info-mac@uw-beaver (info-mac) (09/12/84)
From: Thomas.Newton@cmu-cs-spice.arpa
>From the question & answer session for the 512K Introduction:
-------------------------------------------------------------
Q: What are the hardware differences?
A: Both Macintosh versions use the identical digital computer board. The
only difference between the two machines is the type of memory chip that is
installed in the board at the time of manufacture. In the case of the 128K
machine, sixteen 64K memory chips are installed. In the case of the 512K
machine, sixteen 256K memory chips are installed. The manufacturing process
and other components are identical.
Q: Do the Macintosh 128K and 512K systems look identical?
A: The systems look exactly alike except for two labels on the back of the
machines. The label for the 128K machine is printed "Macintosh." The label
on the 512K machine is printed "Macintosh 512K." The FCC label is different
for both machines.
Q: When will Expansion Kits be available?
A: On October 1, 1984.
Q: How is Apple taking care of early Macintosh customers who bought a machine
for $2,495, and now have to pay more than new customers to get the 512K?
A: Apple feels very strongly that it needs to support the existing set of
customers who were early buyers of the Macintosh 128K system. In order to do
so, when a customer purchases a Memory Expansion Kit, they are entitled to
receive a free copy of MacProject and MacDraw. These packages have a value
of $250. Thus, if a customer purchased a Macintosh before the price change
to $2,195 took effect, they are now getting the expansion and the software at
the same price as a customer buying those now.
To get the software, the customer must mail in their old system disk label to
Apple. They will receive their free copy of MacProject and MacDraw after they
have received a demonstration of the products from an Authorized Apple Dealer.
This offer, good only in the United States, is not available for customers
purchasing Macintosh's through the Apple University Consortium program.
Customers buying their 128K Macintosh after September 10 are not eligible for
the free software offer.
Q: How does Apple tell when a customer purchased their Macintosh?
A: The customer is required to mail system disk label to Apple, which has
encoded on it the date of manufacture.info-mac@uw-beaver (01/30/85)
From: Rich Cower <COWER@COLUMBIA-20.ARPA> anyone out there know if the 150ns chips can be substituted for the 200ns chips mentioned in the ddj article? i'm not enough of a hardware hacker to know. if interested - microprocessors unlimited at 918-267-4961 has the 150ns for 10.95 each. thanks...rich cower -------
info-mac@uw-beaver (02/01/85)
From: nate@cadmus (Nate Goldschag) Faster memory chips are always OK, assuming they are not weird chips. I upgraded mine with 150ns chips. I would advise reading a file I put on CompuServe in DL3 of MAUG titled FATMAC.HEX before doing it the Dr. Dobbs way - also DDWARN.TXT in the same place. Nate Goldshlag
info-mac@uw-beaver (02/01/85)
From: mazur@harvard.ARPA (Eric Mazur)
I would like to read your files about the 512k upgrade. Unfortunately I (and I
guess many others in ARPA land) don't have access to Compuserve. So could you please forward them to info-mac? Your help is very much appreciated (I'm
considering upgrading my Mac myself very soon now). Also, what does the 150 ns
stand for? Is it the access time (in which case they are better than the 200 ns
ones), or is it the refresh cycle time (in which case I would think that 150 ns
is awfully close to the 125 ns 8MHz clock rate on the Mac)?
Eric Mazur
Harvard University
ARPA: mazur@harvard
UUCP: {seismo,harpo,ihnp4,linus,allegra,ut-sally}!harvard!mazurinfo-mac@uw-beaver (02/04/85)
From: olson@harvard.ARPA (Eric Olson) My Mac has Hitachi 150ns chips. They work fine. Eric.
info-mac@uw-beaver (02/05/85)
From: nate@cadmus (Nate Goldschag) Eric- It is real hard for me to put the file on the net for various reasons. I sent a floppy with both files to Rich Cower so perhaps he can put them on the net. 150 ns memory chips refer to the access time from the RAS signal on the chip - the time after RAS when read data is available. So naturally 150ns chips are faster than 200ns chips and therefore certainly OK for an upgrade. Cycle time is something else. A 150ns chip can access in 150ns but there will be a time when RAS must precharge of perhaps 90 or 100 ns. So the fastest you can cycle a 150ns chip is about 240ns. Don't confuse that 4 Mhz cycle rate with the 8 Mhz 68000. The 68000 with no wait states takes 4 clock cycles to do a memory access so an 8 Mhz part has 500 ns to cycle - plenty of time.