A+ Certification

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Navigation[edit]

Disassembling and reassembling a computer[edit]

One of the best things you can do to prepare for the exam is to learn the function of and how to identify the hardware inside of a computer. The following is a rough guideline for the order in which to disconnect components from your computer system. Be sure to place items in anti-static bags, where appropriate. Static electricity can damage components or destroy data. Always wear an anti-static wrist strap when working inside the case. DO NOT wear one while the power is still attached.

  1. Detach external devices
    1. Detach power cable
    2. Detach keyboard and mouse
    3. Detach monitor
    4. Detach serial, parallel, and USB devices
    5. Detach network cables, telephone lines, speaker cables, etc.
    6. Detach all other peripheral devices
    7. Remove system case
  2. Remove internal components (be sure that the computer is unplugged from any power source before removing components) (but, remember that if you unplug the power, the computer components are no longer grounded and there is increased likelihood of device damage from electrostatic discharge. This is why you should wear an anti-static wrist strap.)
    1. Detach internal power cables and connectors from all storage devices
    2. Remove hard drive, floppy drive, CD-ROM and other storage devices
    3. Remove interface cards
    4. Remove power cables from system board
    5. Remove all other cables from the system board
    6. Remove screws or clips holding motherboard in place
    7. Remove motherboard
    8. Remove DIMM or RIMM memory modules
    9. Remove CPU fan, heat sink, and CPU


Consider grounding yourself by touching the power supply before unplugging the power cable. And after you unplug it, hold the power button for 5 seconds, to discharge the computer (i.e. until the LED on the mother board dies). You must still use your anti-static wrist strap, however.

The computer should be reassembled in the reverse order. For the exam one must know how to install and configure hardware and other input and multimedia devices. There is no practical component to any of the A+ exams.

Identifying hardware components[edit]

One of the essential requirements for A+ Certification is identifying names, purposes, and characteristics of specific hardware components, including the following:

These are not devices:

Identifying operating systems[edit]

Although the examination focuses almost exclusively on Microsoft's Windows operating system (OS), one should also know about differences among other operating systems.

Microsoft operating systems:

  • Legacy Windows OSes (need only to know upgrade paths):
    • Windows 95
    • Windows 98
    • Windows ME
    • Windows NT 4.0
    • Windows 2000
    • Windows XP
  • Current Windows OSes (focus on these for the new exam):
    • Windows Vista
    • Windows 7
    • Windows 8
    • Windows 10

Apple operating systems:

  • Mac OS X (which is based on Unix-like system-exam question)
  • iOS (for iPhone, iPad, iPod Touch)

Unix-like operating systems:

  • BSD (and derivations like FreeBSD, OpenBSD, and NetBSD)
  • NextStep
  • GNU/Linux
  • Google Android

Boot Process for Operating Systems[edit]

DOS BOOT PROCESS[edit]

  1. Upon powering on the machine a POST (Power on Self Test) is executed, this does a quick test on things such as the memory and power supply of a machine. POST transfers control to CMOS (Complementary Metal Oxide Semiconductor) which contains the BIOS (Basic Input Output System). The BIOS loads various low level settings such as boot-order and network settings. The BIOS is also a very useful tool for testing memory or hard drives, as well as finding out basic information such as serial numbers and asset tags. Note if POST fails it is usually identified by various light or audible beep codes which often can be searched for by model on the manufacturers' website.
  2. The BIOS searches attached disk drives and peripherals (such as USB flash drives) for a valid Master Boot Record (MBR). The MBR contains a series of tasks for loading an Operating System (OS). If a valid MBR is found, instructions for loading the OS are read. If no valid MBRs are detected by the BIOS, an error message is displayed.
  3. Instructions from the MBR are read. These instructions check the floppy, CD-ROM, or hard drive (not necessarily in that order). The MBR points to the boot sector, which locates IO.SYS and loads the file into RAM.
  4. IO.SYS is a file that loads low level drivers for hardware devices like the keyboard, serial and parallel ports, floppy drive, and hard drive. Next, IO.SYS will run Sysinit which in turn loads Msdos.sys into RAM.
  5. MSDOS.SYS in turn helps manage the input and output for the hard disk. It processes the commands in Config.sys. Config.sys loads all the other device drivers and manages memory for optimization.
  6. Command.com is loaded into RAM. Command.com is a file that stores all your internal commands.
  7. Command.com then processes Autoexec.bat which will set the initial configuration of DOS. The user can add what programs to start each time the computer boots.
  8. The last step will get you the command prompt.

WIN95/98/ME BOOT PROCESS (Similar to DOS)[edit]

  1. POST is performed.
  2. Master Boot Record (MBR) is loaded into RAM and locates the boot sector. The boot sector then locates the Io.sys.
  3. The Io.sys runs Sysinit and loads Msdos.sys into RAM.
  4. Io.sys then loads System.dat, but does not process at this time.
  5. Io.sys then loads Config.sys and Autoexec.bat. These are not necessary to load the operating system, but are needed when 16 bit (real mode) drivers are used.
  6. Io.sys then loads Win.com which start the operating system.
  7. Win.com loads drivers specified by the registry.
  8. Win.com processes the System.ini and Win.ini files. System.ini is used to configure the memory cache and buffers. Win.ini is used for 16-bit applications. Otherwise, they are run by the registry.
  9. Win.com will start KERNEL32.DLL, KERNEL386.EXE, GDI.EXE, and GDI32.EXE. The Kernel files are the operating systems. The GDI files are responsible for the graphical functions and display.
  10. The Kernel files will load the Explorer user interface, which includes the Desktop, Taskbar, and Start Menu.
  11. The Kernel will then process anything in the Startup folder and restore network connections.
  12. The user can now interact with the operating system.


WIN2000/NT/XP BOOT PROCESS[edit]

  1. BIOS runs POST.
  2. Computer finds the boot device and loads Master Boot Record (MBR) into RAM.
  3. MBR looks for the active partition on the boot device and loads the boot sector.
  4. The boot sector in turn starts the Ntldr file which will load the operating system.
  5. Ntldr configures the computer’s processor to recognize all of the memory.
  6. Ntldr will start the file system, and the operating system will load, whether it is FAT or NTFS.
  7. Ntldr checks the Boot.ini file to find the operating system(s) and to create the boot menu.
  8. After the operating system is selected, Ntldr will run Ntdetect.com which will make the hardware list.
  9. Ntldr will load Ntoskrnl.exe which is the kernel of the operating system.
  10. The operating system will start the graphical interface.
  11. Ntoskrnl.exe loads Smss.exe which is the Session Manager.
  12. The user logs on.

WINDOWS VISTA / 7 BOOT PROCESS[edit]

  1. BIOS runs POST.
  2. Computer finds the boot device and loads Master Boot Record (MBR) into RAM.
  3. MBR looks for the active partition on the boot device and loads the boot sector.
  4. The boot sector in turn starts the bootmgr file, which loads the operating system.
  5. bootmgr configures the computer’s processor to recognize all of the memory.
  6. bootmgr starts the file system and the operating system loads. Windows Vista/7 must be NTFS.
  7. bootmgr checks the BCD and bootsect.bak files to find the operating system(s) and to create the boot menu.
  8. After the operating system is selected, bootmgr makes the hardware list.
  9. bootmgr loads Ntoskrnl.exe, which is the kernel of the operating system.
  10. The operating system starts the graphical user interface.
  11. Ntoskrnl.exe loads Smss.exe, which is the Session Manager.
  12. The user logs on.

See also[edit]