Mac Plus - Identify this Memory Expansion

[68kPlus]

What a strange but cool product - and an interesting piece of history - back when people were trying to find cheaper ways to upgrade I guess

 

[Iesca]

Fascinating. So it really was just a (complicated) SimmSaver-type device?

 

[TechnicalAirGap]

Thank you so much for this information. No idea how long I scoured Google Images looking for something that looked even close. Interestingly, the attached Datasheet from @MacOSMonkey says that the installation includes a piezo fan. No such fan was installed in this machine. Once I work out how to get an OS onto the machine (currently messing with re-formatting a HD floppy to 800k - not going so good), I will see what the machine reports for its memory. I do have a ZuluSCSI, but just need to get the DB25 connector and cable to connect to the Plus.

Thank you once again.

Steve

 

[4seasonphoto]

Fascinating. So it really was just a (complicated) SimmSaver-type device?

Pretty much. I don't remember what 1 MB SIMMs cost in the 1980s, except that they were serious money.

 

[TechnicalAirGap]

Yes, the Mac Plus is indeed reporting 2Mb of RAM. There seems to be no other indication of that RAM expansions impact on the system. Seems to work as fast (or slow) as a Plus would.
I did work out a way to make a *reasonably* reliable 800k disk from a standard 1.4Mb HD one. As the issue seems to be the coercivity of the newer HD media (essentially the magnetic field required to write onto a HD disk needs to be a LOT more than to a DD 800k disk). Any residual data on the HD floppy written by a previous corresponding HD drive is difficult for a DD 800k drive write process to overcome. By using a tape head demagnetizer to completely erase the HD floppy beforehand, and therefore removing any residual magnetic imprint, the drive was then easily able to format and write to the erased floppy. Taping over the HD hole on the back of the disk tells the Mac drive that it is a DD 800k disk.
I formatted about 8 HD disks this way, only one required a second erasure with the demagnetizer.
I was then unpleasantly amazed at how often you need to swap disks between the system disk and the application... holy cow.

Thanks again,

Steve

 

[MacOSMonkey]

Use a Floppy Emu in HD20 emulation mode.

I may also have one other bit of marketing info on the 1+1, plus maybe some tech info and Q&A. I am remembering a bit more after thinking about this stuff.

 

[LaPorta]

Yes, the Mac Plus is indeed reporting 2Mb of RAM. There seems to be no other indication of that RAM expansions impact on the system. Seems to work as fast (or slow) as a Plus would.
I did work out a way to make a *reasonably* reliable 800k disk from a standard 1.4Mb HD one. As the issue seems to be the coercivity of the newer HD media (essentially the magnetic field required to write onto a HD disk needs to be a LOT more than to a DD 800k disk). Any residual data on the HD floppy written by a previous corresponding HD drive is difficult for a DD 800k drive write process to overcome. By using a tape head demagnetizer to completely erase the HD floppy beforehand, and therefore removing any residual magnetic imprint, the drive was then easily able to format and write to the erased floppy. Taping over the HD hole on the back of the disk tells the Mac drive that it is a DD 800k disk.
I formatted about 8 HD disks this way, only one required a second erasure with the demagnetizer.
I was then unpleasantly amazed at how often you need to swap disks between the system disk and the application... holy cow.

Thanks again,

Steve

Or you can get a relatively cheap external 800k drive?

 

[s_pupp]

In college, I had a Mac Plus with 1MB RAM and no peripherals. I minimized disk swapping by putting a system folder on each disk. When it wasn’t possible to do so, I used RamDisk+ (I think that was the name) and put a system folder on it. I forget exactly how, but there is a way to change which system you are using by perhaps pressing command-option and double clicking on the finder on the disk you want to use, or something similar. The RAM disk, of course, would reduce the amount of available RAM.

An external floppy drive would definitely improve the Mac Plus experience, in absence of a hard drive.

 

[Phipli]

I forget exactly how, but there is a way to change which system you are using by perhaps pressing command-option and double clicking on the finder on the disk you want to use, or something similar.

Yup, that's right :

 

[MacOSMonkey]

Attached are some old 1987 ads for the SuperMac SuperRAM2, SuperRAM4 and Enhance.

In terms of fans, the MacPlus is very easy to cool. Just open the case, velcro in a couple of modern fans on the inside upper vents and wire them to 5V. If you want to slow them down, put a pot or resistor in series. If you want to be fancy, you can mod the case and put the pot knobs on the outside...or hang the pot(s) outside the case. Slow-speed/low-noise fans are a good idea on early Macs. They were under-cooled and often developed power supply issues over time (also cap aging, etc.).

If you only want to use 1 fan, the put it on the power supply side and tape off the upper vent on the opposite side so that you can direct airflow.

 

[LaPorta]

Yup, that's right :

Same thing to switch to MultiFinder on the same disk. Can’t switch back, though.

 

[TechnicalAirGap]

Use a Floppy Emu in HD20 emulation mode.

I may also have one other bit of marketing info on the 1+1, plus maybe some tech info and Q&A. I am remembering a bit more after thinking about this stuff.

