Between the physical disk and application is the file system. When creating a file system on a disk, you can minimize the total read time by increasing the block size of a file system. Doing this requires fewer total reads to read in a file. On ext2, the default block size is 1,024 bytes, but the maximum block size is 4,096 bytes. Maxing out block size has the drawback of increasing internal fragmentation.
All files use at least one block.
If a file is smaller than 4,096 bytes, it will still get one block, thus using 4,096 bytes minimum. Disk space tends to be cheap, so put in a larger disk and use maximum block size unless you know your average file size is significantly less than 4,096 bytes. This data usually isn't needed, and preventing access-time writes on a large set of files being served via a Web or another file server is worthwhile. Other factors, such as network-card idiosyncrasies, typical network load and other permutations of client and server software, may warrant other read and write block sizes. Hardware solutions are the simplest but can be expensive.