An AlphaStation’s SROM

The AlphaStation 500 is a workstation from Digital, circa 1996. Mine is a 500 MHz model and has an Alpha 21164A processor (aka EV56). And the way it boots is weird.

On your common-or-garden PC, there has always been some kind of ROM chip. It holds a piece of firmware known as the BIOS. This ROM chip is available at a well-known location in the processor’s address space (remembering that any PC processor boots up in 16-bit, 8088 compatible mode, with a 1 MiB address space, just like an IBM PC 5150) and the processor just starts executing code in it after reset.

The Alpha (or at least this AlphaStation 500 – although I think they mostly worked like this) is different.
↫ Jonathan ‘theJPster’ Pallant

A great read, but a little bit over my head considering I’m anything but a programmer or developer. Still, even I managed to get the basic gist and learn quite a bit from this article, and especially the part about how the AlphaStation uses a little jumper to tell the SROM exactly which stream of boot code to send to the processor is fascinating. I’m not sure just how unusual the Alpha’s way of booting is, but I’d at least never heard of it.