[Info-vax] Unix on A DEC Vax?

[Stephen Hoffman]

On 2013-01-17 22:30:41 +0000, Stanley F. Quayle said:

> Hoff, I don't understand what you mean when you say an emulator is 
> slow.  The various commercial emulators are faster than their physical 
> counterparts.  No, it's not a VAX running with a 3 GHz clock, but it is 
> still faster.
> 
> The important part is how well the customer's application runs.  A lot 
> of the big wins are in improved disk speed.  I have a customer 
> (www.stanq.com/wf1) that reduced their backup time by a factor of 8.  
> The only complaint was that the users thought the system was "too fast".
> 
> As for an emulator being a temporary fix, there are lots of customers 
> that rely on corner-cases in VAX floating-point operations.  They're 
> stuck on an emulator.
> 
> There are customers that have instruction-time dependence.  There are 
> hardware emulators for them (at least for VAX and PDP-11).  Expensive, 
> but if they really need it, they need it.
> 
> And there's a big chunk of my customers that want to get new hardware 
> but don't want to change anything.  Re-training users for some new 
> application can be really expensive.  And some have tried to develop a 
> Windows or Linux replacement, and failed horribly.
> 
> The FDA, FAA, DOD, NRC, etc. have been accepting emulators as valid 
> replacements for physical systems.  Re-qualifying an application can 
> cost thousands, if not millions, of dollars.


Barring cases where management or IT has painted itself into a 
financial or technical or political corner, would there be a 
substantial long-term role for emulators?  No.

Would most folks choose to load a server or a workstation with whacking 
great heaps of software overhead, given the choice?  No.

Is an application running via emulation going to be comparable[1] to 
native-built application code running on that same box; that is, with a 
native version of the application running without the emulator 
overhead?  No.

Will there be a groundswell of developers creating applications and new 
products for operating systems necessarily running on emulated 
hardware?  No.

Is emulation a good solution?   No.  But emulation may be the only 
viable solution.  I do know why folks use emulators.  Folks don't use 
emulators because they want to, or because an emulator provides them 
with a good solution.  Folks use emulators because they have to.  
Because they've gotten themselves tangled up somehow.  Maybe because 
the available hardware is not affordable or not reliable, or because 
management decided to consolidate on commodity platforms. or because 
some internal or external TLA or ETLA entity has regulatory 
something-or-other.

Emulators are a trailing-edge, stop-gap, make-due, 
paper-over-the-problem approach.

As for the emulation market, the folks that are choosing emulation will 
likely continue to use it until the application(s) age out, or the 
management involved ages out, or the organization gets clobbered by 
competition.  But those folks are probably not going to be doing very 
much with the applications running under emulation, as that's usually 
viewed as a dead-end for new investments, even within the organizations.

Hardware emulation is computing's version of the cover band.  Sometimes 
fun.  Variously useful.  But not really what most folks want.

Is there a market for selling solutions — whether emulators, or 
migration environments — into these tangled organizations?  Sure.

————

[1]There was a mention in this thread that a half-gigahertz Pentium box 
could do a reasonably fast VAX emulation, too.  Some apps can probably 
run faster on a smartphone than on a VAX system, too; smartphone 
graphics are far past what VAX typically offered, with more storage, 
and more RAM.  Is this a fair comparison?  No.



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