon, place the cursor on an icon and press the button on the mouse to select items, to the command is marked with the icon. Type communicator is called object-oriented (object oriented) and this tool has increased with the popular.
Equipment output
Tools laser printer output is most appropriate for the computer is personal laser printer. The tool is generally printed with resolution 300 DPI output quality and generate letters. laser print process is similar to the Technology and print photocopy this laser-quick if just than with alternative techniques get for hard-copy output from the computer. Minis and Mainframe also laser print can use, this high-speed equipment to print (print) 30 to 40 pages per minute; more output from the computer processes the transaction is completed using a laser print. Laser offers a variety of sizes and types of print and produce high quality output.
impact printer (impact printer) impact printer that is found in many PC tend to be cheaper than laser printers. Dot-matrix printer to make prints of actual on paper; a hammer to press against the ribbon cable to print a character. The more cable in the matrix, the higher the quality of printing characters. Impact printer that actually have other characters such as bullet typewriter. High speed impact printer to print the 2000 Mainframe strength lines per minute. For personal computers, printers impact more slowly than the laser printers, impact printers but much cheaper than laser printers.
Printer non impact printer is a laser printer that produces non impact one page at the same time. There are other printers that show non impact Technology diversity. One type of jet printers eject ink on the paper to form characters. Printer non impact another using thermal paper (related to heat) and produce characters with enrage point to display the characters.
Output voice vote suit has been available for many years. Bank sometimes provides on-line question about the balance sheet accounts, reconcile the bank account number, then someone generate audio feedback from the bank account balance. Sound output is used for information-intensive phone. Indicated information service number displayed on the terminal is a valid number, and the computer voice response. Free service for the call the other while playing the first message.
Graphic User personal computers often use their machines to prepare the presentation. Tool output light display computer graphics into the presentation output. The tool used is simple plotter, drawing plotter text and images on paper or transparency for presentation. To produce a 35mm view, the tool output to be able to copy the screen image on the film fotografic.
Reducing I / O bottleneck
There are diverse techniques of output / input to the computer. Although the diversity of I / O is often boring. Most of the information into the computer is done with drop, and possibly the world populated by two types of people that is not a typist and typist. Alternative form, such as sound, object-oriented, touch screen and offers a way to encourage the use of computers. One important trend is to reduce the amount of manpower involved in the input; bar coding and electronic exchange of information both serve to reduce the input of labor.
CHAPTER SUMMARY
Electronic computers have been increasing with the value that does not make sense. Now, this desktop computer has more power than the first generation of computer fills every room. Cost of computer hardware continues to decline as a breakthrough in the continuation of the computer component manufacturing. Computer users have plenty of different to choose from. As additional, there are a variety of Technology to supply input data to a computer, to store data, and to show output of the engine. Manager a need to understand some of this alternative in order to evaluate and select the IT architecture for the company when designing a specific IT application.
There are diverse techniques of output / input to the computer. Although the diversity of I / O is often boring. Most of the information into the computer is done with drop, and possibly the world populated by two types of people that is not a typist and typist. Alternative form, such as sound, object-oriented, touch screen and offers a way to encourage the use of computers. One important trend is to reduce the amount of manpower involved in the input; bar coding and electronic exchange of information both serve to reduce the input of labor.
CHAPTER SUMMARY
Electronic computers have been increasing with the value that does not make sense. Now, this desktop computer has more power than the first generation of computer fills every room. Cost of computer hardware continues to decline as a breakthrough in the continuation of the computer component manufacturing. Computer users have plenty of different to choose from. As additional, there are a variety of Technology to supply input data to a computer, to store data, and to show output of the engine. Manager a need to understand some of this alternative in order to evaluate and select the IT architecture for the company when designing a specific IT application.
