Which Dec Emulation is the MOST useful and Versatile?

On 10/30/2017 06:18 AM, Eric Smith via cctalk wrote: As far as I know, IBM's 360s did NOT have any special purpose hardware associated with their emulation packages. The only thing special was that additional microcode cards were installed. In the 360/30, these were Mylar cards with word lines on them, they were punched on a card punch to punch out the capacitor plates to make zeroes. On the 360/40, they were Mylar "tapes" that were punched to cut traces to go through or bypass the sense transformers. On 360/50 and 65, they were etched word line boards that had traces that weaved under the bit line capacitor plates. So, these were all custom to fit the specific instruction set to be emulated. But, as far as I know, they added no additional logic to the machine to support the emulation. In some cases, this made things fairly inefficient. At least on the 360/30, when running 14xx emulation, there were many holes in memory, because they did not convert between decimal and binary addresses. So, memory locations 0-9 were used, A-F were inaccessible, 10-19 were used, 1A-1F were skipped, and so on. Some of this made I/O buffers kind of strange, as the I/O buffers had to be repacked between the real I/O devices and the emulator's buffers. Jon