[comp.sys.mac] '030 daughterboard possible?

mcdonald@fornax.UUCP (Ken Mcdonald) (03/22/89)

There is a current wave of Apple price/upgrade bashing going on the net,
started by a posting put out by me complaining about the hight upgrade
cost of II->IIx.  I still stand by this complaint, but would like to make
one further note, and ask another question.

One of the biggest disappointments to me in terms of Apple's upgrade
behaviour concerning the Mac II was the implicit soft shoe routine they
pulled by putting a PMMU socket on the Mac II board, and then never releasing
a Mac II with a PMMU, but instead going to the '030 WITHOUT PROVIDING A SIMPLE
DAUGHTERBOARD EXPANSION to retrofit an '030 to the Mac II.  I can't see any
technical reason it can't be done, it would give you essentially a IIx (call
it a IIx/2?) at a far lower price than a motherboard swap, and it wouldn't cost
anymore than buying a PMMU for the II.  The advantages are that you sidestep any
weird campatability problems arising from the differences in the PMMU's, and
you don't have the penalty of an extra wait state.  Of course, if there are
technical reasons why a daughterboard like this can't be produced (which is my
question, natch--is this feasible), then flame on.  Otherwise, flame Apple.

As usual, please disregard the typos--I'm just too lazy to fix them.

Ken McDonald

tecot@Apple.COM (Ed Tecot) (03/30/89)

In article <933@fornax.UUCP> mcdonald@fornax.UUCP (Ken Mcdonald) writes:
>One of the biggest disappointments to me in terms of Apple's upgrade
>behaviour concerning the Mac II was the implicit soft shoe routine they
>pulled by putting a PMMU socket on the Mac II board, and then never releasing
>a Mac II with a PMMU, but instead going to the '030 WITHOUT PROVIDING A SIMPLE
>DAUGHTERBOARD EXPANSION to retrofit an '030 to the Mac II.  I can't see any
>technical reason it can't be done, it would give you essentially a IIx (call
>it a IIx/2?) at a far lower price than a motherboard swap, and it wouldn't cost
>anymore than buying a PMMU for the II.  The advantages are that you sidestep any
>weird campatability problems arising from the differences in the PMMU's, and
>you don't have the penalty of an extra wait state.  Of course, if there are
>technical reasons why a daughterboard like this can't be produced (which is my
>question, natch--is this feasible), then flame on.  Otherwise, flame Apple.

Actually the early IIx prototypes were daughterboards.  They proved to be
unreliable and could not be FCC or (the european equivalent) approved, making
them difficult to impossible to sell.  Instead, the hardware design team
chose to recommend 68851s to current Mac II owners, for greater reliability
at a lower price.

						_emt

ra_robert@gsbacd.uchicago.edu (03/30/89)

In article <28063@apple.Apple.COM>, tecot@Apple.COM (Ed Tecot) writes...
> 
>Actually the early IIx prototypes were daughterboards.  They proved to be
>unreliable and could not be FCC or (the european equivalent) approved, making
>them difficult to impossible to sell.  Instead, the hardware design team
>chose to recommend 68851s to current Mac II owners, for greater reliability
>at a lower price.


OK, I know this is entering iffy territory, as far as disclosure, so feel free
NOT to reply if you can't, but will features available in system releases in
the near future (next 18 months) be equally accesible to II/PMMU owners as they
are to '030 owners (just from a chip point of view, leaving out any new
hardware coming out soon/in the future).



Robert
------
ra_robert@gsbacd.uchicago.edu
------
generic disclaimer: all my opinions are mine

tecot@Apple.COM (Ed Tecot) (03/30/89)

In article <2530@tank.uchicago.edu> ra_robert@gsbacd.uchicago.edu writes:
>OK, I know this is entering iffy territory, as far as disclosure, so feel free
>NOT to reply if you can't, but will features available in system releases in
>the near future (next 18 months) be equally accesible to II/PMMU owners as they
>are to '030 owners (just from a chip point of view, leaving out any new
>hardware coming out soon/in the future).

It's my understanding that the 020/851 pair's instruction set is a superset
of the 030.  If this is in fact true, it's probably impossible that any
system release could possibly do anything but provide the same features.
As a matter of fact, some software had the opposite problem (A/UX 1.0 and
Connectix' Virtual 1.0); they worked only on 020/851 machines, not 030s.

						_emt