Using a disk drive today is trivial. But back “in the day,” it was fairly complex both because the drives were simple and the CPUs were not powerful by today’s standards. [Thomas] has been working on a 68000 Mac emulator and found that low-level floppy information was scattered in different places. So he’s gathered it all for us in one place.
Low-level disk access has a lot of subtle details. For example, the Mac calibrates its speed control on boot. If your emulated drive just sets the correct speed and doesn’t respond to changes during calibration, the system will detect that as an error. Other details about spinning disks include the fact that inner tracks are shorter than outer track and may require denser recordings. Laying out sectors can also be tricky since you will lose performance if you, for example, read sector one and then miss sector two and have to wait for it to come back around. Disk sectors are often staggered for this reason.
Adding to the complexity is the controller — the IWM or Integrated Woz Machine — which has an odd scheme for memory mapping I/O. You should only access the odd bytes of the memory-mapped I/O. The details are all in the post.
In a way, we don’t miss these days, but in other ways, we do. It wasn’t that long ago that floppies were king. Now it is a race to preserve the data on them while you still can.
Floppy Disk
Froppy disk. (It was made by Sony.)
Furoppi disuku to be precise. XD
I had one of the early 128k Macs. I still remember the floppy swapping fun that entailed. But the system was so super cool (for the time)… And portable, too! (I would put it into a carry bag to tote it around.)
I believe you, even though a Mac 128k may have been a little before my time.
Please tell me, what was it like having a Macintosh when an acquaintance or your friends had a TRS-80, ZX81/Timex 1000 or a C64 and had to struggle with it?
Didn’t it feel a little unreal? The whole situation, I mean. You had a Mac with a GUI and networking capabilities while the others were still rewinding their cassette tapes and typing in Basic listings from homecomputer magazines? That must have felt like stoneage by comparison, right?
It was awesome! I had a 128k (I’m pretty sure) with 2 floppy drives (a lot less disc swapping!) at home as a kid thanks to my dad bringing one home from work.
Friends if they had anything had an early games console, or a BBC. School had BBCs with floppy discs.
Later had an SE/30 with a 40Mb HD and 5Mb RAM! By that time, friends had Amiga, Atari, or XTs. But the Mac had real serious software which you could actually do proper stuff on like draft homework.
It was an awesome bit of kit. GUI, HyperCard, and appletalk. Mouse! Keyboard with a backspace key!!!!
Games were good, though very different, due to the B&W screen and being more aimed at adults.
Great memoris! Thank you for your sharing your experience! 😃
Looking back I think that “Glider”, the game with the paper plane caught my true attention for the Mac first time.
I knew about Glider because it existed on Windows 3, too.
Myst was also a game being popular for being available on both Windows and Mac. But that was in the 90s already.
Glider is available for Android, too, now, with all the original levels. It’s got some other name, because of the license restrictions on the levels.
lol; mostly competed with PC at that time, where folks also had floppies and also a vastly larger software market. Those other machines had floppies, and also color displays.
Networking was yet to be game-changing because we had no networks to speak of beyond BBS, etc. Networking was used in a LAN context, where it was great to have if you needed it., but to need it meant you had a lot of hardware which was $$$ and so home users were rarely in a position to have such a need.
At that time I was in college, and we had a ‘Mac Lab’ which was used for the work processing. The networking was handy to connect to the shared laser printer. That was the first time I used a mouse and it took me a little practice. WYSIWYG editing was cool.
But the other machines were much more hacker and developer-friendly, much cheaper, with a greater software market base, and so Mac ever-increasingly became a niche machine.}
But it was cute to look at.
Folks were religious about their computer allegiances, and there were bar brawls.
“But the other machines were much more hacker and developer-friendly, much cheaper, with a greater software market base, and so Mac ever-increasingly became a niche machine.}
But it was cute to look at.
Folks were religious about their computer allegiances, and there were bar brawls.”
I see. So we could say 8-Bit machines like Apple II, TRS-80 and Atari 800 were poorer at being general-purpose computers or “PCs” (doing homework, painting, word processing), but could be more easily be used for electronic homebrew projects? Like reading a photodiode or NTC?
Yes.
It’s anachronistic to think anyone was winding cassette tapes in the time that Mac came out. It’s also anachronistic to think anyone with a Mac was networking when it came out in ’84.
