[Info-vax] OT: Computing Experience, What brought you to VMS?

[glen herrmannsfeldt]

already5chosen at yahoo.com wrote:

(snip)

> VAX has 64-bit floating point implemented in hardware. 
> And numeric properties of VAX FP formats are quite reasonable 
> even by today's standards. So, VAX 11/750 is not a fast number 
> cruncher, but has nothing to be ashamed of on precision side 
> of things.

The 11/730 had H-float as standard, it was an optional extra
for most other models, including the 11/750.

> On the other hand, CDC floating point arithmetic had reputation 
> for very bad numeric properties. Was it fixed in Cyber 200 series?

Makes sense if you consider what Cray did on the later machines.

There are many algorithms where close is good enough. If you are
a little careful, the deviations will average out, and many of those
need a fast processor. 

Remember the Cray machine with non-commutative multiply?

And the Cray-1 approximate reciprocal?

-- glen