CIS 1110A - Computer Operating Systems and Maintenance

Module 2

This lesson presents some background motherboards. Objectives important to this lesson:

  1. Types of motherboards
  2. BIOS or UEFI
  3. Drivers and firmware updates
  4. Replacing a motherboard
  5. Current assignments


The chapter begins with an illustration of an ATX motherboard. A what? If a processor is a computer's brain, the motherboard is the body that communicates with the brain. Motherboards come in several types and each can have a number of features that allow the connection of and to other components of the computer. This takes us to a new term. A form factor is defined as a size, shape, and set of features. The author observes that, when building a computer, you should pick a form factor for the motherboard first, which will limit or determine your choices for cases, processors, types of memory and expansion cards, and power supplies.

The author could have introduced you to any number of historical motherboards. She tells us about three that are addressed on the current A+ tests:

  • ATX - the author says these can be up to 12 by 9.6 inches
  • microATX - also called mATX; a smaller board than the ATX, made to fit smaller cases; typically it has fewer slots: note the three white PCI slots on the mATX and the four yellow slots on the ATX in the image below; microATX motherboards are 9.6 by 9.6 inches
  • miniITX - a small form factor (SFF) board for small, low power devices that provide specific functions; miniITX motherboards are 6.7 by 6.7 inches

There are other form factors. The image below shows the relative sizes of five motherboards made by the Lanner company. There is also a pen in the image to give you an ideal of relative size. Note that the Lanner site says their ATX motherboard is 12 x 13 inches, which is not possible if the image below is accurate. Trust the author of our book on sizes.

The author remarks that smaller boards may fit larger cases, which is discussed in the video below.

Search online for other images of motherboard form factors to get an idea about more types.

The next topics are chipsets and processor sockets, both of which are motherboard features. A chipset (a set of chips on the motherboard) provides interfaces between a processor and a computer's memory, expansion slots, and other peripherals. As you may imagine, there are chipsets for each generation of Intel processors and other for each generation of AMD processors. (Yes, there are other brands, but those are the big two for computers.)

Each generation of processors typically has an associated socket type, which in turn will have one or more associated chipsets. The socket type determines which processors will fit the motherboard. Let's let Linus Sebastian talk about it. (Ignore the commercial in the video. It was shot in 2016.)

So, if you watched the show, you learned that...

  • Intel sockets have pins and Intel processors have lands (flat areas where the pins touch the processor)
  • AMD processors have pins, and AMD sockets have arrays of sockets those pins fit into
  • Processors, chipsets, and processor sockets must all match, or the computer won't work (or will die when you turn on the power)

The text discusses expansion slots on motherboards, telling you that you only need to know about PCI slots and those that followed them. The video below discusses PCI and earlier technologies as well. I believe it is better to know something about where we came from if you want to understand where we are and where we might go next. And the presenter has a British accent, which always sounds more intelligent to American audiences.

This explains the notation on page 76: A PCIe x 1 slot allows one lane of data. A PCIe x 16 slot allows 16 lanes of data at the same time. Much wider data bandwidth.  Plugging an x16 card into an x4 slot may still work, but it ruins the intended processing power of the card. Speaking of power, the actual electrical power required by a card may have to come from the motherboard slot and from an additional connector. Page 77 shows us images of an 8 pin Molex connector on a card, a 4 pin Molex connector on a motherboard, and a SATA connector on a motherboard. Warning: the next image could be dangerous to your PC!

Well, this one is actually okay, depending on what you do with it. In the image above, you see a SATA male connector at the upper right which branches to a 4 pin Molex female connector and a SATA female connector. The danger of what was meant to be a useful adapter is explained on this page at Crucial, a maker of connectors and memory. Applying power from a Molex source to an SSD SATA connection could lead to a fire in the computer. Don't do that. First rule of fire safety: don't let the fire start.

The text briefly mentions riser cards. Sometimes, a small motherboard may have only one expansion slot. If so, you need to install a riser card in it if you intend to install expansion cards.

PCI riser card

In the image above, you see a riser card that plugs into a PCI slot. It allows the installation of up to three PCI expansion cards, assuming that they are thin enough and short enough to fit in the riser card and in your case. In this instance, your single slot on the motherboard becomes a shared bus for any cards you insert into the riser card.

USB A and B If you have used computers at all, you have probably seen arrays of ports like the one shown on page 79. The PS/2 port shown at the image's upper left may seem unfamiliar. It was commonly used to attach either a mouse or a keyboard to the computer before USB A ports became a standard. For reference, the image on the right shows a cable with a USB A connector on the left and a USB B connector (typically used for printers) on the right.

The text goes on to discuss three data ports that have already been mentioned, an old one that has not:

  • SATA - Serial ATA ports are commonly used to connect the motherboard to storage devices such as hard drives and optical drives
  • M.2 - This is a newer standard commonly used to attach Solid State Devices (SSDs) or wireless cards to motherboards; when choosing a card for your motherboard, examine the slot you are about to use, and determine if it is style B (notch/post on the left) or style M (notch/post on the right)
  • IDE - this was a standard for years for connecting hard drives to motherboards; see the socket and black connector (at the end of a ribbon cable) shown on page 82
  • USB - in this case, you are instructed to note the motherboard connection types for a USB bus: USB headers have pins and may be cryptically labeled; see the video below for a good demonstration

The text continues with software that is stored on the motherboard itself. Two types are mentioned:

  • BIOS - found on computers built before 2012
  • BIOS/UEFI - found on computers built after 2012

The discussion about the transition from BIOS (Basic Input-Output System) chips to UEFI (Unified Extensible Firmware Interface) is a little light. This article on is a bit more readable and detailed. Short version: UEFI supports more memory and larger storage devices at boot time. BIOS chips could only operate in 16-bit mode, so modern processors have to gear down to use them, at least until the main operating system is loaded. For an explanation in a video, take a look at this one:

The video discusses the memory and storage device issues, but it goes to a commercial at about 3:55, which we can skip. UEFI supports Secure Boot which is meant to protect your computer from having its operating system compromised. The system starts by verifying hardware, then verifying each layer of software in a chain of trust. Like most features, you can turn Secure Boot off, which you would want to do if you need your computer to be able to boot into multiple operating systems.

You can use either system to set security functions, change the boot order of your drives, and tell the system about new devices you've added to the computer. Note the short sections about encryption, TPM chips, and enabling UEFI to support virtual machines: A+ cares about these concepts.

Updating drivers is not challenging. You typically download a new driver from either your computer manufacturer's web site, or from the site of the maker of the hardware in question. Download, click to install, and follow the prompts.

It is sometimes necessary to do an unusual thing with the motherboard. Page 97 in the text shows a set of six jumper pins that can be used to modify a computer's startup. Jumper pins are open circuits until you bridge two of them with a jumper cover (also called a jumper). The text gives an example of a row of three pins.

  • Covering pins 1 and 2 tells the motherboard to boot normally.
  • Covering pins 2 and 3 instead tells the motherboard to present a screen to remove a power-on password.
  • Covering no pins (which would be the same as covering only one pin) tells the motherboard to go into a BIOS recovery (reset).



  1. Read the chapter, and the next one for next week.
  2. Complete the assignments and class discussion made in this module, which are due by 6pm next week.