Summarize the purpose of the SQL language. Compare writing SQL commands with using a graphical user interface, GUI (such as the one used by Access). Which would you prefer, and why do you think it is important to understand both approaches?

Consider a slotted aloha system, where the time slot equals the fixed duration of each packet. assume that there are 4 stations a,b,c,d sharing the medium. (a) stations a,b,c,d receive one packet each from higher layers at times 1.3, 1.5, 2.6,5.7 respectively. show which transmissions take place when, according to the slottedaloha protocol; describe all transmissions until all four packets have been successful.when needed, each station has access to the following sequence of random number, provided by a random number generator and drawn uniformly between 0 and 1: (1) station a draws numbers: 0.31, 0.27, 0.78, 0.9, 0.9, 0.11, 0. (2) station b draws numbers: 0.45, 0.28, 0.11, 0.83, 0.37, 0.22, 0. (3)station c draws numbers: 0.1, 0.2, 0.3, 0.4, 0. (4) station d draws numbers: 0.36, 0.77, 0.9, 0.1, 0.1, 0.1, 0.1, 0. (b) in slotted aloha, a station transmits in each time slot with a given probability. what probabilities would you assign to each of the four stations so as to: (i) maximize the efficiency of the protocol? (ii) maximize fairness among the four stations? (c) will the efficiency increase or decrease if we modify slotted aloha as follows: (i) get rid of slots and allow stations to transmit immediately? (ii) implement carrier sensing? (iii) implement collision detection? (iv) implement collision avoidance?

Avariable of the data type arrays is storing 10 quantities. what is true about these quantities? a. the quantities all have different characteristics. b. the quantities all have the same characteristics. c. five quantities have the same and five have different characteristics. d. it is necessary for all quantities to be integers. e. it is necessary for all quantities to be characters.

22. sata3 allows for data transfer rates of 600 mb/s. explain why you would likely not be able to copy data from one hard drive to another at anywhere close to this speed. also, what could be upgraded on the computer to achieve transfer speeds closer to 600 mb/s