As for the 8-bitters not being general purpose, recall that generation is where Visicalc was born, the mother of all things we call spreadsheets. That is where WordStar was born (and several other word processing ‘programs’ (we didn’t call them ‘apps’ then)). It is also where graphics such as SubLogic’s FS1 was born, which eventually was acquired by Micro Soft (the older name of the company), it’s legacy living to this day in the form of MS Flight Simulator. It’s also where the computer algebra system Mu Math was born (by Soft Warehouse, and retailed by Micro Soft, though not acquired). Frankly, upon reflection, it’s quite remarkable what was able to be done on 8-bit processors with a 64 KiB address space and a paltry 89 KiB floppy disk. I’m not sure what “doing homework” entails, but I will concede that “painting” would probably be a stretch for those old machines.
But no, I don’t think the 8-bit folks were jealous or in awe of the Mac when it came out simply because they had already long since moved on to then-contemporary technology. They had either become mac people themselves, or (just statistically more likely) became pc people.
Technology obsolesced very fast then — very much faster than now. It was ruinously expensive to keep up.
74-84 was about market development of ordinary individuals contemplating wanting a ‘home computer’
84-94 was about graphics, memory, storage, local networking, and the use of PLLs to get magnitude orders of CPU speed increases
94-04 was about global networking, with incremental improvements in the other
04-14 was about resurrecting a 60’s concept of metered computing, in what we now brand ‘cloud’. Also, mobile gets big, as does massively parallel compute in GPGPU
14-24 seems more of incremental improvements, but AI and ML are the new hotness
We’ll see what the next decade brings, though I don’t think anyone will meaningfully reflect back on my 24 core processor and RTX 4090. They’re just tools in their time, and will obsolesce soon enough like all the others.
[ziggurat29]
That was a nice condensation of personal computing history you did there!
(Clapping hands)
I went from a TRS-80 Model II to a Mac 128K. I had no networking other than BBS access with a 300 baud modem. It was all very cool at the time. By about 1990, I abandoned Apple in favor of the PC platform. Last Apple computer I had was the Mac Classic.
I still have my Mac 128K brochures and a copy of Byte magazine with every advertisement page containing something from Apple.
The nice thing about owning a C64 over a Mac 128K is you had enough money left over to also own a car. ;-)
But not really. Mac’s contemporaries were expensive too.
A year later, and one could get a much higher spec (256K) Amiga 1000 for a little less than a Mac 128K. And it has the pedigree of being a good game machine like the C64 was. This was the machine I always coveted back then, not the Mac.
The IBM PC/AT cost about twice what a 128K did back then, the 286 was better on paper but worse in practice than a 68000 with no MMU. But you could hook a printer up to a PC and even a network interface. So the PC was still a very capable machine for business, even if CGA and EGA were not used as effectively as Macintosh’s monochrome framebuffer.
The prices dropped really fast on the IBM and the clones, and the 8088 PC’s were pretty well established by the time the Macintosh arrived in 1984. Which is why IBM-compatible makers “won” even though the software for it was generally less polished. Most would not have guessed this victory, because back then the “IBM-compatibles” were unable to run a pretty significant fraction of the software for IBM PC. (perhaps 5-20%?)
That’s not really the correct reason why the IBM PC ‘won’. In 1984 it was already possible to see that the PC was going to dominate the entire industry, even before price competitiveness, nor clones, because there were almost no clones at the time and the only useful models were the original 5150 PC and the XT (which supported hard disks in its BIOS ROM) and both were expensive.
The PC was neither the cheapest, nor the fastest, nor the most capable microcomputer of the day. The term ‘PC’ wasn’t even novel, because many computers were called Personal Computers at the time. For example, the biggest-selling British computer magazine at the time was called “Personal Computer World” and had been published monthly since 1978.
The reality is that the PC ‘won’, because it was a safe decision for managers to buy it – “nobody ever got fired for buying IBM”. IBM was big and its PC provided market confidence.
“The IBM PC/AT cost about twice what a 128K did back then, the 286 was better on paper but worse in practice than a 68000 with no MMU. But you could hook a printer up to a PC and even a network interface. So the PC was still a very capable machine for business, even if CGA and EGA were not used as effectively as Macintosh’s monochrome framebuffer.”
Speaking of PC/AT vs Mac, I wonder why there never had been an Mac emulator for PC or PC/AT way back in the 1980s.
