The earliest (available) version of Slackware.
KVM acceleration works well. I've used the cirrus vga device, though there's no X, so other devices would probably be OK too. The only emulated network adapter that I can get to work is ne2k_isa, and it even works with the default kernel without needing a custom kernel. :-)
Configuration in this pre-1.0 beta is different to even other very early versions of Slackware. You need to edit /etc/hosts and follow the instructions contained therein. For user mode networking in qemu I have the following lines:
10.0.2.15 darkstar
10.0.2.0 network
10.0.2.2 router
You also need to edit /etc/resolv.conf and change the IP address there to your nameserver. Under qemu I've got it set to 10.0.2.3
No web browser at all, but email clients and newsreaders are provided. I can't even get the ftp client to work with modern servers. But telnet still works with some servers, so some BBSs are possible to use, as long as their domain names resolve in this early version of Slackware.
Slackware pre-1.0 beta login screen
FTP can connect to a lot of FTP sites but don't expect all commands to work - even ls doesn't work.
Telnet can be used, for those sites that this version of Slackware can resolve domain names for.
