Microsoft software from DreamSpark comes packaged in large, single files with .ISO or .IMG extensions. These files are “images” (exact copies) of the CD or DVD media on which the software would be shipped. (The name ISO refers to the standardized file format used for disc images.)
Since Microsoft software from DreamSpark often comes packaged in large ISO files (with file sizes on the order of gigabytes), downloading from the server with no download management system may cause your download to fail with no way to resume it. You may have experienced this if your connection timed out or if you ran out of disk space during a large download.
To address this issue, DreamSpark recommends the use of the Akamai Download Manager to steadily deliver the software to your computer. In the event that your connection to the server is reset, the progress you made on the download will not be lost.