I mean, both Amiga and Atari ST could boot Mac’s ‘System’ through use of an emulator.
Okay, the PC/AT was 80286 based and didn’t have an Motorola 68000 on-board like the other two systems did, but an 68000 on an ISA card was an possibilty.
In reverse, that’s what PC emulators did on Atari ST and Amiga, they often had an NEC V30 on a card.
And Hercules graphics on PC had higher resolution than Macintosh. That’s 720×348 vs 512×342.
Memory was no issue, either. PCs had 512 or 640KB of RAM, sometimes Expanded Memory, as well.
So emulation of a Mac 128K might have been possible?
No, emulation of an 8 MHz 68000 on a 6-12 MHz 80286 would be far too slow. The Mac “emulators” for the ST (MagicSac and Spectre) did not emulate a Mac at all. Instead, they patched the original 68k Mac ROMs (from a Mac 128/512k or Plus) and replaced the Mac-specific drivers with drivers for the peripherals in the ST – including support for the increased resolution of the monochrome SM124 screen (640×400 instead of 512×342). The 68000 CPU then executed the (patched) ROM and applications natively.
Fun fact – modern 68k Mac emulators such as Basilisk II and Mini vMac still work in the same way. There’s no emulation of components such as the IWM floppy controller, instead the drivers are exchanged for code that executes something like hypercalls to the underlying emulator (but the 68k CPU is emulated if required).
There was in fact an ISA card that supplied a 68000 CPU to overcome the performance problems, the Janus. I could only find an old German article:
https://www.stcarchiv.de/stc1994/11/janus-atari-emulator
Yeah, if you had the money for a Mac, it was often a better computer than anything else at that price. But they were expensive (for kids) in the sense that you couldn’t get /any/ kind of Mac for $200, and no one had a hand-me-down because people weren’t throwing them out.
Not much has changed in 40 years; you still see certain folks pouncing on Mac-related comment threads to explain how a $2,000 Mac is overpriced by comparing it to what would be a $3,000 PC build. Because exclusivity can really rub people the wrong way, regardless of actual numbers.
From my memory of that era:
The original Macintosh appeared in 1984. It didn’t really compete with the home computer market, but the business market, because it was so expensive. It briefly met sales expectations (of about 10K sales per month), but by the end of 1984 sales had fallen behind and Apple were mostly relying on Apple ][ sales (Apple //e and //c) for their income.
The C64 had appeared in 1983, so had only been around for a year, though it was already very popular, with 1.7m sales. Then there was the ZX Spectrum, with about 1 million sales by the announcement of the Mac; followed by the VIC-20, the ZX81/TS1000 and an assortment of BBC Micro/ Tandy CoCo/ PET/ Oric/ etc.
The higher end of the market was dominated by the Apple ][ range; CP/M business computers (very much like the PC clone market, but 8-bit); the IBM PC (which was still <50% by then, but probably above 25%); Victor/Sirius MS-DOS computers etc. These all had disk drives, and a non-GUI (mostly Text graphics) interface. There were also a few business 32-bit, 68000-based computers appearing around the same time as the Mac, such as the Sinclair QL (pre-announced Jan 1984) or the Sage ||.
This meant that less than 0.1% of users experienced one in the early years. Furthermore, our computers didn’t seem primitive at the time, because we worked within their limitations and because they were stunningly powerful devices compared with anything almost anyone had access to before the 1980s.
So, everything we understood about the Mac was derived from reviews of the computer in early 1984. It certainly seemed to be like a highly futuristic computer though, and getting your head around the concepts was challenging. For example, because no programs could ever select anything on a screen using a pointing device it was kinda impossible to imagine what point-and-click software would be like. Software at the time always worked as a hierarchy of keyboard-selected options which would then lead to some kind of text entry; or maybe like a video game where each individual key generated a global action (perhaps Ctrl-Keys in business programs); or you were entering data on a ‘Form’ where fields were hi-lighted in reverse video and you pressed to go to the next field.
There was a surprising amount of criticism of mice, on the grounds that they’d be inefficient by taking your hands away from the keyboard. The futurism of the Mac was moderated though because Apple had already released the Apple Lisa about 6 months earlier, and it had a higher horizontal resolution screen.
