BIOS and UEFI - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer
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Quite a bit of info in a short amount of time. How do you reset the BIOS if it loads off a flash then?
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@mary said in BIOS and UEFI - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:
Quite a bit of info in a short amount of time. How do you reset the BIOS if it loads off a flash then?
The settings are normally on writeable media, that is just super tiny.
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I can't believe I never knew what BIOS was before this haha. Would BIOS have also been used in the early days of computers? Or is it only necessary because of operating systems.
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@mary said in BIOS and UEFI - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:
Quite a bit of info in a short amount of time. How do you reset the BIOS if it loads off a flash then?
You will usually reset the BIOS settings with a jumper on the motherboard. You can also restore the settings to the default settings - if you can enter the BIOS setup. But if it's password protected you can't.
The BIOS itself resides in flash memory nowadays and it can be reprogrammed - if you can boot your computer.
Servers usually have a different computer onboard as well for remote management, a BMC. That's what runs remote management software like ilo, idrac and ipmi. Often you can reprogram the BIOS from the BMC as well.
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@connorsoliver said in BIOS and UEFI - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:
I can't believe I never knew what BIOS was before this haha. Would BIOS have also been used in the early days of computers? Or is it only necessary because of operating systems.
Operating system is just software. The BIOS is a bootloader which basically means that it is where the CPU starts executing code when it's powered on.
In the dawn of PCs (late 1980s) the BIOS was an EPROM. That's an erasable programmable read-only memory. Can't be changed unless you erased it first. Had to reprogrammed with a device and you had to remove the chip from the motherboard to do it.
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@connorsoliver said in BIOS and UEFI - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:
I can't believe I never knew what BIOS was before this haha. Would BIOS have also been used in the early days of computers? Or is it only necessary because of operating systems.
A BIOS has always been there. Without it, you can't really load anything. It didn't always have the name BIOS, but there always had to be something to allow the system to load a program.
In the earliest days, the BIOS was "input by hand" using switches! But that didn't last long.
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@Pete-S How long did you spend holding UV lights over those chips? Me = many hours, way to long.
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The name BIOS is what IBM called it's boot ROM.
BIOS had most of the hardware drivers that you needed to run the computer. It had code for reading from disks, managing the keyboard etc. That's why the BIOS has to know about what disks are in the system so it knows how to proceed with the boot sequence. It's the BIOS that goes looking for the MBR (master boot record) on the drives and then loads that into memory and reads and executes the code it points to.
It's also the BIOS that goes looking for other ROMs during boot, for instance boot ROM on the network cards, video ROM etc.
Early programming in DOS means you had to interacted with the BIOS.
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@travisdh1 said in BIOS and UEFI - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:
@Pete-S How long did you spend holding UV lights over those chips? Me = many hours, way to long.
Haha, spent a lot of time doing that. But I had an UV eraser which basically meant you could put it in and walk away.
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@Pete-S said in BIOS and UEFI - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:
@travisdh1 said in BIOS and UEFI - CompTIA A+ 220-901 220-902 Video Training by Prof. Messer:
@Pete-S How long did you spend holding UV lights over those chips? Me = many hours, way to long.
Haha, spent a lot of time doing that. But I had an UV eraser which basically meant you could put it in and walk away.
I spend enough time doing it so I could immediately tell that the EPROM I posted a pic of above, is made by Texas Instruments (from the logo) and it's 256 kbit (from 27C256) so 32 kilobyte memory.
