BIOS & Intro to Core Hardware & Firmware—CompTIA A+ (220-1001) A-PLUS Certification Prep Course Notes

Firmware

What is BIOS/UEFI?

BIOS programs are code.

Basic Input/Output Services

Note: Every motherboard in existence has built-in to it a small program designed to let us talk to the assumed hardware of the computer, and it’s called, ‘BIOS’.

• BIOS is a firmware, burned onto a chip, as opposed to software, which is copied onto some type of magnetic media or electronic media.
• BIOS programming enables interaction with the motherboard before the OS loads.
• BIOS is stored in non-volatile media, thus called firmware.
• POST (Power On Self Test) routines are built into firmware.
• The System Setup utility is also part of the firmware. (CMOS)

• POST—Power On Self Test
  • POST runs at boot, requesting devices to self check.
  • POST errors manifest as specific beep codes or display (text) codes.
  • POST cards enable testing of “dead” computers.

• System Setup
  • UEFI (Unified Extensible Firmware Interface)—“new improved BIOS!”

• UEFI replaces traditional 16-bit BIOS in modern systems
• The System Setup enables custom information about changeable devices.
• System Setup enables changes to CPU frequencies, RAM timings, BIOS passwords, boot options, and more.

• Troubleshooting Firmware
  • RTC (Real Time Clock)
  • CMOS battery
  • Flashing the ROM updates the firmware on the flashchip.
  • The real time clock battery keeps system time without external power.
  • System Setup allows for changes; exit without saving is an option.
  • Reset System Setup for defaults.
  • Flash the ROM chip to update firmware.

• Motherboards
  • Form Factor
    • 4 common form factors are: ATX, micro-ATX, mini-ITX and ITX.
  • Motherboards and cases follow standardized form factors.
  • Common form factors: ATX, microATX, MiniITX
  • Power supplies offer standardized connectors.
• Chipsets
  • Chipsets combine functions from many single-function chips.
  • Early chipsets offered Northbridge & Southbridge
  • Modern chipsets feature Southbridge (CPU handles Northbridge functions)
  • Chipsets define RAM capacity, USB capabilities, and much more.

• Touring the Motherboard
  • The motherboard manual provides essential setup information.
  • Motherboards come with cables, standard connectors, and more.
  • PCIe is the most common expansion bus, it offers multiple lanes.

• Touring the Case
  • Cases offer standardized standouts for mounting various motherboard form factors.
  • Better cases offer better cable management features.
  • Pick a case that has support for number and type of drives needed.

• Installing a Motherboard
  • Install and test CPU and RAM on motherboard before putting in the case.
  • Install I/O shield and triple check standard positions.
  • Mount motherboard and connect motherboard cables.
  • Use the motherboard manual if necessary.

Power Supplies

• Electricity Basics
  • Voltage = pressure; amount of flow = amperage;
    • V * A = Watts (work)
  • DC (Direct Current) = electrons move in the same direction;
  • AC (Alternating Current) = electrons move back and forth;
  • Use circuit tester ( or multimeter) to test AC from the wall outlet

• The Power Supply
  • Power supplies transform AC from wall outlet to DC for the computer
  • Standard connectors for motherboard are 20-24 pin ATX and 4-8 pin P4
  • Use Molex and SATA connectors for peripherals and drives
• Mounting a Power Supply
  • Mount power supply in case with four screws
  • Orient the power supply so fans draw air from system.
  • Connect motherboard primary & secondary power.
  • Modular PSUs offer less cable clutter than non-modular PSUs.

• Choosing a Power Supply
  • Get a PSU (Power Supply Unit) with a little more wattage than your system needs.
  • Shop for higher-effieciency power supplies
  • Modular power supplies cut down on cable clutter
• Power Protection
  • Electricity from the source is imperfect
  • Use surge protector/suppressor to protect against spikes.
  • Use UPS to protect against brownouts & blackouts. (Note: A surge protector is different from just a “power strip”.
    • Spikes and sags
    • 60 cycles/second = 60Hz
    • Sag = Short term voltage clip
    • Brownout = Intentional or unintentional drop in voltage.
    • Spikes = Provided more voltage than what you’re expecting; aka—“a surge!”
• UPS (Uninterruptible Power Supply)
  • protects from both sags/brownouts & spikes/surges.
  • has a battery back-up built in.
• Cooling Your PC
  • Overheat = Reboot
  • A heat sink draws heat from electrical components.
  • Fans blow heated air through and out of the system.
  • Fan speed & noise can be controlled through firmware or software.

• Troubleshooting Power Supplies
  • Power supplies die fast with burning smell, smoke, or both.
  • Power supplies die slowly & cause intermittent problems.
  • Use PSU tester or multimeter to test power supplies.

• Power Protection
  • Incorrectly installed CPUs or RAM can make it seem like your PC is dead.
  • Install core components and test before mounting into the case.
  • Errors in System Setup can cause a dead PC, try clearing the CMOS jumper.
  • Windows offers memory diagnostics tools to help with potentially bad RAM.