For the 68020, a separate MMU (memory management unit) is necessary.
The EC models of the 68030, 68040, and 68060 are missing MMUs and
cannot run Linux.
For the 68020 and 68030, an FPU (floating point unit) is also
recommended. A kernel-level FPU emulator is on the verge of release
(as of this writing), but 68882 FPUs can be found for around U.S. $25 and
will improve performance with many applications. Users of the 68LC040
can also take advantage of the FPU emulator; however, many of the
68LC040 chips produced have bugs that make FPU emulation unstable.
Generally, the minimum RAM requirement is between 4 and 8 MB of RAM;
more RAM is generally better, though, and every little bit helps.
Amiga users should note that Linux cannot use chip RAM except
for the video, sound, and floppy drivers. The X Window System is
usually comfortable only with at least 12-16 MB of RAM and an
accelerated video card; however, it can run on the standard Amiga and
Atari video modes with less memory.
While you can probably install a minimal Linux system on a
20-30 MB partition, for any serious work you'll need over 100 MB,
including a separate swap partition. A useful approach is to purchase
the largest hard drive you can afford and install Linux on it, and
then watch it fill itself up. Many SCSI and IDE controllers are
supported on various platforms, although the support is not as
extensive as we would like because of the small developer base and
relatively expensive hardware (the least expensive Ethernet card for a
"big box" Amiga costs around U.S. $120!). All Amiga models are supported
by Linux if they have the right CPU. Clones that do not include the
Amiga's custom chips, such as the DraCo, are not supported at the
moment; other clones, such as the BoXeR, may or may not work (we have
not had any machines for testing).
Most 32-bit Ataris (ST/Mega ST/TT/Falcon) are supported although many
people have had trouble with the Afterburner040 CPU card. The Medusa
and Hades clones are also supported.
Macintosh models appear to be a hit-or-miss affair. Apple went
through many permutations of hardware in the m68k line and not all of
those permutations are currently supported; the porting work is
further complicated by Apple's reluctance to release documentation to
free software developers. In particular, Powerbook support is limited
because of the different ADB (Apple Desktop Bus) design on those
laptops. Even so, at least 27 Mac models are reported to have
keyboard, mouse, and display support.
VMEbus single-board computers from several manufacturers are
supported; these machines are widely used in industrial and research
applications. Motorola's MVME 147, 162, 166, 167, 172, and 177 are
currently supported, thanks to Richard Hirst. Richard has also ported
Linux/m68k to BVM Ltd's BVME 4000 and 6000 computers and the Tadpole
TP34V.
Other platforms have more limited support, due to a lack of people
working on porting Linux/m68k to those systems. For example, only 25
MHz NeXTs are currently working.