QemuLator is one of those QL emulators which doesn’t really get the attention it
deserves. It comes in Windows and Mac OS X flavours and is somewhat unique in that it can run ordinary QDOS ROMs, or the more recent SMSQ/E versions of the operating system – the most recent Windows version can run the Gold Card, Aurora, or a special custom version for a Q60-compatible display mode. I only use the Windows version, so I am not sure if the OS X version can do all this.
Normally, my QL emulator of choice is QPC2. However, QemuLator gives me a means of testing my software on a QDOS ROM, and to run older software which may not run on QPC. QemuLator also has a configurable memory size, can be set to run at QL speed, Gold Card speed or as fast as your host computer can run. There’s a free demo version which has limited facility (lower maximum memory size, lower speed, etc) but is able to run smaller programs at QL speed, handy if you only use QL software occasionally.
Find out more about it at http://www.terdina.net/ql/q-emulator.html