The limitations of the Mac were also widely reported: 128kB was seen to be inadequate; people were surprised Apple didn’t make it PC compatible; the small screen was noted (even the 8-bit BBC micro could do better); the lack of disk drives (and the resultant disk swapping); the lack of third-party applications; the effort required to write apps; the lack of expansion; the lack of hard disk.
So, in many ways it had a mixed reaction, more like a futuristic technology demonstrator than a computer to compete with existing models. Nevertheless I remember being excited by it and in my ‘O’ level Computer Studies project in 1984 I attempted to make my program Icon-driven (the program placed graphical icons at the bottom of the screen which you had to use to select its major functions). It was only in 1986 I got to use a Mac (Mac 512) for the first time and really began to understand the revolution it represented. Even then, I didn’t own one until my Sinclair QL became too limiting in 1993: the Performa 400 I bought still works perfectly, 31 years later! Note: I’m typing this on a Mac mini 2012.
Hope this helps.
Mice are still inefficient because they move your hands from the keyboard.
I am addicted to Lenovo TrackPoint especially for spreadsheets and word processing.
I have tried an HP Elitebook track nub as well. It’s good, but oddly it’s missing the middle button for scrolling, which seems like a huge oversight (or it’s under patent? But I doubt that.)
In an odd twist we are moving farther from logical inputs when getting work done because people are now demanding touchscreens.
Does anybody remember the trackball? The big, stationary model on the desktop?
I think it had been popular for a brief moment.. Late 80s to early 90s? 🤔
I still haven’t gotten used to the trackpoint on my ThinkPad.
There is an wealth of stories about the development of the Macintosh over at folklore.org including a few about the disk drive setup. This article made me think of how the team went behind Steve Jobs’ back and sourced the floppy drive from Sony because they disagreed that they could develop it internally in time to ship: https://folklore.org/Hide_Under_This_Desk.html
Staggering the sectors was known as “interleave factor”, and I didn’t realize floppies did it too, having only encountered it in the context of PC hard drives in the MFM/RLL era. Many machines weren’t fast enough to keep up with a 1:1 interleave, so you’d go 2:1 or even 3:1 to be on the safe side.
super common. e.g. TRSDOS had an interleave of I think 3. floppy IO was often polled, not interrupt or dma, and you needed give the CPU some time after loading a sector to do something with it before requesting the next one. sad if yo have to wait a disk rev to get it.
When I first went into business consultancy this was my ‘portable’ that went with me everywhere! It certainly was practical compared to some of the larger ‘suitcase style’ PC variants and the software was much more useable and it was reliable.
^^^ is one of the most interesting comments I’ve read on the original Mac recently. The mid-1980s were indeed the “luggable” computer era and I always thought Apple were awfully late to the laptop market (with the exception of the DynaMac and Outbound, but they were repackaged Compact Macs).
But of course, the compact Macs would have made decent luggable Macs, because they were designed to be carried, with the handle on the top (and in the case of the earliest Macs the availability of a bag with a shoulder strap).
Thanks for that!
Sorry, I accidentally reported Joshua’s comment about the trackball.
I really wish there was a No I Didn’t Mean It button for the Report.
I meant to reply: I use a trackball every day, it’s my preferred pointer device, even better than the trackpoint on my ThinkPad.
I had a lot of computers in that era. The real comparison I think was the mac and the C64 for me. The mac came with a floppy drive, a big plus, but you could only have one, and it had zero room for expansion. The C64 had color and sound, and room for expansion. It was more of a toy machine but I think that was more marketing than anything else. I had my 64 for at least 10 years and never had an issue with it. The early macs had the cap and inductor that would catch on fire, they had the glue that would get under where the connector was, and the lubricant in the floppy drives would turn to tar and they would not eject properly. We had pee cees at work so I got me a 286 and that was fun and within a year or two I got my first Sun 3. I had a lot of Sun 3 stuff. I really liked it. I had a bunch of sparc stuff too up until I downloaded the images of two oddly formatted floppies and a buddy told me to give it a shot on my new 386. That was linux, and it was pretty base but it grew fast, and took over a lot of things. I still miss my old two headed Sun 3/60 though. One color head and the other the extra high res mono, 24 wopping gigs of ram… And even a telebit trailblazer, the first gen, they were a bit of a riot. They refused to give up and a lot of the time if one side hung up, the other side would keep on trying for hours. They re vamped the roms so they could negotiate a hang up.