Macintosh II - Page 1
Forum section: electronics / general

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 28, 2024, 07:05:04 pm
content: Thinking of getting a Mac II for nostalgic reasons. Never had one but only came close in stores as a kid...What's the best forum for getting all information from screw sizes to ROM images?Because I've seen a lot of Mac IIs on eBay but they all seem to need work.Is the Mac II ROM still under Apple copyright? I assume so.I want to make a functional 020 based machine with Ethernet access with period correct hardware.Is it feasible for under 1000$ CDN?

author: abeyer
author_rank: Frequent Contributor
timestamp: January 28, 2024, 07:53:59 pm
content: Quote from: Alex Eisenhut on January 28, 2024, 07:05:04 pmLiterally the first listing I see is a fully functional recapped system listed for $420 usd for everything but the ethernet card & transceiver... so, yeah, seems easy enough to stay under that budget.

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 28, 2024, 09:27:50 pm
content: I have all Apple Mac ROMs. Don't remember for sure where I got them from, but you can find them here:https://www.macintoshrepository.org/7038-all-macintosh-roms-68k-ppc-They do work. You can test them with an emulator - for the 68K ROMs, Basilisk II works well.I don't remember what's Apple's position regarding these, but I would assume they don't care much, especially if you're not going to make a business out of it.

author: brucehoult
author_rank: Super Contributor
timestamp: January 28, 2024, 10:51:31 pm
content: Right thought their Intel era, Apple never cared about or went after people making Hackintosh PCs for personal use.Over the years I used several as my main computer, always seeming to build a Hackintosh using some chip that Apple used in the highest-spec iMac six months later: i7-860, i7-4790k, i7-6700k. The Mac Pros never seemed appropriate for my software development tasks -- too focussed on crazy GPU and I/O for video editors -- and the iMac also doesn't suit me because I like to buy a good monitor and use it on several generations of computer, not expensively replace it every time I change CPUs. Also I was using an Apple 30" (2560x1600) monitor for many years, and more recently 32" 4K monitors, and iMacs have never gone that large.That's all gone now, as no one else makes Arm CPUs as fast as Apple's. Now people are buying Macs to run Linux on -- and Apple doesn't care about that either, and even has actively done some things in the boot process to make it easier.I've never used Basilisk II, but I use SheepShaver to run my 1991 (68k) "Best Books" accounting program when I need to make an invoice. And other stuff. OS X 10.6.8 is a kind of ideal version to run old stuff on as it's a pretty modern OS X but can still run 68k software. It's so great you can run SheepShaver on Mac, Linux, Windows as you wish.I had a Mac II as my work computer when they came out in 1987. Awesome machine at the time, and a huge step up from the Mac Plus. Several years later a IIcx was my first personally-owned computer when (not NZPO type approved) 2400 bps modems became affordable and one of my local BBSs started offering first internet mail and news via uucp and then an actual IP connection (modem into their Sun box and run trn or whatever), and then later SLIP then PPP. That IIcx got a Radius Rocket 68040 card later in its life, before being replaced by a PowerPC 6100AV, then an 8500/120 which had a number of CPU upgrades, to 180 MHz 604e, then 266 and I think 400 MHz G3.

author: Halcyon
author_rank: Unknown
timestamp: January 28, 2024, 11:45:02 pm
content: Quote from: SiliconWizard on January 28, 2024, 09:27:50 pmGreat resource! I actually just came across this site the other day when I was looking for something else.

