高分跪求计算机英语第三版的第七单元课文B部分的英文原版或翻译!有的进!

高分跪求计算机英语第三版的第七单元课文B部分的英文原版或翻译!有的进!
高分 跪求 计算机英语 第三版 的 第七单元 课文B 部分communicating with other devices的英文原版或翻译!机械工业出版社 王春生版 有的进!有的再加50分!

Main memory and the CPU form the core of a computer. In this section,
we investigate how this core, which we will refer to as the computer,
communicates with peripheral devices such as mass storage systems,
printers, keyboards, mice, monitors, digital cameras, and even other
computers.
I. The Role of Controllers
Communication between a computer and other devices is normally
handled through an intermediary apparatus known as a controller. In the
case of a personal computer, a controller may consist of circuitry
permanently mounted on the computer's motherboard or, for flexibility', it
may take the form of a circuit board that plugs into a slot on the
motherboard. In either case, the controller connects via cables to peripheral
devices within the computer case or perhaps to a connector, called a port,
on the back of the computer where external devices can be attached.these
controllers are sometimes small computers themselves, each with its,own
memory circuitry and simple CPU that performs a program directing the activities of the controller
a controller translates messages and date back and forth between forms conpatible with the internal characteristics of the computer and those of the peripheral device to which it is attached. originally,each controller was designed for a particular type of device;thus,purchasing a new peripheral device often required the purchase of a new controller as well.
Recently, steps have been taken within the personal computer arena to
develop standards, such as the universal serial bus (USB) and FireWire,2
by which a single controller is able to handle a variety of devices. For
example, a single USB controller can be used as the interface between a
computer and any collection of USB-compatible devices. The list of devices
on the market today that can communicate with a USB controller includes
mice, printers, scanners, mass storage devices, and digital cameras.
Each controller communicates with the computer itself by means of
connections to the same bus that connects the computer's CPU and main
memory (Figure 7B-I). From this position it is able to monitor the signals
being.sent between the CPU and main memory as well as to inject its own.
signals onto the bus.
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With this arrangement, the CPU is able to communicate with the
controllers attached to the bus in the same manner that it communicates
with main memory. To send a bit pattern to a controller, the bit pattern is
first constructed in one of the CPU's general-purpose registers. Then an
instruction similar to a STORE instruction is executed by the CPU to
"store" the bit. pattern in the controller. Likewise, to receive a bit pattern
from a controller,an instruction similar to a LOAD instruction is used.