flat assembler
Message board for the users of flat assembler.

Index > OS Construction > Bootloader

Goto page Previous  1, 2, 3, 4
Author
Thread Post new topic Reply to topic
THEWizardGenius



Joined: 14 Jan 2005
Posts: 382
Location: California, USA
THEWizardGenius
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.
Post 28 Aug 2005, 23:09
View user's profile Send private message AIM Address Reply with quote
smiddy



Joined: 31 Oct 2004
Posts: 559
smiddy
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!
Post 29 Aug 2005, 00:25
View user's profile Send private message Reply with quote
tom tobias



Joined: 09 Sep 2003
Posts: 1320
Location: usa
tom tobias
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. Smile
Post 29 Aug 2005, 13:52
View user's profile Send private message Reply with quote
smiddy



Joined: 31 Oct 2004
Posts: 559
smiddy
tom tobias wrote:
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. Smile


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.
Post 29 Aug 2005, 17:13
View user's profile Send private message Reply with quote
Imagist



Joined: 13 Jun 2004
Posts: 114
Location: Pennsylvania (USA)
Imagist
Are there any bootloaders that follow the Multiboot Specification?
Post 01 Sep 2005, 18:57
View user's profile Send private message Visit poster's website Reply with quote
UCM



Joined: 25 Feb 2005
Posts: 285
Location: Canada
UCM
grub... lol
Post 01 Sep 2005, 21:24
View user's profile Send private message Reply with quote
tom tobias



Joined: 09 Sep 2003
Posts: 1320
Location: usa
tom tobias
Imagist wrote:
Are there any bootloaders that follow the Multiboot Specification?

http://www.ranish.com/part/
Smile
Post 01 Sep 2005, 21:50
View user's profile Send private message Reply with quote
Adam Kachwalla



Joined: 01 Apr 2006
Posts: 150
Adam Kachwalla
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)
Post 18 Jun 2006, 00:06
View user's profile Send private message Reply with quote
Display posts from previous:
Post new topic Reply to topic

Jump to:  
Goto page Previous  1, 2, 3, 4

< Last Thread | Next Thread >
Forum Rules:
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum


Copyright © 1999-2020, Tomasz Grysztar. Also on YouTube, Twitter.

Website powered by rwasa.