author: helius
author_rank: Super Contributor
timestamp: February 04, 2024, 08:20:13 pm
content: The first issue of the Mac II had ROMs with a bug affecting bus-master NuBus boards. Later issues have fewer chips (several bus transceivers were combined into a "NuChip" ASIC) and included a footprint for a ROM SIMM instead of the existing DIP sockets. There are newly-manufactured Flash ROM SIMMs that thereby can be used.It's hard to find larger memory SIMMs that work with the Mac II and IIx because they are not compatible with the refresh modes of 4Mbit DRAM chips. A 4 MB SIMM made for these computers must have a PAL on it to swizzle the clocks and enable pins.The Mac II is also one of few computers made that uses the 68851 memory management unit. This chip was not installed by default, as Macintosh System 4 through 6 does not provide virtual memory. Rather a "dummy" PAL in a PGA package called the "HMMU" was installed in the socket meant for the 68851. The real 68851 was required to run A/UX.A Mac LC also has a 68020 (without MMU) and can use Ethernet PDS cards. Many of the PDS cards also have a socket for a FPU. But that is a 1991 era machine rather than 1987. Their performance (if the II had a basic video card like the "Toby") is about the same.I would expect most any 37-year old computer to need some work. Apart from the usual maintenance and repairs the Mac II suffers from its SMD capacitors leaking and the damage from this can be pretty bad. It is slightly less dire than the succeeding models with Maxell lithium cells—the Mac II had soldered lithium cells from Varta that are less prone to explode.

author: brucehoult
author_rank: Super Contributor
timestamp: February 05, 2024, 01:28:06 am
content: Quote from: helius on February 04, 2024, 08:20:13 pmNo, quite noticeably slower, since the LC uses a 16 bit bus. Even worse than the Mac IIsi, introduced at the same time, which also IIRC had a 16 bit bus but at least had a 68030 with 256 bytes of L1 data cache -- and 4 more MHz.

author: helius
author_rank: Super Contributor
timestamp: February 09, 2024, 12:20:13 am
content: The IIsi has a 32-bit data bus, same as all of the Mac II computers. This is clearly the case since they all require SIMMs in identical sets of 4. The LC and LC II on the other hand, only have 2 SIMM slots. You can also verify this by looking at their schematics.The performance difference is less than you would expect. Partially, I think, because a 68020 with no cache is doing a lot of 16-bit bus cycles, as that was the most common operand size.

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 09, 2024, 02:36:54 am
content: From what I remember, the 68020 has 256 bytes of instruction cache, and no data cache. Which seems confirmed by the Wikipedia article. So, even though that's not much, yes a 32-bit bus will make significant difference even for instruction fetching. And of course, there's the data access in any case, which can also be a bottleneck, especially on those systems, we're talking about just a few MHz.The 68030 also has 256 bytes of instruction cache, but it added a data cache that the 68020 didn't have. Again unless my memory and Wikipedia are both wrong, which they may be.

author: macboy
author_rank: Super Contributor
timestamp: February 13, 2024, 12:26:49 am
content: SiliconWizard, you are correct about the caches.I did have an LC, later had an LC II when my brother took the LC with him to uni. I can confirm that the LC II with the extra cache was noticeably faster, but still slow. The 68030 also had a built in MMU and could actually use virtual memory, a real benefit.

author: cosmicray
author_rank: Frequent Contributor
timestamp: February 13, 2024, 01:04:40 am
content: For some reason I want to say that the Mac II did not have an FPU chip (68881 or 68882), but the socket may have been there. A friend of mine got access to the correct FPU and was selling lots of them out of his garage.

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 13, 2024, 01:06:25 am
content: The original Mac II probably didn't (I don't remember and haven't checked), I think it was more for the FX and later ones.

author: brucehoult
author_rank: Super Contributor
timestamp: February 13, 2024, 02:12:05 am
content: Quote from: cosmicray on February 13, 2024, 01:04:40 amThe Mac II absolutely came standard with a 68881 FPU. It didn't come with the 68851 MMU but had a socket for one. It came fitted with a dummy chip (a PLD I think) and a 68851 could be retrofitted.For reference, I had a Mac II at work in 1987, and wrote a lot of FP-intensive programs for it. I later bought a IIcx for home, then added an LC as a "guest computer" replacing a Mac XL which I'd bought used, very cheap. Later I had a Quadra 700, then a series of PowerPC Macs. Before the Quadra 700 I had a Radius Rocket 68040 accelerator in the IIcx. In laptops, I had a PowerBook 100, then Duo 230, then 266 MHz G3 PDQ (which I still have, as the last machine supporting all of ADB, SCSI, serial. It also has a build in modem and ethernet, and I have a WIFI PC card for it, and floppy and CD drive modules)

author: helius
author_rank: Super Contributor
timestamp: February 13, 2024, 06:15:29 am
content: All Macintosh II machines were sold with a 68881 FPU. I can believe some users wanted to upgrade it to the 68882, which was much faster because it was pipelined. From what I understand, this worked using system software 6.0.1 and later—supporting the IIx, which used a 68882.The only II-series machines sold without a FPU were the IIsi and the IIvi.

