sterritt@ge-mc3i.UUCP (Chris Sterritt) (08/19/87)
Hello, I just got an upgrade to 2.5 Megs from Dove (which I adore), and a friend of mine just got a Mac II, with only a Meg. My question is, can I sell him the two 256K simms (since they'll at least fit in his machine) to upgrade him to 1.5 megs? Has anyone *done* this, or *know* of a reason why it won't work? Thanks, Chris Sterritt
wetter@tybalt.caltech.edu.UUCP (08/19/87)
In article <334@ge-mc3i.UUCP> sterritt@ge-mc3i.UUCP (Chris Sterritt) writes: >Hello, > I just got an upgrade to 2.5 Megs from Dove (which I adore), and >a friend of mine just got a Mac II, with only a Meg. My question is, can >I sell him the two 256K simms (since they'll at least fit in his machine) >to upgrade him to 1.5 megs? > Has anyone *done* this, or *know* of a reason why it won't work? HA! Another victim! No you cannot upgrade the Mac II to 1.5 Meg. The Mac II only allows memory sizes of 1,2,5,8 etc. I know this because some people here bought some upgrade kits to give themselves 3 meg. Now they are all upgrading to 5 meg. What you can do however is take _all_ of the 256K simms out of your Mac+ clip a resistor (maybe), add in another resistor (maybe), thus making your mac+ 2 Meg. The Mac II can now take all four of the 256K simms to give 2 meg. Hint for people upgrading Mac II's this is how to figure out what sizes are allowed. 4x256K simms = 1 meg 8x256K simms = 2 meg 4x1M simms = 4 meg but why would anyone bother since 4x1M + 4x256K simms = 5 meg one meg came with the machine 8x1M simms = 8 meg 8x2M simms = 16 meg when 2M simms are available 8x4M simms = 32 meg when 4M simms are available 32M + 6x16M per slot = 8x16M = 128 M but no video card Or maybe you would just like a HyperCube made of Macs over AppleTalk. True Story! Pierce Wetter! Where humor is concerned there are no standards -- no one can say what is good or bad, although you can be sure that everyone will. -- John Kenneth Galbraith -------------------------------------------- wetter@tybalt.caltech.edu --------------------------------------------
ephraim@wang7.UUCP (ephraim) (08/19/87)
In article <334@ge-mc3i.UUCP>, sterritt@ge-mc3i.UUCP (Chris Sterritt) writes: > a friend of mine just got a Mac II, with only a Meg. My question is, can > I sell him the two 256K simms (since they'll at least fit in his machine) > to upgrade him to 1.5 megs? > Has anyone *done* this, or *know* of a reason why it won't work? According to anything I've seen about upgrading the II's memory, the supported memory sizes are 1, 2, 4, 5, and 8 megabytes. The reason is that SIMMs are 8 bits wide and the Mac II data path is 32 bits wide. So, SIMMs must be installed in groups of four. You can have 4 256K SIMMs (1 Meg), 8 256K SIMMs (2 Meg), 4 1M SIMMs (4 Meg), 4 1M + 4 256K (5 Meg), or 8 1M (8 Meg). You can't have 6 256K SIMMs (1.5 Meg). In fact, you can't have any combination totalling 1, 2, 3, 5, 6, or 7 SIMMs, nor can you have any mixture except 4 and 4. -- Ephraim Vishniac masscomp!wang7!ephraim
olson@endor.harvard.edu (Eric Olson) (08/19/87)
In article <334@ge-mc3i.UUCP> sterritt@ge-mc3i.UUCP (Chris Sterritt) writes: > I just got an upgrade to 2.5 Megs from Dove (which I adore), and >a friend of mine just got a Mac II, with only a Meg. My question is, can >I sell him the two 256K simms (since they'll at least fit in his machine) >to upgrade him to 1.5 megs? My understanding is that SOME SE and Mac+ SIMMs are fast enough to use in a Mac II; others are not. Best bet is to try it before you take the guy's money. Does anyone know the maximum access times for the various Mac's SIMMs? -Eric Eric K. Olson olson@endor.harvard.edu harvard!endor!olson
dwb@apple.UUCP (David W. Berry) (08/20/87)
In article <3681@cit-vax.Caltech.Edu> wetter@tybalt.caltech.edu.UUCP (Pierce T. Wetter) writes: >In article <334@ge-mc3i.UUCP> sterritt@ge-mc3i.UUCP (Chris Sterritt) writes: >>Hello, >> I just got an upgrade to 2.5 Megs from Dove (which I adore), and >>a friend of mine just got a Mac II, with only a Meg. My question is, can >>I sell him the two 256K simms (since they'll at least fit in his machine) >>to upgrade him to 1.5 megs? >> Has anyone *done* this, or *know* of a reason why it won't work? > > HA! Another victim! No you cannot upgrade the Mac II to 1.5 Meg. The Mac >II only allows memory sizes of 1,2,5,8 etc. I know this because some people >here bought some upgrade kits to give themselves 3 meg. Now they are all >upgrading to 5 meg. Far from being a fluke or plot to sell more memory on Apple's part the reason the memory upgrades come in 1,2,5,8 combinations is that the 68020 has 32-bit wide memory. Thus memory must be added in 32-bit wide increments. This means you have to add or replace 4 simms (since each one is 8-bits wide) at a time. It's similar to why the Mac {plus,se} can only be upgraded to .5, 1, 2.5 or 4 meg. The 68000 utilizes 16-bit wide memory and thus must be upgraded 2 simms at a time. -- David W. Berry dwb@well.uucp dwb@Delphi dwb@apple.com 293-0752@408.MaBell