Aliados is a CP/M 80 emulator. Instead of emulating a machine and running some variant of CP/M on it, it emulates only the microprocessor and captures all CP/M system calls to execute natively. It does not need to create disk images, but reads and writes on the native filesystem all files that match the CP/M naming conventions.
ADTPro transfers disks to and from Apple II and Apple /// computers and the modern world using any of these communications methods: serial/USB, UDP via the Uthernet or LANceGS Ethernet cards, or audio via the Apple's cassette ports. ADTPro has comprehensive bootstrapping support for otherwise diskless Apple IIs. The home page includes extensive tutorials for getting started.
AtariSIO is a Linux kernel driver module plus a small set of tools that implement the Atari 8-bit (400/600/800/XL/XE) computer series SIO protocol. The kernel driver handles the low-level parts and provides a simple interface for user space applications. This package contains two tools: atariserver, an Atari disk drive emulator (similar to SIO2PC or APE for MSDOS), and atarixfer, a tool to transfer disk images to/from a connected Atari disk drive.