Architecture
(n.) A design. The term architecture can refer to either hardware or software, or to a combination of hardware and software. The architecture of a system always defines its broad outlines, and may define precise mechanisms as well. An open architecture allows the system to be connected easily to devices and programs made by other manufacturers. Open architectures use off-the-shelf components and conform to approved standards. A system with a closed architecture, on the other hand, is one whose design is proprietary, making it difficult to connect the system to other systems.
Kernell
The central module of an operating system. It is the part of the operating system that loads first, and it remains in main memory. Because it stays in memory, it is important for the kernel to be as small as possible while still providing all the essential services required by other parts of the operating system and applications. Typically, the kernel is responsible for memory management, process and task management, and disk management. Shell
(1) The outermost layer of a program. Shell is another term for user interface. Operating systems and applications sometimes provide an alternative shell to make interaction with the program easier. For example, if the application is usually command driven, the shell might be a menu-driven system that translates the user's selections into the appropriate commands.(2) Sometimes called command shell, a shell is the command processor interface. The command processor is the program that executesoperating system commands. The shell, therefore, is the part of the command processor that accepts commands. After verifying that the commands are valid, the shell sends them to another part of the command processor to be executed.
UNIX systems offer a choice between several different shells, the most popular being the Cshell, the Bourne shell, and the Korn shell. Each offers a somewhat different command language.
Buffer
(n.) 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 savethe 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 computerfails 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.
Buffers are commonly used when burning data onto a compact disc, where the data is transferred to the buffer before being written to the disc.
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 driversalso 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.
(v.) To move data into a temporary storage area.
Spooler
A program that controls spooling -- putting jobs on a queue and taking them off one at a time. Most operating systems come with one or more spoolers, such as a print spooler for spooling documents. In addition, some applications include spoolers. Many word processors, for example, include their own print spooler. A good print spooler should allow you to change the order of documents in the queue and to cancel specific print jobs.
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