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电子信息类专业英语（第二版）李白萍主编
第五单元译文
第五单元
A
compact
disc
(CD)
is
a
laser-read
(also
termed
“
optically
read
”
)
data
storage
device on which audio, video, or
textual material can be stored. Although it has
been
used
primarily
to
record
stereophonic
sound
and
has
supplanted
the
long-playing
PHONOGRAPH
record
as
the
principal
medium
for
music
storage,
it
offers
a
huge
potential
as
the
medium
for
the
storage
of
massive
amounts
of
many
types
of
information.[1]
一个光盘（
CD
）是在其上的音频，视频或文本材料可被存储在激光读取（也
称为“光学读取”）数
据存储设备。虽然它被主要用来记录立体声声音，并已经
取代了留声机成为了主要的音乐
存储媒体，
但它作为能存储大量多种信息的媒体
仍具有巨大的潜
力。
Unlike the
conventional phonograph record, the CD stores
information in digital form.
Stereophonic
(two-channel)
sound
signals
are
digitally
sampled
at
a
rate
of
44,100
times
per
second
per
channel.
Each
sample
is
expressed
as
a
binary
number
value
consisting
of
16
binary
digits,
or
bits.
The
sampled
digital
values,
along
with
error
correction
data,
tracking
codes,
and
cueing
data,
are
recorded
on
a
digital
tape,
which is used to make compression-
molded plastic discs 12 cm (4.72
in) in diameter,
each
covered
by
a
thin,
reflective
metallic
layer
and
protected
by
a
clear
plastic
coating.[2] During playback, a low-
powered laser beam reads the digital data through
the reflective rear surface of the
disk.[1]
与传统的照片记录不同，光盘以数字形式
存储的信息。立体声（双声道）声
音信号以每秒
44,100<
/p>
次每信道的速率进行数字采样。每个样本被表示为二进制
数的值由
16
个二进制数位，或比特组成。样本数值，以及误差校正数据
，跟踪
代码和暗示的数据，记录在数字磁带上，它是用来制成直径为
12
厘米（
4.72
英
寸）
的压缩成形的塑料盘，
各由一个薄的、
反射性的金属层和一个透明的塑料涂
层保护。在播放过程中，低功率激
光束通过光盘表面的反射后读取数据。
The
CD
improves
over
conventional
records
and
tape
recordings
with
its
more
uniform
and accurate frequency response, a complete
absence of background noise,
a wider
dynamic range (the difference between the softest
and loudest recordable
musical sounds),
and longer wear
—
since
nothing mechanical touches the surface of
the disc when it is played.
光盘改善了传统的记录和录音
---
---
更均匀、
精确的频率响应，
完全
没有背景噪音，
更宽的动态范围（不同于最柔软的和最大可录制音乐地声音），而且更耐
用。因
为当它被播放时没有机械接触光盘的表面。
Introduced in 1992, the Sony MiniDisc
measures only 6.35
cm
(2.5
in) in
diameter,
but it can be used to record
as well as play up to 74 minutes of music. Its
small size is
made possible by a system
of data reduction that uses psycho-acoustic
principles to
eliminate data that is
not normally heard by the listener-thereby
reducing the data
density to one-fifth
that required for conventional CDs. Mini-Discs can
be used only
with their own recorder-
player.
引进于
1992
年的索尼迷你光碟直径仅
6.35
厘米（
2.5
英寸）长，但它可以被用
来记录以及播放长达
74
分钟的音乐。数据压
缩系统使光盘的小尺寸成为可能，
该系统利用心理声学原理来消除数据，
被听众聆听是不正常的。
因而通过降低数
据密度的五分
之一，需要对传统的
CDs
提出要求
.
迷你光盘只能在特定的录放机
中使用。
A
second
important
application
of
CD
technology
is
the
CD-ROM
(Compact
Disc
Read Only Memory), a
text/graphics/sound storage medium that is
accessed through
the CD-ROM drive in a
computer. A CD-ROM
can
store in excess of 500 megabytes
(millions
of
bytes)of
data
—
as
compared
with
a
computer
’
s
hard
disk,
whose
maximum
storage
capacity
is
about
200
megabytes.
(The
Academic
American
Encyclopedia was
the first encyclopedia to be made available as a
CD-ROM, in 1986).
New
data
compression
techniques,
which
can
filter
out
massive
quantities
of
unneeded data, have
expanded
CD-ROM
capacities
to
include
sound
and
image
as
well as text storage: in 1993 the first
movie (A Hard Day
’
s Night)
was recorded on a
CD-ROM .
