Secondary Storage

译文：传统的软盘是2HD 1.44MB32英寸磁盘。2HD表明两面高密度的磁盘。磁盘打开百叶窗，提供访问记录表面、标签记录磁盘内容和写保护等级允许或禁止写入磁盘。
Files are stored and organized according totracks(concentric circles) andsectors(wedge shapes).
Three types of hard disks are internal hard disks, hard-disk cartridges, and hard-disk packs.
译文：三种硬盘是内置硬盘、硬盘墨盒和硬盘秀。
Internal Hard Disk（内置硬盘）
Internal hard disksare located within the sys-tem unit and typically identified as the C drive.
译文：光碟机（CDs）通常有650MB和1GB的容量。三类型：只读光盘驱动器（com-pact disc-read-only memory）、可记录光盘驱动器（CD-recordable（可记录光盘驱动器也称为CD刻录机）和可复写式光盘机（compact disc rewritable, erasable optical discs）。
译文：内置硬盘位于在主机之内且通常确定为C驱动器。
Hard-Disk Cartridge（硬盘墨盒）
Unlike internal hard disks,hard-disk car-tridgesare removable and their capacity is lim-ited only by the number of cartridges.PC Card hard disksare for notebook computers.
译文：要成为一个有竞争的最终用户，你需要知道不同类型的辅助存储器。你需要知道它们的容量、局限性和用途。有四种广泛使用的存储媒介：软盘、硬盘、光盘和其他类型的辅助存储器。
HARD DISKS
（硬盘）
Compared to floppy disks,hard disksuse rigid metallic platters that provide much greater ca-pacity. Files are organized according totracks, sectors,andcylinders.
SECONDARY STORAGE
（辅助存储器）
STORAGE
（存储器）
RAM isprimary storage. Most RAM is volatile, meaning that it loses its contents whenever power is disrupted.Secondary storageprovides nonvolatile storage. Secondary storage retains data and information after the computer system is turned off.
译文：硬盘组是可移动的且有多个盘片和大量的容量。一个磁盘组通常有11盘20记录表面。
Performance Enhancements（性能提升）
Three ways to improve hard disk performance are disk caching,RAID,and file compression and decompression.
译文：随机存取存储器是主存储器。大多数随机存取存储器是易失的，这意味着每当电源中断时它失去它的内容。辅助存储器提供非易失性存储器。在计算机系统关掉后，辅助存储器保留数据和信息。
Writing is the process of saving information tosecondary storage devices. Reading is the process of accessing information from secondary storage devices.
译文：由于其存储容量有限，软盘和软盘驱动器不再广泛使用。
To be a competent end user, you need to be aware of the different types of secondary storage. You need to know their capabilities, limitations, and uses. There are four widely used storage media: floppy disk, hard disk, optical disc, and other types of secondary storage.
译文：三个方法提升硬盘性能：磁盘驱动器高速缓存、磁盘阵列及文件压缩和解压。
Disk caching------provides a temporary high-speed holding area between a secondary stor-age device and the CPU; improves perform-ance by anticipating data needs and reducing time to access data from secondary storage.
译文：磁盘驱动器高速缓存——提供一个暂时的高速的保存区在辅助存储设备和CPU之间；通过预期的数据需要和减少时间从辅助存储器访问数据来提升性能。
RAID (redundant array of inexpensive disks)------several inexpensive hard disk drives are connected together; improves perform-ance by providing expanded storage, fast ac-cess, and high reliability.
译文：媒介——实际的物理材料，保留数据和程序。
Capacity-------how much a particular storage medium can hold.
译文：容量——一个特殊的存储介质可以容纳多少。
Storage devices------hardware that reads and writes to storage media.
译文：磁盘阵列（redundant array of inexpensive disks）——数个便宜的硬盘驱动器连接在一起；通过扩展存储、快速访问和高可靠性来提升性能。
File compression and decompression------files mpressed before being used again; improves performance through efficient storage.
译文：写是保存信息到辅助存储器设备的过程。读是从辅助存储器设备获取信息的过程。
Important characteristics of secondary stor-age include
译文：辅助存储器的重要特征包括
Media------actual physical material that retains data and programs.
译文：光盘使用激光技术。1和0代表凹和凸。光盘驱动器项目的光线并且测量反射光。
Compact Disc（CD）
Compact discs (CDs)have typical capacity of 650MB to 1GB. Three types areCD-ROM (com-pact disc-read-only memory),CD-R (CD-recordable(CD-R drives are also known as CD burners)), andCD-RW (compact disc rewritable, erasable optical discs).
译文：大容量软盘（软盘盒）的容量比传统的软盘的大。最广泛使用的是压缩磁盘，典型的容量100MB、250MB和750M。
Due to their limited storage capacity, floppy disks and floppy disk drivers are no longer widely used.
译文：不象内置硬盘，硬盘盒是可移动的且其容量只由墨盒的数量是有限的。
Hard-Disk Packs（硬盘组）
Hard-disk packsare removable and have several platters and extensive capacity.A disk pack typi-cally has 11 platters with 20 recording surfaces.
译文：软盘是灵活的，圆形的聚酯薄膜涂塑磁性材料。软盘驱动器（FDD）存储数据和程序收取磁盘表面。
Traditional Floppy Disk（传统的软盘）
The traditional floppy disk is the 2HD 1.44MB3 1/2-inch disk.2HD indicates two-sidedhigh-densitydisk. Disks haveshuttersthat open to provide ac-cess to the recording surface,labelsto record disk content, andwrite-protection notchesto allow or prohibit writing to the disk.
译文：文件存储和组织根据磁道（同心圆）和扇区（楔形）。
High-Capacity Floppy Disks（大容量软盘）
High-capacity disks (floppy disk cartridges)have greater capacity than the traditional floppy disk. The most widely used are Zip disks, withtypicalcapacities of 100MB, 250MB, and 750MB.
译文：存储设备——硬件，存储介质读和写。
Access speed-------time required to retrieve data from a secondary storage device.
译文：访问速度——从辅助存储设备中检索数据所需的时间。
FLOPPY DISKS
（软盘）
Floppy disksare flexible that circular pieces of Mylar plastic coated with a magnetic material.Floppy disk drives (FDD)store data and pro-grams by charging the disk surface.
译文：与软盘相比，硬盘使用刚性的金属的大浅盘，提供更大的容量。文件组织根据磁道、扇区和圆柱体。
A head crashoccurs when the hard disk makes contact with the drive’s read/write heads.
译文：当硬盘与驱动器的读/写磁头接触，磁头碰撞发生。
译文：文件压缩和解压——在存储之前压缩文件和然后在再次使用前解压；通过高效的存储来提升性能。
OPTICAL DISCS
（光盘）
Optical discsuse laser technology. 1s and 0s are represented bypitsandlands.Optical disc drivesproject light and measure the reflected light.