author: helius
author_rank: Super Contributor
timestamp: February 13, 2024, 06:24:43 am
content: Quote from: brucehoult on February 13, 2024, 02:12:05 amAlso the last PowerBook with support for Apple's 800KB GCR floppy disks. Useful to keep around for data recovery.There are USB converters for serial, ADB, and SCSI, but their compatibility is not 100%. The situation for 800KB disks is simpler: they are never supported by USB floppy drives. But a flux-reading device can image them.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: February 13, 2024, 08:01:15 pm
content: I just find ebay listings often miss things like the mouse, or ADB cable, or have very high shipping to Canada.

author: cosmicray
author_rank: Frequent Contributor
timestamp: February 13, 2024, 10:18:13 pm
content: Quote from: brucehoult on February 13, 2024, 02:12:05 amIs that the WallStreet G3 (in a black case, with the Apple logo that was upside down when opened) ? I have one off to my right about a meter.

author: brucehoult
author_rank: Super Contributor
timestamp: February 13, 2024, 10:34:55 pm
content: Quote from: cosmicray on February 13, 2024, 10:18:13 pmWallStreet is the model before. Lombard (introduced USB) and Pismo (FireWire) are the models after. All look very similar, but gradually thinner.

author: aeberbach
author_rank: Regular Contributor
timestamp: February 14, 2024, 04:02:52 am
content: A Mac II is fairly obtainable, it isn't the one most people seem to want to collect, which is the IIci/Quadra 700. The IIfx is also popular but so rare few even try to find one. The best bang for buck is probably the LC475/Quadra 605 - it is the fastest stock 68k Mac (I think?) and there seem to be plenty around. Can have a full 68040 and be clocked at 33MHz.68kmla.org is a good resource for finding bits and working out what should work.https://tinkerdifferent.com/is also good.

author: brucehoult
author_rank: Super Contributor
timestamp: February 14, 2024, 05:15:21 am
content: Quote from: aeberbach on February 14, 2024, 04:02:52 amI agree with that, and was thinking about mentioning them before. Or the LC 630 / Quadra 630, which are 33 MHz instead of 25 MHz, have IDE disk instead of SCSI, and the Quadra has an FPU. I think I have one in storage.QuoteThe LC475/Quadra 605 is 25 MHz. Unlike the 630, neither has an FPU. I don't know about overclocking.The fastest 68k would be the Quadra 840AV, at 40 MHz.

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 14, 2024, 05:37:46 am
content: Wasn't the top of the range the Quadra 950 though? Or something like that. Pretty expensive back then, IIRC.

author: brucehoult
author_rank: Super Contributor
timestamp: February 14, 2024, 07:06:39 am
content: Quote from: SiliconWizard on February 14, 2024, 05:37:46 am950 was 33 MHz, it just had a bigger case with more slots and drive bays, up to 256 MB RAM vs 128 MB on the others...

author: SiliconWizard
author_rank: Super Contributor
timestamp: February 14, 2024, 07:32:02 pm
content: Quote from: brucehoult on February 14, 2024, 07:06:39 amAh, right. It wasn't the fastest, oddly. Marketing. But expandability and RAM were still selling points.

author: DiTBho
author_rank: Super Contributor
timestamp: February 14, 2024, 09:41:11 pm
content: Quote from: brucehoult on February 14, 2024, 05:15:21 amThe LC475 can accept a "FULL" 68040 with FPU and MMU, and the PLL on the mobo can be overclocked to 33Mhz.Then both serials on board need retuning, otherwise 9600bps is no longer 9600bps, but the rest of the system is "almost" stable.Umm, somehow "funny", but I wouldn't recommend it for everyday use

author: DiTBho
author_rank: Super Contributor
timestamp: February 14, 2024, 09:42:40 pm
content: The Quadra 605 is *THE BEST* machine for MachTen on MacOS v7.5You can have gcc-v2.95 and a lot of UNIX stuff on it