The BIOS calls used to detect installed memory are not availible from protected mode. The CMOS is unreliable, and cannot report the amount of installed memory above 99M. Probing is also unreliable, particularly in instances where two memory banks are separated as far as physical addresses are concerned.

For more information, see http://www.mega-tokyo.com/osfaq2/index.php/How%20do%20I%20determine%20the%20amount%20of%20RAM%3F - it explains why most methods other than BIOS are unreliable or unuseful.

Yes, most all are true, but...you can use PnP BIOS and SMBIOS both in protected mode to determine the mount of ram installed. SMBIOS will give you the amount per stick of installed RAM. PnP BIOS will give you the detailed information that INT 15h E820 will give you, and more, since it does tell you which ROMs are installed and where.

As for probing, if your algorythm is sufficient you WILL find all RAM installed.

In my OS I use CMOS, Int 15h AH=88h, INT 15h AX=E801h, INT 15h AX=E820h, PnP BIOS, SMBIOS, and finally probing. I also use PCI BIOS 32 to determine where PCI devices put their respective memory areas.

There are two more areas I need to research before I am satisfied with my findings for memory determination: ACPI and ESCD table.

While my OS doesn't display Boch's as having PnPBIOS or SMBIOS, it does recognize INT 15h AX=E820 and saves the corresponding table for review. With PnP, the two are combined and show an aweful lot of information about your system. http://smiddyOS.asmhackers.net/pictures/smiddyOS-Display.bmp

Enjoy!

Yeah, really good Smiddy. I wish I could convince you to stop fooling around with Bochs and floppies, and switch to a solid partition on a hard drive using Ranish and XOSL, for example. Your information displayed during bootup is just outstanding.

Thanks for the kudos. I am in transition right now, but your point is well taken. I have set aside enough space for a small FAT32 partition (or other) and will consider making that available for my upcoming demo. This may take some time however, since I'm moving across country, so I will be looking for a house next week, then living in temporary housing until I find a place. I'll keep you informed though.

I'll have to look at both of those, since I haven't as yet.

Are there any bootloaders that follow the Multiboot Specification?

grub... lol

http://www.ranish.com/part/

I found an example (bootphp). I have tried to compile it and it soesn't work (Invalid operand or something). What is going on? (FASM examples from http://flatassembler.net/examples/phboot.zip)