DEC had (at least) three workstation lines and they are very different beasts.
1. DECstation: MIPS CPU, running Ultrix, DEC's own traditional UNIX, despite CEO Ken Olsen's claim that "UNIX is snake oil."
2. VAXstation: VAX minicomputers in a workstation form-factor. Only later models had single-chip CPUs, I think: the earlier ones were multi-chip CPUs. The CISCiest of CISC processors in the 1980s/1990s. Could run VAX-VMS or various UNIXes as this is one of the original architectures Unix grew up on. So it can run Ultrix, or original BSD, or NetBSD, or older versions of OpenBSD, and others.
3. AlphaStation: 64-bit RISC microprocessor. Came in 2 firmware variants, one for VMS or OSF/1 Unix, and a different one for Windows NT.
The Alpha machines were an order of magnitude (or 2+ OOM) times more powerful than the DECstations, and there is no realistic hope of emulating them on an RP2040 or low-end Pi, machines considerably less powerful and capacious than the host.
1. DECstation: MIPS CPU, running Ultrix, DEC's own traditional UNIX, despite CEO Ken Olsen's claim that "UNIX is snake oil."
2. VAXstation: VAX minicomputers in a workstation form-factor. Only later models had single-chip CPUs, I think: the earlier ones were multi-chip CPUs. The CISCiest of CISC processors in the 1980s/1990s. Could run VAX-VMS or various UNIXes as this is one of the original architectures Unix grew up on. So it can run Ultrix, or original BSD, or NetBSD, or older versions of OpenBSD, and others.
3. AlphaStation: 64-bit RISC microprocessor. Came in 2 firmware variants, one for VMS or OSF/1 Unix, and a different one for Windows NT.
The Alpha machines were an order of magnitude (or 2+ OOM) times more powerful than the DECstations, and there is no realistic hope of emulating them on an RP2040 or low-end Pi, machines considerably less powerful and capacious than the host.