jww@sdcsvax.UUCP (Joel West) (07/21/85)
A local company (see below) is now shipping their upgrade of a Fat Mac to 2mb
(i.e., added 1.5mb). I have no connection or interest in the company, and in
fact will probably wait for a 2mb Mac // next year, but thought some people
might be interested....
The techie I talked with, Duane Maxwell, said that his $900 (installed) upgrade
($500 if you populate and install yourself) is the only one so far that allows
you to use the entire 2mb for your programs. For example, it does allow the
use of the switcher with 4 512k applications; it does work with Jazz.
Apparently, the problem with doing a double 512k upgrade to 1mb is that some
programs write at, say 0x9abcd and read at 0x1abcd (relying on wrap-around),
unless you tell the software that this is a super-Fat Mac. Levco has been
working with Apple on this and apparently there is an "official" way to
support larger memory that programs should also follow.
In one of the cuter ideas, if worse comes to worse, your machine can go back
to being a "512". Apparently it's an option in the "bomb box" when you hit
the interrupt switch.
The upgrade comes with 4 prom sockets; only 2 are used, the other are for
your use and for later Levco products. By using the proms, they avoid
Apple ROM copyright problems, which a few other vendors allegedly face.
An external bus connector (non-virtual "slot") is available, and they
promise cooperation with anyone who wants to use this connector for their
own hardware development (SEAGATE, anyone?)
One interesting point--the extra 1.5mb of memory (Hitachi 150ns only) is
30% faster than the Mac memory. Why? Accesses to the 1st 512 are
interlaced between the 68000 and the video controller. I know Jobs loves
to save every penny, but I hope they address this issue on the next Mac
(of course, than means no video maps in the upper 1.5mb, but I can live
with that).
The upgrade is NOT compatible with:
1) Hyperdrive. No physical room, some software problems. They
might make it work, except he implied they will be introducing
a SCSI hard disk interface real soon.
2) Quark. Although the external Quark is fast as a Hyperdrive, the
code is so tight & timing-dependent that the 30% speed-up kills it.
The upgrade also includes an internal piezo-electric fan (held on with
velcro) which they will sell separately once they can get enough for
their memory boards.
Some dealers carry the Levco 512 upgrade already, and will get the 2mb.
Otherwise, contact Levco Enterprises, 6160 Lusk Blvd., Suite C-203,
San Diego, CA 92121--(619)457-2011. Ask to order the (groan) "Monster Mac".
All manufacturer's claims are unverified. Your mileage may differ.
--------
Joel West CACI, Inc. - Federal (c/o UC San Diego)
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