Released in March 1994, based on the Quadra case design the 6100 was the entry level Mac at the time. Originally running at 60mhz on a PowerPC 601 chip, it was later (January 1995) upgraded to 66mhz. It came in two varieties: the first was the av which included a video card in the PDS slot (allowing S-Video in, out and VGA) or the DOS compatible version (which had a 486/DX-2, SVGA out and support for up to 32MB of SIMM RAM) was released at the same time as the 66mhz. The former allowed the Mac to run on two displays (not sure about the latter as I only have an av), due to it's on board graphics card (although it only supports a maximum resolution of 832x624@256). It can be equipped with 8-264 megabytes of RAM and supports MacOS 7.1.2 to 9.1 (although good luck running anything more than 7.5.5 without lots of RAM), it also came with a 2x CDROM drive and a MACE on-board ethernet adapter.
Unfortunately (for me at least) the 6100 was produced after Apple moved to PowerPC, but before they changed to PCI so the internals are all NuBus. This means that most major linux distributions will not run on it (MandrakePPC, Debian/PPC etc), there are two options mklinux (developed by Apple) or Yellow Dog Linux (who do not support it but say that it might work). I have had success with neither although my 6100/av is extremely battered one and I'm surprised it still works at all. If anyone has got linux to work on their 6100 to work I would like to hear about it :) There is a project for kernels that support NuBus PowerMacs at http://nubus-pmac.sourceforge.net
All in all the 6100 is a decent machine for web browsing, mp3 playing and word processing. A couple of MacOS programs that run well(-ish) on my 6100 (and I use regularly) are: Netscape 4.7, Opera 5, Ircle, SoundApp (depends on QuickTime libraries for mp3 support) and MacPerl. I have been unable to get the S-Video to work yet (if anyone has done this please /msg me) but other than that it's a great little machine.
2004.2.27@5:56 joeystitch says (Re: Macintosh 6100) Actually, you can put as much as 520MB of RAM in the 6100 with 2 256MB EDO SIMMs. Lengthens the startup time by quite a bit, though. :-)