Ersatz-11 is available for Linux, as well as for DOS and Windows. In common applications, this version achieves substantially better performance than E11 for DOS or Windows, thanks to the excellent disk caching and reliable scheduler found in Linux. In addition, Linux's rich device-independent support for serial, Ethernet, and mass storage devices means that E11/Linux will work with a wide variety of hardware without depending on the fixed number of drivers built in to E11.
The tight coupling to the PC hardware in the DOS version of E11 gives it the ability to do a number of things which are not currently possible on E11/Linux. However, many of these issues (such as RX50 floppy disk support) will be addressed in upcoming updates (which are free for the first 12 months after purchase), while others (parallel port "blinky lights" display register boards, VT11 vector graphics scope) have proven to be of little interest to E11 users anyway.
On the other hand, E11/Linux makes heavy use of threads, so that I/O to disk and tape image files is truly asynchronous, unlike the DOS version which has to pause PDP-11 instruction execution briefly during image file I/O. So throughput is higher and latency is lower, on E11/Linux. This benefit is even more apparent on SMP Linux machines, where the PDP-11 instruction emulation thread can run pretty much flat out on one CPU while the I/O helper threads do their small amount of processing on the other CPU(s).
Existing E11 customers may upgrade their licenses for E11 for DOS to the Linux version at any time by paying only the difference in the current prices. E11/Linux is currently priced at US $3,999 for the first copy and US $1,999 for each additional copy (used by the same end user).