BIOS...

[CLTEK]

I's wondrin' if'n y'all could answer me a question...

I'm new to this building computers stuff. So please pardon my ignorance. But I was wondering what the standard initial boot procedures are like.

You have your MB, your cpu, and say... Your RAM, and HD(s) in place. What happens when you turn the computer on for the first time? I mean, there's no OS yet, right? How does the BIOS (I'm guessing BIOS stands for something like Basic Instruction Operating System.) know what to do? How is it that a BIOS like the Award BIOS with Softmenu III recognizes the harware that you have plugged in? How does it 'know' that the CPU is a 'Genuine Intel Pentium xxx'? Is there some sort of recognition signal that the hrdwre sends out for the BIOS to read upon initialization? What?

I notice that on my POS Compaq, the first thing that comes up on the screen when I turn it on is a hrdwre detection thing that looks for my SCSI drive. Is that coming from my BIOS? I would assume so, since Win98 hasn't been loaded yet.

One more question if you would so entertain it... How can I get to the BIOS on myu Compaq to see what it looks like?

Uh... sorry for the sheer quantity of questions this time around.

Much Love and Respect... Cory

 

[Guest]

Holy cow Cory! I can give you a brief explanation and point you to some other sources.

Briefly, the BIOS (Basic Input/Output System) is usually a singe chip on your motherboard. This chip contains a set of specific software instructions that are written to recognize and interact with the various pieces of hardware on your system...chipset, memory, hardrives, etc. Your BIOS works in conjunction with your <b>chipset</b>, which is usually a sort of go-between between the BIOS and your specific hardware.

Each piece of hardware has its own information programmed into some onboard chip (and maybe its own BIOS). The motherboard BIOS ultimately reads this information. This is how it knows what you have.

When you first turn on your PC, the BIOS does a test called a <b>POST</b> (Power On Self Test). The POST checks for specific hardware like your memory, keyboard, hard drive, etc.

Then the BIOS looks for a boot device and a valid "master boot sector," then executes the boot sector code. This in turn loads your operating system.

There are also various config files (depending on your operating system) on your hard drive that may load various "device drivers" to help your operating system work with your hardware.

History (I haven't read about this in many years, so take it for what it's worth...may not toatally correct):

Earlier BIOSes (and presumably motherboard BIOSes) contained a set of chips called <b>PROM</b>s (Programmable Read Only Memory). Once you programmed the chip, there was no way to change it.

Later, someone invented the <b>EPROM</b> (Erasable Programmable Read Only Memory) chip. Each chip could be programmed, but as you might guess, you could erase it and reprogram it. Each chip had a little window in its top that was usually covered by a sticker. To erase it, you uncovered the sticker and put it under a device that shot UV rays into the chip for a certain amount of time, until everything was erased. Then you could reprogram it.

Since the average user didn't have the UV eraser and the device to reprogram the EPROM (often called a "burner"), you still needed to order a new BIOS when you had to change it.

In more recent years came the <b>EEPROM</b> (Electrically Erasable Programable Read Only Memory) chip, which enabled the invention of the "FLASH BIOS" we see in motherboards today. You can use a piece of software (called a FLASH utility) to change your motherboard BIOS while it's still in your PC. So when you upgrade a BIOS on a current motherboard, you need two files: The FLASH utility and the binary file that contains your new BIOS (or the changes to the old one).

Realize that you can still screw up your BIOS chip if you flash it incorrectly or if something goes wrong, like a power hit, that restarts your PC. Then you're stuck ordering a new BIOS chip...assuming you can get one.

Finally, you'll probably see people call the BIOS the CMOS (Complimentary Metal-Oxide Semiconductor) and use the terms interchangably. This is incorrect. The CMOS RAM is actually a small chunk of memory on your motherboard, the contents of which is stored by electricity provided by a small battery (also on the motherboard). When you change and/or save a setting in your BIOS, you are storing it in the CMOS. Similarly, when you power on your PC, the BIOS reads the CMOS RAM and gets your stored settings. The CMOS is also tied into a device called the RTC (Real Time Clock), which provides the DATE and TIME for the PC.

That's it in a nutshell. There's a site called Trish's Hardware Hell located at <A HREF="http://www.hardwarehell.com/" target="_new">http://www.hardwarehell.com/</A>. This is just a list of various "helpful" sites. I noticed there is a section entitled "BIOS and Motherboard," which points to some guides. I've not read any of them, but they may be worth the effort. I also know that there are a ton of other guides around on the Web.

There's an excellect reference book that's been around for God knows how many years called: <i>Upgrading and Repairing PCs</i>, by Scott Mueller. I think he's up to the 11th or 12th edition. This will tell you just about anything you want to know about your PC (and a lot you don't). It's not cheap and weighs in at around 1500 pages, but I highly recommend it to anyone wanting to learn more about PCs. (It really doesn't say that much about upgrading.)

I don't know how to access the Compaq's BIOS. On many motherboards you can hit the <DEL> or <INS> keys. On older Compaqs, you needed a setup disk.

Mike

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[CLTEK]

Holy Cow MIKE!!!

LOL! Thank you so much for the detailed reply. I will check out the links you have provided for me this evening whilst I'm here at the workplace.

Wow, man. Thanks a TON!

Much Love and Respect... Cory