file transfer

[bsh152s]

Ok, this isn't a linux specific question but I felt this was the best place for the it. Anyway, I have a question about file transfer over the internet. I know that the size of a file on disk is different than the actual size of the file. In Win2k, it is in increments of 512 bytes. In *nix, is it any different? I don't have my Linux system in front of me, and I'm not sure how I could check anyway. Onto the question. When you are uploading/downloading files from the internet, are you downloading the size of the file on disk? Or, are you just downloading ... say 233 bytes (instead of 512)?

[Dagda]

You should only be downloading the size of the file not the size on disk.

[Bokkenka]

Think of it like sheets of paper. If you have to write a report for school, it can be measured out in sheets of paper. If you fill up five pages (sides of paper), you have used three sheets.

Let's say you have to read that report to a friend over the telephone so he can type it out for you. You read the report word by word. You have to transfer only the exact amount of words, not the blank space at the end of the last sheet. You don't even know how much blank space there will be, because that depends on what size paper your friend is using, how he has formatted the pages, and what size font he uses.

Blocks equal sheets of paper. Files equal different students' reports. And a hard-drive equals the teacher's briefcase. Each report has to be kept separate... Two files can't write to the same block. You can't fill the back of the last sheet of one student's report with the first page of the next. You might have forty-five pages of information. A page is half-a-sheet, so you actually have twenty-two-and-a-half sheets of information, but they might take up thirty sheets paper.

Now, the brief-case can only hold so many sheets of paper... A hard-drive has only so many blocks. If it can hold five-hundred sheets, the most reports you can have are five-hundred. Since reports have to be separate, each report might only have a couple short paragraphs on the front side of the sheet. There's lots of wasted space. If the teacher were to cut the sheets in half before handing them out, then she could have the same number of reports in half the space, so much of the wasted space could be recovered. If you lower the block size, you can fit a great number of files on a drive.

You can also lower wasted space by having larger files. A report fills up a full sheet before moving to the next. It's always the last sheet that has wasted space. If you lower the number of last-sheets, you lower wasted space.

Okay, the last couple paragraphs were extra info. I was on a roll. :)