I do have a Floppy Emu, but its currently wired into my //c. I do have a ZuluSCSI, but I am yet to work out if it can do the simple file transfer like the BlueSCSI on which its based. I'm not sure if it can, and I don't want to go to the trouble of creating HD images just for random program transferring. If anyone knows if the ZuluSCSI can do file transferring in a simple way like the BlueSCSI, I would love to know.

 

[TechnicalAirGap]

Or you can get a relatively cheap external 800k drive?

I am currently looking for an external floppy or HD (Macintosh original, not 3rd party) for the Plus.

I have also ordered another 2x 2Mb RAM SIMMS, to put into the system. I might get a total of 4x and do away with the 3rd party RAM expansion. If anybody is a collector and would find value in owning it, I would gladly swap it for an external HD or Floppy for the Plus..?!?

 

[LaPorta]

I am currently looking for an external floppy or HD (Macintosh original, not 3rd party) for the Plus.

I have also ordered another 2x 2Mb RAM SIMMS, to put into the system. I might get a total of 4x and do away with the 3rd party RAM expansion. If anybody is a collector and would find value in owning it, I would gladly swap it for an external HD or Floppy for the Plus..?!?

I may have one that would work for you. Send me a PM.

 

[MacOSMonkey]

There are a bunch of stock boot images online for all the different emulators, including blank volumes (or take LaPorta up on the offer). No need to create them. Also, maybe consider getting another Floppy Emu so that you can have one dedicated to the Mac side...or even just for that machine.

 

[TechnicalAirGap]

There are a bunch of stock boot images online for all the different emulators, including blank volumes (or take LaPorta up on the offer). No need to create them. Also, maybe consider getting another Floppy Emu so that you can have one dedicated to the Mac side...or even just for that machine.

Yes, I have used a few of those stock images for the ZuluSCSI. But unless I am mistaken, I believe that you cannot just drop a single "program" onto the ZuluSCSI SD card unless its an image of some sort. This would mean that you have to create an image containing that program in an emulator, and then save that image as a .hda that can be placed on the SD card and read by the ZuluSCSI. Is this correct? I believe that Blue SCSI have a way to transfer single programs that are not imaged, but not on the ZuluSCSI. I am more than interested to know if ZuluSCSI also have this facility.

 

[bigmessowires]

There seems to be no other indication of that RAM expansions impact on the system. Seems to work as fast (or slow) as a Plus would.

Adding more RAM won't speed up the computer (unless maybe if you enlarge the disk cache in the Memory control panel). The main benefit is that you can run programs that require more RAM and that you couldn't run otherwise. Or you can run multiple programs at once under Multifinder.

 

[TechnicalAirGap]

Adding more RAM won't speed up the computer (unless maybe if you enlarge the disk cache in the Memory control panel). The main benefit is that you can run programs that require more RAM and that you couldn't run otherwise. Or you can run multiple programs at once under Multifinder.

Hi BMOW,

Yes, agreed. I should have said that I didn't notice any other impact on the system from this card, other than it adding the extra RAM. It didn't require any CP items, or drivers of any kind. Seems to be quite transparent to the system. Memory must have really been quite expensive back then, if it was cheaper to buy this and use your existing SIMMs than to just buy larger SIMMs. There is some effort now required in removing the Logic Board from the frame, it no longer just slides out. I guess these were installed by dealers back then.

 

[MacOSMonkey]

You can "easily" create and modify disk images using one of the retro emulators -- like SheepShaver or Basilisk II. I say easily, because there is a slight learning curve for installing the emulators and then figuring out how to make, select and modify images -- but not too bad. Since you have a ZuluSCSI, it might be reasonable to assume that you already have one of those environments set up on a modern Mac or PC. If not, then install one of them, get the blank placeholders and build your own images. Also, consider a FloppyEmu in HD20 mode and slap it on the external floppy port. Anyway -- up to you.

The SuperMac OnePlusOne was far cheaper than standard upgrades because of the fact that it used 256Kx8's vs. 1Mx8's. If you wanted 4Mb in a MacPlus in 1987 using 1Mbx8, it would have cost $2K+. You could probably get crappy 1Mb modules for $400ish (for a total cost of $800ish) -- or maybe cheaperr if double-sided, but the good ones (and Apple's) cost more -- $5-600+ IIRC. If you wanted to go to 2.5Mb, it would have cost $1K+ (because you had to replace the default 256K modules with 1Mb ones). The 4Mb upgrade cost more than the entire computer -- that was the problem in the early days of the personal computer.

The MSRP for the SuperMac OnePlusOne was only $399ish. It may have had a price reduction over time to continue to offer some value/profit. It let you keep your 256K's and added another 1Mb. So, it was less than half the cost of a regular 2Mb MacPlus upgrade and let you still use the RAM sockets for a later upgrade. That is the reason it existed. It even beat out the crappy 1Mb module upgrades. It was an easy win as long as RAM prices remained high (which they did for a reasonable amount of time).

Otherwise, in our current timeframe, the main point of interest is as a clever SuperMac hardware hack that was one of the products that helped launch the company.

 

[TechnicalAirGap]

I will definately look into one of the emulators that will allow me to build custom .hda images, yes. I do have a floppy emu, its lust wired into the internal FD port of my //c at the moment. I might mess with that also.