The memory of a particular microcomputer is built from 64K * 1 DRAMs. According to the data sheet, the cell array of the DRAM is organized into 256 rows. Each row must be refreshed at least once every 4 ms. Suppose we refresh the memory on a strictly periodic basis. a. What is the time period between successive refresh requests? b. How long a refresh address counter do we need?

Consider this data sequence: "3 11 5 5 5 2 4 6 6 7 3 -8". any value that is the same as the immediately preceding value is considered a consecutive duplicate. in this example, there are three such consecutive duplicates: the 2nd and 3rd 5s and the second 6. note that the last 3 is not a consecutive duplicate because it was preceded by a 7. write some code that uses a loop to read such a sequence of non-negative integers , terminated by a negative number. when the code finishes executing, the number of consecutive duplicates encountered is printed. in this case, 3 would be printed. assume the availability of a variable, stdin, that references a scanner object associated with standard input. that is, stdin = new scanner(system.in); is given.

Usually, when we sniff packets, we are only interested certain types of packets. we can do that by setting filters in sniffing. scapy’s filter use the bpf (berkeley packet filter) syntax; you can find the bpf manual from the internet. set the following filters and demonstrate your sniffer program again (each filter should be set separately): (a) capture only the icmp packet. (b) capture any tcp packet that comes from a particular ip and with a destination port number 23. (c) capture packets comes from or to go to a particular subnet. you can pick any subnet, such as 128.230.0.0/16; you should not pick the subnet that your vm is attached to.

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