[net.micro.mac] Macintosh Plus: why not 12 Mhz

matthews@harvard.UUCP (Jim Matthews) (01/08/86)

	I got a peek at a Mac Plus yesterday, and it's pretty much
what the rumors have projected: an old mac with new ROM, a double-sided
drive, 1 Meg RAM, and a SCSI interface.  The modem and printer ports
are little round connectors, making room for the SCSI port.  The only
thing I found surprising was the way they fit 1 Meg onto the motherboard.
The RAM chips are on little strips of pc board (four of them, with 8 chips
each) which are mounted at a 45 degree angle to the main digital board.  I
just hope the ventilation is up to it.
	My one dissapointment was that they stuck with the 8 Mhz 68000,
instead of using the 12 Mhz model (which is used in the Laserwriter).
I can't see any technical or compatibility problem that precludes use of
the 12 Mhz chip, especially since a company is advertising (in Jan MacWorld)
a 12 Mhz daughter board for the Mac.  Would the 12 Mhz chip require faster
memory, or screw up some old software?  I was hoping that we wouldn't have
to wait for the 68020 Mac for significant speed improvements, but I guess
we will.

Jim Matthews
matthews@harvard

vishniac@wanginst.UUCP (Ephraim Vishniac) (01/09/86)

> 	I got a peek at a Mac Plus yesterday, and it's pretty much
> what the rumors have projected: an old mac with new ROM, a double-sided
> drive, 1 Meg RAM, and a SCSI interface...
> 	My one dissapointment was that they stuck with the 8 Mhz 68000,
> instead of using the 12 Mhz model (which is used in the Laserwriter).
> I can't see any technical or compatibility problem that precludes use of
> the 12 Mhz chip, especially since a company is advertising (in Jan MacWorld)
> a 12 Mhz daughter board for the Mac.

I've heard that the advertisement in question is a "marketing test."
In English, that means they threw in every feature they think *might*
be doable (never mind the cost) to generate interest.  I don't know
what (if anything) they actually have.
-- 
Ephraim Vishniac
  [apollo, bbncca, cadmus, decvax, harvard, linus, masscomp]!wanginst!vishniac
  vishniac%Wang-Inst@Csnet-Relay

dennisg@sdcrdcf.UUCP (Dennis Griesser) (01/16/86)

In reply to <593@harvard.UUCP> matthews@harvard.UUCP (Jim Matthews):

>	I got a peek at a Mac Plus yesterday, and it's pretty much
>what the rumors have projected: an old mac with new ROM, a double-sided
>drive, 1 Meg RAM, and a SCSI interface.  The modem and printer ports
>are little round connectors, making room for the SCSI port.

There had been rumors to this effect on the net.  Now they seem to be verified.
Apple has made all of our cables obsolete!  This is especially sad for the
special interfaces that clamp to the back of the Mac (like Assimilation's MIDI).

>                                                             The only
>thing I found surprising was the way they fit 1 Meg onto the motherboard.
>The RAM chips are on little strips of pc board (four of them, with 8 chips
>each) which are mounted at a 45 degree angle to the main digital board.   

The strips are called "SIP"s, for Single In-line Package.  They have been
available for a long time.  Various foreign and domestic companies offer them,
including TI.  You can usually get them with 4, 8, or 9 RAMs on a strip.  One
company puts 18 of them on, nine on each side.

>	My one dissapointment was that they stuck with the 8 Mhz 68000,
>instead of using the 12 Mhz model (which is used in the Laserwriter).

Don't forget that memory access is split between the CPU, video, and sound/IWM
systems.  Each area has its own time slots in the overall picture.  You DO need
faster RAM.  You would probably end up doubling the CPU clock and cramming two
CPU cycles into the current one, and leave the other stuff alone.  I suppose
that it is not a big problem, but just a bit more than Apple wanted to tackle
this time.  Hmmm, if the memory is twice as fast, you could speed up the video
part too and double the horizontal resolution.  But we need to keep the pixels
square...
-- 
[Standard disclaimers apply.]

carlile@trwrba.UUCP (Donald E. Carlile) (01/20/86)

In article <2584@sdcrdcf.UUCP> dennisg@sdcrdcf.UUCP (Dennis Griesser) writes:
>>are little round connectors, making room for the SCSI port.
>
>There had been rumors to this effect on the net.  Now they seem to be verified.
>Apple has made all of our cables obsolete!  This is especially sad for the
>special interfaces that clamp to the back of the Mac (like Assimilation's MIDI).
Apple is providing interface cables from the new DIN connectors to the old
DB 9 connectors.  This does not eliminate our old cables at all.

>--
>[Standard disclaimers apply.]

[for me too]

Don Carlile
...trwrb!trwrba!carlile