3. The computer loads data from read-only
memory (ROM) and performs a power-on
self-test (POST) to make sure all the major
components are functioning properly.
As part of this test, the memory controller
checks all of the memory addresses with a
quick read/write operation to ensure that
there are no errors in the memory chips.
Read/write means that data is written to a
bit and then read from that bit.
4. The computer loads the basic input/output
system (BIOS) from ROM.
The BIOS provides the most basic
information about storage devices, boot
sequence, security, Plug and Play (auto
device recognition) capability and a few
other items.
5. The computer loads the operating system
(OS) from the hard drive into the system's
RAM.
Generally, the critical parts of the operating
system are maintained in RAM as long as the
computer is on.
This allows the CPU to have immediate
access to the operating system, which
enhances the performance and functionality
of the overall system.
6. When you open an application, it is loaded
into RAM.
To conserve RAM usage, many applications
load only the essential parts of the program
initially and then load other pieces as
needed.
7. After an application is loaded, any files that
are opened for use in that application are
loaded into RAM.
8. When you save a file and close the
application, the file is written to the
specified storage device, and then it and the
application are purged from RAM.
9. -In the list above, every time something is loaded
or opened, it is placed into RAM.
This simply means that it has been put in the
computer's temporary storage area so that the
CPU can access that information more easily.
The CPU requests the data it needs from RAM,
processes it and writes new data back to RAM in a
continuous cycle. In most computers, this
shuffling of data between the CPU and RAM
happens millions of times every second.
When an application is closed, any accompanying
files are usually purged (deleted) from RAM to
make room for new data. If the changed files are
not saved to a permanent storage device before
being purged, they are lost.
10. In this way a computer starts and
performs its jobs in a continuous cyclic
process, every time in RAM something is
loaded and it is purged from it after the
application gets closed.