1.5.2 Timer. 1  Before the kernel begins executing user code, a timer is set to generate an interrupt. 2  The timer interrupt handler reverts control back to the kernel. 3  This assures that no user process can take over the system.  Timer control is a privileged instruction, ( requiring kernel mode.
The Liberty Bell was cast in the Whitechapel Foundry in London and hung in the belfry of the Pennsylvania State House in 1753. That building is known today as Independence Hall. The bell cracked upon its first use before being recast twice by John Pass and John Stow, of Philadelphia. You can see their names inscribed on the bell as well as a Biblical verse from Leviticus, Proclaim Liberty throughout all the Land unto all the Inhabitants thereof..
To many people the Liberty Bell represents different things. It represents freedom, history, and our rights as Americans. For me, the Bell provides the sense of strength. Our Founding Fathers signed the Declaration of Independence, an enduring symbol of our freedom.he Liberty Bell symbolizes and means to me, Freedom, Love and Peace and for others. My country, United States America has it more than any country in the world. I am proud of the Liberty Bell and the United States of America.