21 Feb
2018
21 Feb
'18
11:32 a.m.
Guy Sotomayor Jr via cctalk writes:
I'd like to echo this, depending on the caching and the behavior of the
system. In writing the 3B2/400 emulator, I was at first reluctant to
write an accurate emulation of the MMU cache, feeling it unnecessary. I
very quickly learned that it was not only necessary, but essential to a
correctly running system. Moreover, it had to have the same caching
algorithm as the real hardware to get UNIX SVR3 running happily.
On Feb 21,
2018, at 10:59 AM, Paul Koning via cctalk <cctalk at classiccmp.org> wrote:
Caching doesn't change user-visible functionality, so I can't imagine
wanting to emulate that. The same goes for certain error handling.
I've seen an emulator that included support for bad parity and the
instructions that control wrong-parity writing. So you could run the
diagnostic that handles memory parity errors. But that's a pretty
uncommon thing to do and I wouldn't bother.
I disagree, especially if you?re using an emulator for development.
Caching is one of those things that can go horribly wrong and not
having them emulated properly (or at all) can lead to bugs/behaviors
that are significantly different from real HW. TTFN - Guy
-Seth
--
Seth Morabito
https://loomcom.com/
web at loomcom.com