[Info-vax] Vaxes shutting off this week

[JF Mezei]

Neil Rieck wrote:

> I was sad to see Digital switch from VAX go to Alpha until I worked on
> Alpha. While VAX was only 32-bit, addressing hardware extended the
> memory range to 40-bits (and maybe even higher?). Alpha addressing
> allowed for 64-bits of addressing. The Alpha CPU added other important
> features including IEEE floating point.

Remember that initially, VMS was still 32 bit on Alpha. And there are
still parts (RMS?) that are 32 bits.

Of all the major OS around, I think that OSF/Digital Unix/true 64 was
the only operating system that started off native 64 bits.  All the
others started life on architectures of less than 64 bits. (With windows
having roots on 16 bit machines with segment registers)

To me, the only significant difference is IEEE. If you get data from the
outside world in IEEE format, you can process it on Alpha "raw", whereas
on VAX, you need to call routines to convert it to VAX floating point
format.

Digital could have built VAX based machines with COTS components if it
had wanted to.  They could have added support for PCI bus if they had
wanted to etc etc.

Also, remember that at the VMS levels, the many improvements that we
have seen aren't due to Alpha per say, but rather the fact that Digital
slowed VAX development and did not implement all features on VAX-VMS.
But it doesn't mean that they couldn't have been implemented.