Search found 5 matches

by Master
Thu Dec 27, 2012 5:37 pm
Forum: General Programming
Topic: My Simple Operating system in Assembly
Replies: 1
Views: 27139

My Simple Operating system in Assembly

Hello . almost 2 and half years ago we tried to make a simple operating system for our system programming course using assembly. This Website and its tutorials were huge help for us . This is just a simple OS which only has FAT12 driver implemented .(The save function never got told in the tutorial ...
by Master
Sat Jul 10, 2010 7:15 pm
Forum: Beginning OS Development
Topic: whats the difference between 0xFF8 - 0xFFF in FAT12
Replies: 4
Views: 6962

Re: whats the difference between 0xFF8 - 0xFFF in FAT12

Hello, The FAT specification says that different disk utilities can use different EOC (End Of Clusterchain. ie, end-of-file) markers. While Microsoft uses 0x0fff for FAT12, it can be different. Because the BAD_CLUSTER marker is at 0x0ff7 for FAT12, its recommended to test between 0x0ff8 and 0x0fff ...
by Master
Sat Jul 10, 2010 7:14 pm
Forum: Beginning OS Development
Topic: saving a file in fat12
Replies: 1
Views: 4645

saving a file in fat12

hello all , im trying to save a file in fat12 structure . the loading procedure is given in the tutorial but the saving procedure is not . i myself came up with some sort of algorithm which im not sure of its correctness yet . can you verify its integrity ? you know , i dont know exactly how to go a...
by Master
Fri Jun 25, 2010 10:36 am
Forum: Beginning OS Development
Topic: whats the difference between 0xFF8 - 0xFFF in FAT12
Replies: 4
Views: 6962

Re: whats the difference between 0xFF8 - 0xFFF in FAT12

could it be that because 0xFF8-0xFFF equals 4088-4095 which exceeds the number of actual clusters usable in Fat12 structure ? i mean because starting from 0xFF8 means the cluster you are looking for doesn't exist , ( or you have passed the boundary which specifies the last usable cluster in FAT12) (...
by Master
Fri Jun 25, 2010 6:36 am
Forum: Beginning OS Development
Topic: whats the difference between 0xFF8 - 0xFFF in FAT12
Replies: 4
Views: 6962

whats the difference between 0xFF8 - 0xFFF in FAT12

hello all , as you see in FAT12 , it says 0xFF8 - 0xFFF are used to indicate the Last cluster in file, my question is , why do we have this range for specifying the end of file!!? and why cant we use those last addresses for our clusters ? we could easily use 0xFFF as the indicator (or vice versa), ...