CD-R (compact disk-recordable)

A temporary storage area, usually in RAM. The purpose of most buffers is to act as a holding area, enabling the CPU to manipulate data before transferring it to a device. Because the processes of reading and writing data to a disk are relatively slow, many programs keep track of data changes in a buffer and then copy the buffer to a disk. For example, word processors employ a buffer to keep track of changes to files. Then when you save the file, the word processor updates the disk file with the contents of the buffer. This is much more efficient than accessing the file on the disk each time you make a change to the file. Note that because your changes are initially stored in a buffer, not on the disk, all of them will be lost if the computer fails during an editing session. For this reason, it is a good idea to save your file periodically. Most word processors automatically save files at regular intervals. Another common use of buffers is for printing documents. When you enter a PRINT command, the operating system copies your document to a print buffer (a free area in memory or on a disk) from which the printer can draw characters at its own pace. This frees the computer to perform other tasks while the printer is running in the background. Print buffering is called spooling. Most keyboard drivers also contain a buffer so that you can edit typing mistakes before sending your command to a program. Many operating systems, including DOS, also use a disk buffer to temporarily hold data that they have read from a disk. The disk buffer is really a cache.
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A system that randomly generates a private key, and is used only once to encrypt a message that is then decrypted by the receiver using a matching onetime pad and key. Onetime pads have the advantage that there is theoretically no way to “break the code” by analyzing a succession of messages. Manual onetime cryptosystem produced in pad form.
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A compact disk, similar to an audio compact disk, which is used to store computer information (e. g. , programs, data, or graphics).
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A token device that generates onetime passwords after the user enters a PIN in the token device. The PIN is provided by a server as a challenge, and the user enters the onetime password created by the token as the response.
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Disk mirroring protects data against hardware failure. In its simplest form, a twodisk subsystem would be attached to a host controller. One disk serves as the mirror image of the other. When data is written to it, it is also written to the other disk. Both disks will contain exactly the same information. If one fails, the other can supply the user data without problem.
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