Concurrent writes to 1 HDD: fragmented or sequential?

[westrock2000]

I have wondered this. If you write two seperate files to the same Platter drive at the same time, and assuming Windows, do the file blocks get interwoven as they are received to the HDD which fragments the files or does the OS allocate a block of space for the first file and then allocate a block of space for the second file so that they are both stored as sequential data?

 

[BecauseScience]

Modern implementations of NTFS utilize Extent Based Allocation so the answer is no, the blocks for the files are not interwoven. I tried to find a decent link that describes the technique but couldn't. Basically, with extent based allocation, rather than allocating space a single block at a time, contiguous chunks of blocks are allocated. These chunks are called extents. Extents are much, much larger than the block size.