38 Computer Service and Repair
Multithreading
You may have heard the term thread or threads
used when referring to computer processing.
These terms refer to passing small portions of
a computer program through the core of the
processor. Data and parts of a program can be
shared between two or more CPUs or between
the two cores of a single CPU. This is called
multithreading instead of multitasking.
32-Bit and 64-Bit
Operating systems, hardware devices, and
software applications are identified using the
terms 32-bit and 64-bit. The terms 32-bit and 64-bit
are used to describe the amount of data that can
be stored or processed. For example, how much
data can be processed at once by the CPU or how
much total memory the operating system can
access.
The maximum amount of memory a 32-bit
Windows operating system can access is 4 GB.
Even if the computer contains more than 4 GB of
RAM, only 4 GB will be accessible by the 32-bit
operating system. A 64-bit Windows 7 operating
system recognizes a maximum of 8 GB or 128 GB
of memory depending on the operating system
edition.
Upgrading from one operating system to
another operating system or edition can be
affected by the number of bits it was written for.
For example, you can only directly upgrade a
32-bit operating system to another operating 32-bit
system or a 64-bit operating system to another
64-bit operating system. Upgrading directly from
a 32-bit operating system to a 64-bit operating
system would delete all data files (documents,
photos, music, etc.) stored on the computer. You
would have to back up all files, perform the
upgrade from 32-bit to 64-bit, and then reinstall
the data files and software applications.
User Interface
There are two dominant user interfaces
used to issue commands on a computer system:
command line interface and graphical user
interface. Graphical user interface is referred to
as GUI (pronounced gooey). The command line
interface is commonly referred to by Microsoft as
the command prompt.
Command Line Interface
The command line interface (CLI) allows
commands for the computer to be issued by
typing in text at a command prompt. Figure 2-2
shows a command line interface.
Some common commands are dir, cd, and
copy. These commands call up a directory, change
directories, and copy a file or disk, respectively.
See Figure 2-3 for a table of some common
commands. There are many more commands
than the few listed, but these are some of the most
commonly used.
DOS was the major operating system used
by PCs in the 1980s. However, DOS was difficult
to use. Users had to memorize many different
commands to become proficient with the
operating system.
Today, text-based commands are still used,
especially when troubleshooting. Text-based
commands are particularly important when a
PC fails to complete its startup process and take
the user to the GUI. Troubleshooting tools such
Figure 2-2.
Command line
interface.