I used your code & it works like a charm. I organized the code into simple separate functions as shown below.
Now I'm having trouble figuring out a way to create a file using the above code. Could you please help me out here by giving me a point to start on working please ?.
---------- Post updated at 06:54 AM ---------- Previous update was at 01:41 AM ----------
Could Anyone Please Help me with this ?. I need to use the following code I've come up so far & figure out a way to create a file inside the block device. Following is my code.
Why are you opening and closing the file every time you do something?
This especially becomes useless:
...because the seek position gets reset every time you open it anyway. You should open it once and keep using the number it gives you. Your read code would end up looking like int readFromDisk(int fd, char *buffer,int length) { ... } iow exactly like normal read...so you might as well get used to ordinary read call instead.
You should also be doing something more with the number of bytes written and read than just printing it. read() and write() will occasionally surprise you with less than you asked for.
I just reorganized my code & came up with the following structure & it works like a charm. But I'm still having trouble creating a file inside the block device using the
method. Could you please point me from where I could get started. I want to simulate the working of the real os File Manager,which does it at the sector's level when writing a file to the disk. So I was wondering how could I use the above write method to achieve this. Could you please advice me on this as how may I proceed ?. Will I need to maintain a FAT like table when creating files so I could know in which sectors of the virtual hard disk the file is stored ?.
---------- Post updated at 11:48 AM ---------- Previous update was at 11:23 AM ----------
Hi dsw,
Thank you very much for your response. But what I need is to use the following method.
So I could simulate the working of the read file manager by creating a file @ the sector's level. I know I might sound ridiculous. But this is for a learning purpose & I would really appreciate if you could correct my approach if I'm wrong & guide me here .
The way you're using it, it contains no "files". A block device is nothing but a giant pile of undifferentiated blocks, ordered from first to last.
If you want to create a file in it, you have to know what type of partition it is, and follow that partition system's rules for how blocks are arranged into directories and files.
So you mean I should find how the ext3 (as I've formatted my loop back disk with ext3 with mkfs tool) creates files & directories on the hard disk drive ?. Is that approach correct ?. If yes where do you suggest I start reading on programming material for me to get started please ?.
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