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I-Terms
LPD: (Line Printer Daemon) A TCP/IP printer protocol that provides print spooling and network printing. Originally developed for Berkeley UNIX (BSD UNIX), LPD has become the de facto cross-platform printing protocol. LPD and its LPR (Line Printer Remote) client counterpart are often referred to as the LPR/LPD protocol. The LPD software can reside in a computer that serves as the print server or within the printer itself, and most network printers have built-in LPD support. The LPR software must be installed in the client machine, and the LPR client sends its printer output to the IP address of the LPD printer (LPD server), which queues the files and prints them when the printer becomes available. LPD servers can support
multiple printers, in which case, the LPR client identifies the intended printer by its queue name. If the operating system does not support LPR/LPD, it must be installed from a third party.
Clock cycle: In a computer, the clock cycle is the time between two adjacent pulses of the oscillator that sets the tempo of the computer processor. The number of these pulses per second is known as the clock speed, which is generally measured in MHz (megahertz, or millions of pulses per second) and lately even in GHz (gigahertz, or billions of pulses per second). The clock speed is determined by a quartz-crystal circuit, similar to those used in radio communications equipment. Some processors execute only one instruction per clock cycle. More advanced processors, described as superscalar, can perform more than one instruction per clock cycle. The latter type of processor gets more work done at a given clock speed than the former type. Similarly, a computer with a 32-bit bus will work faster at a given clock speed than a computer with a 16-bit bus. For these reasons, there is no simple, universal relation among clock speed, “bus speed,” and millions of instructions per second (MIPS).
SMP: Symmetric multiprocessing is the processing of programs by multiple processors that share a common operating system and memory. In symmetric (or “tightly coupled”) multiprocessing, the processors share memory and the I/O bus or data path. A single copy of the operating system is in charge of all the processors. SMP, also known as a “shared everything” system, does not usually exceed 16 processors. SMP systems are considered better than MPP systems for online transaction processing (OTP) in which many users access the same database in a relatively simple set of transactions. An advantage of SMP for this purpose is the ability to dynamically balance the workload among computers (and as a result serve more users faster).
Hotfix: In Microsoft products, a hotfix is code (sometimes called a patch) that fixes a bug in the product. Users of the products are typically notified or can obtain information about current hotfixes at Microsoft’s Web site and download the hotfixes they wish to apply. Hotfixes are sometimes packaged as a set of fixes called a combined hotfix or a service pack. Quick Fix Engineering (QFE) is a newer Microsoft term for a hotfix.
Sequential access: Refers to reading or writing data records in sequential order, that is, one record after the other. To read record 10, for example, you would first need to read records 1 through 9. This differs from random access, in which you can read and write records in any order. Some programming languages and operating systems distinguish between sequential-access data files and random-access data files, allowing you to choose between the two types. Sequential-access files are faster if you always access records in the same order. Random-access files are faster if you need to read or write records in a random order. Devices can also be classified as sequential access or random access. For example, a tape drive is a sequential-access device because to get to point q on the tape, the drive needs to pass through points a through p. A disk drive, on the other hand, is a random-access device because the drive can access any point on the disk without passing through all intervening points.
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