OSDev.org

DavidCooper wrote:A much better route might be Micro-SD cards which are faster, have much higher capacity, and look as if they should give you the ability to switch cards just like floppy disks without having to worry about the drive number changing if you're accessing them through the BIOS [has anyone ever done this?]

Yes, that's what I do. I do not have support for floppy nor for cdrom, I use pendrives and SD cards (with USB case). Both can be used with BIOS 42h read without a problem.

turdus wrote:

DavidCooper wrote:A much better route might be Micro-SD cards which are faster, have much higher capacity, and look as if they should give you the ability to switch cards just like floppy disks without having to worry about the drive number changing if you're accessing them through the BIOS [has anyone ever done this?]

Yes, that's what I do. I do not have support for floppy nor for cdrom, I use pendrives and SD cards (with USB case). Both can be used with BIOS 42h read without a problem.

Thats because BIOS's that support booting for USB devices very kindly emulate them for you. The problem comes when you have to leave the BIOS behind, where you'll need a USB mass storage driver in order to read additional data from the drive\card. With CD's you'd need a much simpler ATAPI driver.

brain wrote:I am willing to change the tutorial to this however I may need some help on advising how to make iso images from commandline under windows (I have never used windows for osdev).

I prefer to work under windows and I know how to prepare bootable CD. Most easy way is to use mkisofs/cygwin. Within a week (I hope) I'll prepare the second version of my boot tools (set of first stage bootloaders with installer program) where it will be described in details. I'll post here as soon as it will be ready so you may borrow part of my readme and/or link there.

Instructions that would work on Linux and Cygwin are much preferred, if for no other reason than keeping the tutorial short.

it might make sense to split the barebones tutorial up some, so that after youve written a kernel you can pick a different sub-page for if you want to put it onto cd, a raw floppy, or just boot it directly in qemu (it is multiboot after all).
The CD page could have universal win/nix instructions.

berkus wrote:

brain wrote:it might make sense to split the barebones tutorial up some, so that after youve written a kernel you can pick a different sub-page for if you want to put it onto cd, a raw floppy, or just boot it directly in qemu (it is multiboot after all).
The CD page could have universal win/nix instructions.

Sounds good. You volunteered?

Yeah that's the idea lol

Rudster816 wrote:Thats because BIOS's that support booting for USB devices very kindly emulate them for you.

Yeah, that's what makes them ideal boot media. Nevertheless they're backward compatible with HDD (512 sector size, partitioning table and arbitrary filesystem support, writeable storage).

The problem comes when you have to leave the BIOS behind, where you'll need a USB mass storage driver in order to read additional data from the drive\card. With CD's you'd need a much simpler ATAPI driver.

That's not a problem, since any modern OS must have drivers for USB mass storage. And having a ramdisk (initrd loaded to RAM by BIOS calls) is an easy and cheap solution for the chicken-egg-problem until you finish proper USB/ATA/SATA/ATAPI support.

any modern OS must have drivers for USB mass storage

"must" is definitely wrong - not all OSes are for desktops...

Combuster wrote:"must" is definitely wrong - not all OSes are for desktops...

Please name a mainstream OS that's used in non-desktop environment and does not have USB support.
- embedded linux (such as Android, Maemo, MeeGo, OpenWRT, RouterOS, etc.): has.
- Cisco IOS: has.
- MacOSX iOS: has.
- JunOS: has.
- Symbian OS: has.
- Inferno: has.
- PalmOS: has.
- Windows Phone: has.
so...

turdus wrote:Please name a mainstream OS that's used in non-desktop environment and does not have USB support.

Although you may turn iOS device as mass storage, you cannot attach USB storage and access it within iOS, so I would say no for iOS.

bluemoon wrote:Although you may turn iOS device as mass storage, you cannot attach USB storage and access it within iOS, so I would say no for iOS.

Maybe it's not offical, but Mach kernel has drivers for it. So it is possible: http://www.youtube.com/watch?v=9qDrDC-HD-M

to have != must have...

osdev.org != mainstream...

As I promised, here are the instructions for preparing bootable CD under Windows.
http://goncharov.pp.ru/en/osboot.htm#cdrom