[Info-vax] OpenVMS I64 V8.1 "Evaluation Release"?

[Michael Kraemer]

John Wallace schrieb:

> 64bit application design does not require >4GB of RAM, though more RAM
> may often be helpful for performance. 

For a high-end chip like the Alpha (and the other RISCs too),
it's the *only* way to get performance for large problem sizes,
isn't it?

> But even with less than 4GB of
> memory, it's often easier for some apps to be designed to assume a
> 64bit virtual address 

such as?

> and let a decent OS worry about mapping virtual
> memory to physical memory.

That's what 32bit systems do too.
But what happens when you do a calloc( 5GB ) on a 64bit system which
has only 256MB real RAM?

> "If one really desperately needed >4GB, one could just as well have
> chosen one of the mature 64bit RISC platforms."
> 
> Such as? With what OS? If you really wanted flat 64bit addressing, for
> a long time Tru64 was the answer (even if it wasn't called that at the
> time).

By the time Itanics became at least marginally usable (around 2001),
all RISC platforms had 64bit for quite some time, both in hardware
and OS. HP and IBM turned 64bit around 1997/98, i.e. long before
Merced even existed in silicon. SGI's IRIX went 64bit around 1994/95,
and their hardware had 64bit CPUs even before Alpha.
But early 64bit features are more are less moot,
since there was no appropriate hardware to support them,
i.e. enough (and affordable) RAM. For example, in 1993 DEC
offered us bread-and-butter Alpha's like the AXP 3000
with 256MB and 2GB disk(s). That's far from 64bit
and not any different from what the 32bit competition had back then
(and not faster nor cheaper btw).

So if one wanted/needed 64bit, it wasn't necessary to wait
for IA64, nor was Tru64 the only horse in town.