![]() ![]() IEEE 802.5 : Standards for token ring access and for communications between LANs and MANs IEEE 802.4 : Standards for token passing bus access. IEEE 802.3 : Ethernet Standards for Carrier Sense Multiple Access with Collision Detection (CSMA/CD). IEEE 802.2 : Standards for Logical Link Control (LLC) standards for connectivity. IEEE 802.1 : Standards for LAN/MAN bridging and management and remote media access control bridging. Delayed versions of time (a chip or later) of the signal (multipath signals) can be collected and used to make decisions at the bit level. Rake receivers can be used to improve signal reception. All signals must have more or less equal power at the receiver In other words, a user near the base station transmitting with the same power will drown the signal latter. It has the following advantages −ĬDMA requires a tight power control, as it suffers from near-far effect. The greater the number of codes, the more the number of users. Using a group of codes, which are orthogonal to each other, it is possible to select a signal with a given code in the presence of many other signals with different orthogonal codes.ĬDMA has a soft capacity. A code called spreading code is used to perform this action. Here, a signal is generated which extends over a wide bandwidth. ![]() Techniques generally used are direct sequence spread spectrum modulation (DS-CDMA), frequency hopping or mixed CDMA detection (JDCDMA). Ĭode- division multiple access ( CDMA) is a channel access method used by various radio communication technologies.ĬDMA is an example of multiple access, where several transmitters can send information simultaneously over a single communication channel. Lack of history for such attributes can limit the level of analysis that can be performed on the data. Generally history for such attributes would not be preserved, which results in loss of historical data. For ex employee address, product name, martial status etc. Lack of historical data can limit the level of analysis that can be performed on the data.Ĥ) OLTP systems tend to store most updated version of data only. It might be in the form of hard / soft delete. For reporting and analysis purposes over a very huge dataset spanning thousands to millions of records of historical data, such queries would perform very poorly.ģ) OLTP systems tend to archive data time to time on a scheduled basis. This means that reading this data requires creating joins with many tables. This makes designing queries harder for reporting purposes.Ģ) As normalised schema has a lot of tables, a single piece of related information is split and stored into various tables with referential integrity constraints. OLTP systems have a probability, that a portion of these tables can be often less descriptive due to lack of self relevant naming conventions. The VFS layer translation translates the non-file system specific calls into a file system specific operation.ġ) Data stored in normalized schema in OLTP systems can have hundreds to thousands of tables for an enterprise. The program that is used for calling does not have a file system specific code also the system call structures used in upper levels are file system independent. ![]() The VFS layer translates a system call into the correct specific functions for the targeted file system. Any file system that is used gives its function calls used and the data structures to the layer of VFS. The VFS layer enables the OS to make system calls independent of the file system type used. It acts like an abstraction layer on top of a more specific file system. The VFS layer translation translates the non-file system specific calls into a file system specific operation.The VFS layer also known as the virtual file system functions in many ways similar to object oriented programming techniques. The VFS layer also known as the virtual file system functions in many ways similar to object oriented programming techniques. ![]()
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