Back in 1984 the Apple Macintosh began using a new disk format. Atari soon followed with the release of the Atari 520ST computers. These new diskettes were encased in a hard plastic shell with a protective metal sliding door to keep users from touching the disk contained within. Unlike the old 8" and 5.25" FLOPPY disks, these new 3.5" Micro-Disks were much more durable and reliable. Also these new disks could hold up to 1.44 megabytes of memory. That was equivalent to just over 16 Atari 810 floppy disks. The whole computer industry was starting to jump onto the 3.5" bandwagon so Atari began work on a new 3.5" disk drive for its 8-bit XE line of computers called the XF351. Most software manufacturers were moving away from the 8-bit line of computers and onto the new 16bit systems, and most companies would not produce their software in both 5.25" and 3.5" format so Atari decided to scrap the project and the XF351 disappeared along with many other promised projects for the Atari XE's such as the XC1411 color monitor, the XM128 monocrome 80 column monitor and the XTM201 thermal printer.
This new 3.5" floppy drive used the same mechanism as the SF354 floppy
drives on the ST computers, the case was also the same with the exception
of the rear of the drive case which has 2 SIO ports, power, power switch
and drive select switch. The above shown unit is #39,
the drive controller is labelled XF351 on one of the capacitors and on
the bottom of the drive case are handwritten instructions on setting the
drive number. The unit performs well and is faster then the
XF551 disk drive, burst mode has not been tested. The
drive had to be set as #2 and the system was booted from a standard 5.25"
disk drive using MYDOS 4.5, a standard 720K Atari disk was then formatted
with DOS.SYS and DUP.SYS installed, then the drive was changed to #1 and
the unit boots up an Atari 130XE perfectly.