Search found 9 matches

by brainbarshan
Tue May 11, 2010 8:04 am
Forum: Beginning OS Development
Topic: confusion in converting LBA to CHS
Replies: 1
Views: 5011

confusion in converting LBA to CHS

I am reading the tutorial 6 bootloader 4 chapter As written here : absolute sector = (logical sector / sectors per track) + 1 and the code written after this: xor dx, dx ; prepare dx:ax for operation div WORD [bpbSectorsPerTrack] ; divide by sectors per track inc dl ; add 1 (obsolute sector formula)...
by brainbarshan
Thu May 06, 2010 7:15 am
Forum: Beginning OS Development
Topic: why maximum number of files is 4,077 in fat12?
Replies: 4
Views: 7711

why maximum number of files is 4,077 in fat12?

In chapter 6 : Bootloaders 4
under the topic File system theory
Because of the limited cluster size, The maximum number of files possible is 4,077


why is this so? can you explain?
by brainbarshan
Tue Feb 23, 2010 6:54 pm
Forum: Beginners
Topic: Creating a bootloader
Replies: 3
Views: 12932

Re: Creating a bootloader

the kernel is being copied but is not executing
actually the system restarts when this instruction is reached:

Code: Select all

jmp   CODE_DESC:IMAGE_PMODE_BASE; jump to our kernel! Note: This assumes Kernel's entry point is at 1 MB
(from stage2 boot)
by brainbarshan
Tue Feb 23, 2010 2:27 pm
Forum: Beginners
Topic: Creating a bootloader
Replies: 3
Views: 12932

Creating a bootloader

I am trying to build a bootloader from the tutorial of operating system development series. i have a separate kernel file which i made earlier and used grub to boot it. I downloaded the Demo4 package from here and tried to use. The kernel file provided with the Demo4 package is being loaded. But whe...
by brainbarshan
Sat Feb 20, 2010 2:58 pm
Forum: Beginners
Topic: Confusion about media descripter byte in OEM block
Replies: 1
Views: 9805

Confusion about media descripter byte in OEM block

In tutorial 5 (Bootloaders 3) of operating system developement series : The Media Descriptor Byte (bpbMedia) is a byte code that contains information about the disk. This byte is a Bit Pattern: Bits 0: Sides/Heads = 0 if it is single sided, 1 if its double sided Bits 1: Size = 0 if it has 9 sectors ...
by brainbarshan
Fri Feb 19, 2010 4:55 pm
Forum: Beginners
Topic: confusion about segment offset addressing
Replies: 4
Views: 13827

Re: confusion about segment offset addressing

we are yet in real mode. how can we cross the 1mb th limit? will not it generate a fault? that is my confusion.
by brainbarshan
Fri Feb 19, 2010 1:20 pm
Forum: Beginners
Topic: confusion about segment offset addressing
Replies: 4
Views: 13827

confusion about segment offset addressing

hello...i am new to this site Here is my query: In Tutorial 4 of Operating System Development series (Bootloaders 2) there is a portion in segment offset addressing base address = base address * segment size (16) + offset 07C0:0000 = 07C0 * 16 (decimal) + 0 = 07C00 + 0 = 0x7C00 And in tutorial 5 at ...