If you have an original Windows 98 CD, you already have MS-DOS 7.1. You can boot from that CD and use the "Boot to DOS" option. Extracting the DOS files from a CD you own is legal under fair use/backup provisions (depending on your country).
: Support for file names longer than the classic 8.3 format when used with appropriate drivers. ms dos 7.1 iso download
was never an official standalone release from Microsoft. Versions 7.0 and 7.1 were part of Windows 95/98/98SE (7.1 introduced FAT32 support). Microsoft never sold or distributed MS-DOS 7.1 as a separate product. Therefore, no official ISO exists from Microsoft. If you have an original Windows 98 CD,
No. DOS is 16-bit and real-mode. It cannot run in 64-bit mode at all. ms dos 7.1 iso download