hardrive data question

[aceofskies05]

on a harddrive can the data of a program lets say bet scattered in differnt sections of a hdd or does it all have to be together, You know when you look at a cd and you can see the data burned into the disc well same with a hardrive,can data be like on seperate parts of the disc or does it all have to be in line

 

[Missing Ghost]

depends on the filesystem and on how much the data is fragmented. If you go in the windows defragmenter for example you can see how the data is scattered

 

[mrEvil]

easiest way to explain this is to take a look at FAT formatting, as NTFS is similar, just has security built in. FAT (file allocation table) format (DOS, Pre-Win2k, but still an option) uses an allocation table on the hard drive to keep track (pointers) to data locations.

Essentially, if you were to continuously keep writing to your HD without ever erasing from it, everything would be together and nothing would be fragmented..you'd just run out of room. However, since we tend to erase & copy things all the time, the drive has enough "brains" to keep track of, and squeeze in, parts of files that will fit in your free space..thus conserving space but fragmenting your HD. So, your data does not "all have to be in a line" - a contiguous file.

That's a simple, crappy overview, but what was I expecting to write at 1:45am anyway? My brain shut down a long time ago....hope it helps and sorry if I caused you any confusion.

 

[aceofskies05]

ok that helps , whats allocation table?

 

[Jeff7181]

Originally posted by: aceofskies05
ok that helps , whats allocation table?

Think of it as the "table of contents" for the data on the hard drive.

 

[sdifox]

Originally posted by: aceofskies05
on a harddrive can the data of a program lets say bet scattered in differnt sections of a hdd or does it all have to be together, You know when you look at a cd and you can see the data burned into the disc well same with a hardrive,can data be like on seperate parts of the disc or does it all have to be in line

It is far more likely for a file to be scattered all over the HDD. It's called fragmentation.

 

[nova2]

like Ghost said, it depends on the filesystem. (and how & how often the filesystem is used).

Daniel Robbins (drobbins@gentoo.org), President and CEO, Gentoo Technologies

OK, you may ask, what's the big deal? After all, ext2 filesystems take a long time to exhibit signs of fragmentation. However, I would argue that fragmentation is still a big problem, because although ext2 does not get fragmented easily, fragmentation is a one-way, cumulative process. That is, while ext2 fragments slowly, it cannot defragment itself. In other words, any often-modified ext2 filesystem will gradually get more and more fragmented, and thus slower. Even worse, there are no production-quality ext2 filesystem defragmenting programs currently available. This means that fragmentation is guaranteed to get worse over time, and the only way to fix it is to wipe the filesystem clean, and restore all the original files from a backup. That's a pretty involved and time-consuming process. So, how can the problem of fragmentation be dramatically reduced and contained? I'll cover all the juicy details in my next tip. See you then!

the wiki talks about fragmentation some with these FS, too:
http://en.wikipedia.org/wiki/ReiserFS
http://en.wikipedia.org/wiki/Xfs