Computer Technicians 202: BIOS Functions and Firmware Flashing

Last time, in the TNCT 201 article, we discussed a strategic approach to expanding your market. Regardless of whether you’re dealing with home repairs, SoHos or even your own computer, sooner or later you’ll have to fiddle with the lowest-level functions, either to fix or optimize something. Today we’ll discuss the nature of BIOS, its general functions – which vary between manufacturers and models – some common chokepoints, and finally, ways of upgrading or fixing it. Learning to use and upgrade your BIOS and other flash firmware is primarily for optimization purposes, but can come handy in overcoming some very basic hardware problems.

Life in a silicon box

The BIOS – or Basic Input-Output System – is the lowest level of hardware-software interfacing a regular user can access. While it commonly refers only to the software side of it (the so-called system setup), in this course we’ll use the term to describe both the software and the hardware it’s stored in.

Looking from a hardware perspective, the BIOS is a small integrated circuit usually located near one of the corners of the motherboard. The BIOS is usually stored inside a PROM, EEPROM or flash ROM. The key difference between the three possible ROM types is their age and programmability. PROMs (Programmable Read-Only Memories) are the oldest type which was designed to be programmed once and once-only, similar to a CD-ROM, and are usually only encountered on very old PCs (predating 1990). EEPROMs (Electrically Erasable PROMs) are the “medium” type designed as reprogrammable, but still aren’t too common on today’s machines. Flash ROMs have been a de facto standard for a long while now, and, naturally, they inherit the reprogrammability EEPROMs have. BIOS ROMs are accompanied by a smaller CMOS memory circuit which stores the BIOS settings, while some motherboards may also have a second BIOS ROM chip – more on this later.
Looking on it as a software piece, the BIOS contains the basic instructions that allow the computer to function as a whole by preparing the various components, first by running a POST sequence (power-on self-test), and later providing the full OS with means to handle components. In the past, the BIOS functioned as the sole interface through which all components communicated. While it’s no longer true, the BIOS still handles important instructions and allows the user to customize the settings in order to get the maximum performance or stability out of the system.

Messing with the settings

While BIOS does indeed stand for Basic Input-Output System, it’s interesting to note it’s pronounced the same way as the greek word for life – something it’s definitely suited for, as it decides how the machine will act once power is switched on. Although there are several prominent BIOS manufacturers and programmers, such as American Megatrends, Phoenix Technologies and Award International, most of the BIOS interfaces are organized similarly, nevermind the graphical layout. Accessing the BIOS usually involves hitting the DEL, F2 or any other function key during boot-up sequence – this varies depending on the exact motherboard. Some of the more common sections of the average Award BIOS, for instance, are:

  • Standard BIOS settings – these usually contain the system time and date setup, as well as the basic IDE or SATA drive settings. The latter are usually set to AUTO so the system would autodetect the connected disks or DVD-ROMs on boot.
  • Advanced BIOS settings – these contain settings such as hard-drive boot priority, general boot device priority (for kickstarting brand new machines), as well as RAM latency settings on better motherboards.
  • Integrated peripherals – these allow you to change the funcionality of various integrated element such as onboard sound, network connectors, parallel and serial ports and the like.
  • Power management – this section sets how the machine will power up and shut down, i.e. whether pressing the power button will instantly shut the machine down, or if you’ll have to keep it pressed for 4 seconds. This section also covers more advanced options such as Wake-on-Ring or Wake-on-LAN.
  • PC Health – a relative newcomer to BIOS screens, this one is useful if you want to check on voltages and temperatures, and also lets you set the alarm if the CPU temperature exceeds a certain level.

All in all, the available settings will vary wildly depending on the actual motherboard, since different ones have different features, naturally.

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Comments (2)

  • Gary says:

    Bios upgrades should only be performed as a last resort to fix a known problem or a updated cpu. Always backup your existing bios and make sure you only perform this procedure at DOS level and only ever have one CD/DVD rom connected if using PATA drive to flash the bios. It is also very common for the bios software to become corrupted and be responsible for a unstable system. I had a problem with a “Windows Protection Error” on a Windows 98 machine, the Ram tested OK in another machine, so as a last resort I reflashed the motherboard bios and fixed the problem.

  • ANDREW says:

    im being incriminated