CD
技术的第二个重要的应用是
CD-
ROM
（光盘只读存储器），一种通过在一台
电脑的
CD-ROM
驱动器访问的文本
/
图形
/
声音存储媒体。
与一个
电脑的硬盘最大
存储容量大约为
200
兆字节进行比较，
一个只读存储器能存储超过
500
兆字节的
数据（百万字节）。（美国百科全书是在
1986
年第一个被制成
CD-ROM
的百科
全书）。新的数据压缩技术，可以过滤掉大量不需要的数据，这扩大了
CD-ROM
的容量包括声音和图像以及文本存储；在
1993
年的第一部电影“艰难的一天一
夜”被记录的
CD-ROM
上。
The Interactive Compact
Disc, or CD-I, is essentially a CD-ROM that can be
accessed
via
a
CD-I
player
attached
to
a
television
set.
With
an
on-screen
cursor
and
a
handheld control pad the user can
choose his or her own path through a game, an
art
history
tour,
or
a
“
How
To
”
tutorial
that
includes
CD-quality
sound
and
thousands of full-color images as well
as text. Among the variation of the CD-I is the
Photo CD, which records still photos
digitally, for display on a TV screen. Improved
data compression techniques for video
will eventually allow movie storage on CD-Is,
with a quality comparable to
boy
’
s laser-recorded
videodiscs.
交互式光盘或
CD-1
，
基本上是一个
CD-R
OM
，
它可以通过
CD-1
播放机连接到电视
机。
利用屏幕上的光标移动和手
持式控制面板，
用户可以选择他或她自己的方式
访问光盘，通过
游戏，艺术历史之旅，或“如何做”的教程，教程包括
CD
质量
的声音和数以千计的全彩色图像和文本。其中
CD-1
的变化就是照片的
CD
，它记
< br>录静态照片的数字，
以显示在电视屏幕上。
改进的视频数
据压缩技术最终将允许
电影存储在
CD-
Is
上，那是可以和当今的激光记录视盘媲美。
Passage B
Hard Disks and Optical
Disks
硬盘和光盘
The
hard
disk
drive
provides
increased
storage
capabilities
and
faster
access.
Hard disks were
developed by IBM in 1973. The early ones were
extremely expensive;
however, with mass
production of
the personal computer, a
hard disk drive is now
available for as
little as $$200, and it is incorporated into the
computer system. A fixed,
hard disk
usually has one or more disk platters coated with
a metal oxide substance
that allows
information to be magnetically stored on it. This
storage system includes
the
disk,
a
read/write
head
assembly,
and
the
connections
between
the
drive
and
the computer.
硬盘
驱动器提供了增加的存储能力和更快的访问。
硬盘是由美国国际商用机
< br>器公司在
1973
年生产的。早期的硬盘极其昂贵
;
然而
,
大规模生产
的个人电脑
,
硬
盘驱动器现在仅售价为
200
美元
,
而且它纳入计算机系统。固态硬盘通常有一个
或多个涂有一层金属氧化物磁性物质的磁盘
,
使信息在它上面存储。这个存储系
统
包括磁盘、读
/
写磁头组件
,
驱动和计算机之间的连接。
At first, these disk drives used 14
inch disks, but now they use 5 1/4
inch, 3 1/2
inch,2 1/2
inch,
and 1 4/5
inch diameters. In
contrast to the floppy disk drive, hard
disk drives hold from 80 megabytes to
gigabytes and terabytes of information. When
purchasing a hard disk, consider
storage capacity and seek time, a measure of a
hard
disk
’
s
access speed. The smaller the numbers, the faster
the disk. In the past, 65
milliseconds
was
the
standard
access
time,
but
today
the
standard
is
less
than
7
milliseconds.
起初
,
这些磁盘驱动器使用
14
英寸的磁盘
,
但现在他们使用
5
1/4
英寸
,3
1/2
英寸
,2
1/2
英寸
,14/5
英寸直径的
磁盘。与软盘驱动器相反，硬盘驱动器拥有从
80
字节到千兆字
节和兆兆字节的信息。购买硬盘时
,
考虑存储容量和寻道时间用
来衡量硬盘的访问速度。数字越小
,
硬
盘访问速度越快。在过去
,65
毫秒是标准的
< br>访问时间
,
但是今天这个标准小于
7
毫秒。
How Is Data Stored on a
Hard Disk?