Peripheral devices, computer

A computer must communicate with a variety of peripheral devices (keyboard, mouse, printer, mass spectrometer). A central processing unit (CPU) controls the flow of information to each, rather like a choreographer directing complicated dance routines. 

Host computers. These are the most powerful computers in the system, capable of performing func tions not normally available in other units. They act as the arbitrator unit to route internodal communications. An operator interface is supported and various peripheral devices are coordinated. Computationally intensive tasks, such as optimization or advanced control strategies, are processed here. 

Industrial process furnaces and ovens Mechanical powertransmission equipment, n.e.c. General industrial machinery and equipment, n.e.c. Electronic computers Computer storage devices Computer terminals Computer peripheral equipment, n.e.c. Calculating and accounting machines, except electronic computers Office machines, n.e.c. ... 

In distributed systems, each participating site must be equipped with a desktop or a laptop computer loaded with the distributed data collection system software to collect and enter data locally. In addition, each site is provided with necessary storage devices such as tapes, zip diskettes, and CDs and peripheral devices such as printers. Collected data are transferred periodically to the central location as files saved on storage devices, via phone modems, by FTP, or through wireless communications, where they are managed by a centralized data management system. 

A Fourier transform infrared spectroscopy spectrometer consists of an infrared source, an interference modulator (usually a scanning Michelson interferometer), a sample chamber and an infrared detector. Interference signals measured at the detector are usually amplified and then digitized. A digital computer initially records and then processes the interferogram and also allows the spectral data that results to be manipulated. Permanent records of spectral data are created using a plotter or other peripheral device. 

The following process is applicable for changes to any component of computer technology that performs functions on regulated products, including hardware, peripheral devices, system software and utilities, application software, documentation, and communications hardware and software. These components can be either purchased from an external supplier or developed in house by the company or its designee. 

All types of computer hardware and software are used for Internet communication. Because these are typically used in regulated environments, we could assume that all such computer hardware, peripheral devices, and software should be validated. However, because of the nature of the Internet this is umealistic. 

Network GAMP (2001) A network is a data communications system that links two or more computers and peripheral devices. It consists of cabling, the network hardware, and communications software. 

For some ports, the computer s operating system—the ROM which controls the machine s functions—provides routines that handle much or all of the "dirty work" of communicating with peripheral devices. To use other ports, you must program all the necessary support routines yourself. That task can range from very easy (for example, reading a joystick) to quite complex (interfacing with a parallel printer through the user port, for example). 

Obviously, this port is bidirectional—data can flow both in and out with equal ease. The signal format used to exchange data serially over the six lines provided through this port is unique to Commodore. The format should not be confused with the more standard RS-232 serial communications format used by numerous peripherals RS-232 communication is handled through the user port (see below). The serial port is essentially a stripped-down version of the parallel IEEE-488 port used for most data communications in Commodore s earlier PET/CBM models. As the term serial implies, data can be transferred only one bit at a time (and in only one direction at a time, either in or out). Three of the other lines control the direction of data flow, and whether the signals on the data line are to be interpreted as data or as commands to the peripheral device. The computer s RESET line is also present at this port, which explains why the disk drive resets whenever the computer is turned on or off. 

Modems (MODulator/DEModulators) are the devices that computers use to talk to one another over phone lines. They can be considered a type of output device because they move data out of the computer to another device. Modems work by converting digital signals (binary Is and Os) into analog signals (tones over a phone line), and vice versa. Modems are added to a computer either as an external device or as an expansion card installed inside the computer. Internal modems are usually less expensive than external modems, but external modems are easier to troubleshoot than internal modems because you can see the lights that indicate what is happening. Lor more information on modems, see Chapter 6, Peripheral Devices. ... 

One disadvantage to the serial mouse is that it uses a COM port. If the computer had only one COM port, that was it— you couldn t use any other peripheral devices. Also, if you had another COM port but it was on a shared interrupt, that other COM port couldn t be used for another communication device (like a modem) as long as data was coming into the computer on the COM port being used by the mouse. So, in a manner of speaking, a serial mouse really takes up two COM ports. For example, because COM 1 and COM 3 both share Interrupt 4, when you put a mouse on COM 1 you are also preventing the use of COM 3. 

RS-232-C In asynchronous transmissions, a recommended standard interface established by the Electrical Industries Association. The standard defines the specific lines, timing, and signal characteristics used between the computer and the peripheral device and uses a 25-pin or 9-pin DB connector. RS-232-C is used for serial communications between a computer and a peripheral such as a printer, modem, digitizing tablet, or mouse. 

SCSI Acronym for small computer system interface. A high-speed, system-level parallel interface defined by the ANSI X3T9.2 committee. SCSI is used to connect a personal computer to several peripheral devices using just one port. Devices connected in this way are said to be daisy-chained together, and each device must have a unique identifier or priority number. 

USB Acronym for Universal Serial Bus. A technology used to connect peripheral devices to a computer. Each USB channel will support 127 devices and has a total transfer rate of up to 12MBps. 

Any device connected to the computer but not essential for its basic operation can be called a peripheral device. Peripherals also may be regarded as those devices connected to the computer via a cable. With the possible exception of the hard drive that contains the operating system, most storage devices can be regarded as peripherals. Other peripherals include printers, scanners, cameras, and other devices for getting data in or moving data out, typically called input/output devices or I/O devices. 

FIGURE 4[Pg.93]

The central processing unit (CPU) controls the overall operation of the computer. It is made up of electronic registers and logic circuits that execute the simple logical and arithmetic operations of which the computer is capable. When these operations are executed in appropriate sequences, the computer can accomplish complex mathematical or data-processing functions. Moreover, if one provides the appropriate electronic interface, these simple operations can be used to control experimental systems, acquire data, or print results on a teletype printer, line printer, oscilloscope, or other peripheral device. 

The different components of a computer, its memory, and the peripheral devices, such as printers or scanners, are joined by buses. To guarantee rapid communication among the various parts of a computer, information is exchanged on the basis of a definitive word size, for example, 16 bits, simultaneously over parallel lines of the bus. A data bus serves the exchange of data into and out of the CPU. The origin and the destination of the data in the bus are specified by the address bus. For example, an address bus with 16 hues can address 2 = 65536 different registers or other locations in the computer or in its memory. Control and status information to and from the CPU are administrated in the control bus. The peripheral devices are controlled by an external bus system, for example, an RS-232 interface for serial data transfer or the IEEE-488 interface for parallel transfer of data. 

Peripheral devices (e.g., client-server desktop user interface computers, printers and backup devices)... 

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