Answer:
The green-blue circuit board you can see in the first photo includes the disk controller, a circuit that allows the computer to operate the drive's mechanisms and read/write data to and from it. ... A small hard drive typically has only one platter, but each side of it has a magnetic coating
Explanation:
The answer is a) It improves upon the two-phased commit by requiring that locks be acquired at the start of a transaction.
Reason: The 3PC is an extension or you can say developed from 2PC that avoids blocking of an operation. It just ensures that first n sites have intended to commit a transaction that means it acquires commits or locks before the start of any transaction to avoid any blocking.
Option b) is wrong as it does not allow coordination, it just let all the other sites do their transaction if any other site is blocked, so no coordination is there between sites that they will wait till their coordinator is corrected.
Option c) is wrong as lock operations are shared between other connections as when their coordinator fails, the new coordinator agrees to the old coordinator that they had shared locks before and they can start their transaction.
Option d) is wrong as option a) is correct.
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Answer:
class studentType: public personType
{
public:
virtual void print() = 0;
virtual void calculateGPA() = 0;
void setID(long id) {
studentId = id;
}
void setCourses(const string c[], int noOfC) {
noOfCourses = noOfC;
for (int i=0; i<noOfCourses; i++) {
courses[i] = c[i];
}
}
void setGrades(const char cG[], int noOfC) {
noOfCourses = noOfC;
for (int i=0; i<noOfCourses; i++) {
coursesGrade[i] = cG[i];
}
}
long getID() {
return studentId;
}
string* getCourses() {
return courses;
}
char* getGrades() {
return coursesGrade;
}
studentType(string fName = "", string lastName = "",
long id = 0, string c[] = NULL, char cG[] = NULL, int noOfC = 0);
private:
long studentId;
string courses[6];
char coursesGrade[6];
int noOfCourses;
};
Explanation:
Code rewritten
Answer:
usable capacity = 10 GB
Number of cylinders = 256
Block size = 4 KB
(1)Bytes in each cylinder = (10*230)/(256) = (10*222) = 40 MegaBytes
(2)Number of Blocks in each cylinder = (10*222)/(212) = 10K
(3)capacity of one track = 40 MegaBytes/(10*2) = 2 MB
Rotation speed = 3840 RPM
Number of rotations per second = 3840/60 = 64
Transfer rate = (2*64) = 128 MB/sec
Explanation:
Hard drive failures
Accidental deletions
Computer viruses and malware infections
Power failures
