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| Booting from network http://forums.osdever.net/viewtopic.php?f=15&t=916 |
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| Author: | juanma268 [ Wed Feb 02, 2011 9:40 am ] |
| Post subject: | Booting from network |
Hello all, i am new here and this is my thirt post. Using the Gregor Brunmar tutorials I have made a ".img" disk image (of my toy OS) that can boot the pc and print "Hello World!" in the screen. For do that i copy the image (2 boot sectors + kernel) to my usb drive or floppy using WinImage. But i have a problem booting the image from the network using the PXE environment because it has not file format. I will explain: A program named "3Com boot image editor" let me modify the ".img" images and make them "network booteable". The procedure is load the image to floppy, run the application, save the resulting image in another place and use FTPD32. I have made images from win98 recovery floppy disk and bart's net disk, loading this images into floppy drive i am capable of explore the files inside them. When i use the 3Com program with my Os ".img" file it says "There are no files in the floppy disk", so i guess that the problem is produced because i have made an image with no file format header. So the question is: how can i add format to my Os image? Does someone has a good idea? Thank you. |
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| Author: | losethos [ Wed Feb 02, 2011 4:28 pm ] |
| Post subject: | Re: Booting from network |
If you are asking the format of floppies, it's usually known as "FAT12". Try google searching that. It's a pitty spending time on that format since floppies are obsolete, but that might be the easiest. You could try to get CD-ROM ISO9660 working. It's slightly more complicated. |
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| Author: | juanma268 [ Wed Feb 02, 2011 9:29 pm ] |
| Post subject: | Re: Booting from network |
Thank you Losethos for the answer. I was surfing in Google and i have written a little table for fat12, but with no success yet. Here the code. Code: [BITS 16] ; We need 16-bit intructions for Real mode [ORG 0x0] ;TABLA FAT12 jmp start ;3 bytes oem db "........" ;8 bytes bytespersector dw 200h ;2 bytes, 512d sectorspercluster db 1 ;1 bytes reservedsectors dw 1 ;2 bytes totalfats db 2 ;1 bytes maxrootentries dw 224d ;2 bytes, 240d totalsectorssmall dw 0b40h ;2 bytes, 2880d mediadescriptor db 0f0h ;1 bytes sectorsperfat dw 9h ;2 bytes sectorspertrack dw 12d ;2 bytes numheads dw 2d ;2 bytes sectoresOcultos dd 0 ;4 bytes longitudTotalSect dd 0 ;4 bytes driverNumber db 0 ;1 bytes flags db 0 ;1 bytes signature db 29h ;1 bytes, 41d id dd 0ffffffffh ;4 bytes volumelabel db "JMFDOS......" ;12 bytes, 4294967295 systemid db "FAT12..." ;8 bytes ;[ORG 0x7C00] ; The BIOS loads the boot sector into memory fixed location 0x7C00 start: mov ax,0x7c0 mov ds,ax ;(the rest of the bootstrap...) With this code i get a non booteable image that after mounted in the floppy can not be readed. When i uncomment "[org 0x7c00]" and erase the 2 lines after the "start" label and quit the diretive "[org 0x0]" in the first line the image works (like in the past). Sorry for my english. Is there something wrong with the fat12 table? |
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| Author: | ~ [ Wed Jan 22, 2025 4:23 am ] |
| Post subject: | Dating for Sex. |
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