Floppy Partionning system

All discussions related to the DCPU and in game hardware (equipment, vehicles)

Re: Floppy Partionning system

Postby Cryptix » Thu Nov 07, 2013 4:08 am

I had the oddest feeling that no one would understand me and for some reason I was right, I don't know how.
I am under the assumption that you are talking about loading a BIOS program from a disk drive made up of multiple 512 word sectors of data, and that the computer was to load only the first sector under the assumption that a programmer put a bootloader there and that you said 512 words was to limiting for a bootloader as a bootloader that size could only load so many sectors of BIOS code. I said that if somehow the BIOS being loaded by the bootloader was to big (which would be retarded) for the 512 word bootloader to load then I said make the bootloader load a bigger bootloader big enough to load the full BIOS. Sorry if I misunderstood something here.
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Re: Floppy Partionning system

Postby Zardoz » Thu Nov 07, 2013 6:23 am

The BIOS isn't load from disk, as the BIOS is in a ROM. the only thing loaded from the disk is a bootloader or a bootable program. The bootloader can load many data as free RAM space.
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Re: Floppy Partionning system

Postby VladVP » Thu Nov 07, 2013 7:56 am

Cryptix wrote:I had the oddest feeling that no one would understand me and for some reason I was right, I don't know how.
I am under the assumption that you are talking about loading a BIOS program from a disk drive made up of multiple 512 word sectors of data, and that the computer was to load only the first sector under the assumption that a programmer put a bootloader there and that you said 512 words was to limiting for a bootloader as a bootloader that size could only load so many sectors of BIOS code. I said that if somehow the BIOS being loaded by the bootloader was to big (which would be retarded) for the 512 word bootloader to load then I said make the bootloader load a bigger bootloader big enough to load the full BIOS. Sorry if I misunderstood something here.
If you still cannot understand me then forget about it.

The BIOS is inside the ROM.
It's the first thing executed whenever a machine starts up.
It loads the first sector of an external storage unit into RAM.
Then it switches CPU execution over to RAM.
That first sector contains the boot loader.
The boot loader loads everything else needed by the programmer from an external storage unit.
The BIOS should only ever be executed once in a session.
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Re: Floppy Partionning system

Postby lamogui » Thu Nov 07, 2013 7:38 pm

The goal is to boat a REAL PRogram from the floppy NOT a bootloader ! and a REAL PROGRAM can size more than 512 words !
please correct my english errors
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Re: Floppy Partionning system

Postby VladVP » Thu Nov 07, 2013 9:13 pm

lamogui wrote:The goal is to boat a REAL PRogram from the floppy NOT a bootloader ! and a REAL PROGRAM can size more than 512 words !

A real program is loaded WITH a boot loader.
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Re: Floppy Partionning system

Postby Zardoz » Thu Nov 07, 2013 10:34 pm

lamogui wrote:The goal is to boat a REAL PRogram from the floppy NOT a bootloader ! and a REAL PROGRAM can size more than 512 words !


As I said the IBM PC BIOS loads a boot sector fro ma floppy or hard-disk. I had a 5" 1/4 floppy with the game of Donkey Kong. It was unreadable from DOS, forcing to boot the machine from these floppy and launching directly the game. Obviously the game was bigger that 512 bytes. More info : http://en.wikipedia.org/wiki/PC_booter
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Re: Floppy Partionning system

Postby S0lll0s » Tue Nov 12, 2013 1:39 pm

Zardoz wrote:
lamogui wrote:The goal is to boat a REAL PRogram from the floppy NOT a bootloader ! and a REAL PROGRAM can size more than 512 words !


As I said the IBM PC BIOS loads a boot sector fro ma floppy or hard-disk. I had a 5" 1/4 floppy with the game of Donkey Kong. It was unreadable from DOS, forcing to boot the machine from these floppy and launching directly the game. Obviously the game was bigger that 512 bytes. More info : http://en.wikipedia.org/wiki/PC_booter


Just let the DCPU have a 512 word BIOS, which could / should be flashed to load the first sector of a M35FD floppy (which just so happens to be 512w too).
If you want to, you can also flash a custom BIOS that loads the first X sectors, but thats not a very good idea.
If you ship a "vanilla" DCPU application (OS-less) just have the following layout:

Code: Select all
BIOS: 512w, moves itself into back of RAM, then loads sector 0 of floppy into start of RAM, then jumps to 0 (general)
floppy:
  0: Bootloader, moves itself into back of RAM, then loads whatever sectors the program needs (specific, i.e. 1,2,3) into RAM and executes them
  1,2,3: Program
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Re: Floppy Partionning system

Postby Zardoz » Tue Nov 12, 2013 2:37 pm

Image

BIOS size and boot sector size not are related. Are very different things, and the BIOS is placed in a ROM chip, not loaded from a floppy !!!!
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Re: Floppy Partionning system

Postby lamogui » Tue Nov 12, 2013 5:19 pm

why make things simple when we can complexify ?
please correct my english errors
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Re: Floppy Partionning system

Postby S0lll0s » Sat Nov 16, 2013 10:08 pm

Zardoz wrote:Image

BIOS size and boot sector size not are related. Are very different things, and the BIOS is placed in a ROM chip, not loaded from a floppy !!!!

I didn't say any of those things. Read carefully.
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