15.01.2024 Views

CompTIA A+ Certification All-in-One Exam Guide

  • No tags were found...

Create successful ePaper yourself

Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.

architecture. The Intel Core 2 Duo, for example, could run a program written

for an ancient 80386 processor that was in fashion in the early 1990s.

x64 When the 64-bit CPUs went mainstream, marketing folks needed some

way to mark applications, operating systems, and so on such that consumers

could quickly tell the difference between something compatible with their

system or something not compatible. Since you generally cannot return

software after you open it, this is a big deal. The marketing folks went with

x64, and that created a mess.

x86-64 The earlier 32-bit stuff had been marketed as x86, not x32, so now

we have x86 (old, 32-bit stuff) versus x64 (new, 64-bit stuff). It’s not pretty,

but do you get the difference? To make matters even worse, however, x64

processors quite happily handle x86 code and are, by definition, x86

processors too! It’s common to marry the two terms and describe current 64-

bit CPUs as x86-64 processors.

Virtualization Support

Intel and AMD have built in support for running more than one operating

system at a time, a process called virtualization. Virtualization is very cool

and gets its own chapter later in the book (Chapter 22), so I’ll skip the details

here. The key issue from a CPU standpoint is that virtualization used to work

entirely through software. Programmers had to write a ton of code to enable a

CPU—that was designed to run one OS at a time—to run more than one OS

at the same time. Think about the issues involved. How does the memory get

allocated, for example, or how does the CPU know which OS to update when

you type something or click an icon? With hardware-based virtualization

support, CPUs took a lot of the burden off the programmers and made

virtualization a whole lot easier.

EXAM TIP The CompTIA A+ 1001 objectives refer to virtualization

support as the virtual technology CPU feature.

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!