For years, I’ve heard it said here and there that the first Macintosh operating system, called System 1, was written in a version of the Pascal programming language. Ken Gregg wrote a nice Quora answer that definitively answers whether this is true: Yes, partially. Parts were written in a customized version of Pascal that allowed “unsafe” operations, but most of the OS was written in 68000 assembly language, due to memory constraints.
This article from Folklore.org hints that a larger portion of the Lisa’s operating system was written in Pascal. Some of the Mac’s system software was ported from the Lisa (mostly translated to assembly).
Ken said the first programming language to run on the 128K Mac itself (rather than on the Lisa dev. system) was MacForth, by Creative Solutions.
The Lisa development system for the Mac offered two options for writing application software: Pascal, and 68000 assembly.
I read the referenced sources. Thank you for the pointers! Andy Hertzfeld’s writings at Folklore.org offer great insights into the early days at Apple.
But I would opine that not a shred of Pascal code was delivered in the first Macintosh OS—there was simply no room. I managed to trash pick an old Mac Plus, a luxury model compared to the original 128k Mac. On a single (probably 800k) floppy that came with it, someone fit Microsoft Excel 1.0, the complete OS, and there was enough space left over to store your spreadsheet files.
P.S. Apple’s original goal was to ship the first Mac with only 64k of RAM. That’s the memory configuration the team engineered their software for. But with the video buffer, bitmapped fonts, the window system, etc., 64k just wasn’t enough.
Hmm. Gosh, I never heard of a 64K configuration being considered.
The floppies on the 128K Mac held 400K per disk.
I remember Steve Jobs saying that the original System 1 OS was 24K. My guess is there was about 21K set aside for screen memory (assuming 8 pixels per byte). So, there was a little over 82K left for program and data memory.
Mark Barton, the creator of the Mac’s (and Commodore Amiga’s) speech synthesizer, “MacinTalk,” talked a bit about a plot complication in the movie “Steve Jobs”, where, “there isn’t enough memory for the Mac to say ‘hello’.” He said that was only partly true. It was true there was a memory problem with the demo for the unveiling, but it wasn’t the speech synthesizer that was the problem. It was the amount of bitmap graphics that was needed for the demo. In order to do the slideshow part of the presentation, the Mac had to load all of the images into memory at once, and there wasn’t enough on a 128K Mac to do that. So, unbeknownst to the audience, they used a 512K Fat Mac to do the demo, a configuration that wouldn’t be released until a year later.
The original Mac prototype used a 6809 processor and 64KB of memory. The screen resolution was smaller than later versions. The group got excited with the 68000 used in the Lisa but Jef Raskin claimed going to 16 bit memory would mean 128KB and that would make the machine twice as expensive even if the price different in the processors themselves was not as dramatic. So Burrell Smith replaced the 6809 with a 68000 and a simple circuit to give it an 8 bit bus (I am just guessing here, but I would expect this to be more like what the Acorn Electron did than what the 68008 tried) while keeping the rest of the prototype as it was, including the 64KB of RAM. This got Jef to relent and the Mac group was now able to share software with the Lisa. The next prototype just increased memory to 128KB and made things simpler. I don’t know if that was before or after Jobs took over the project.
Wikipedia says the Fat Mac was launched on September 10, 1984. For some reason I remembered July of that year as the date. Perhaps that was when they launched the external floppy making it a bit less awkward to use the original machine.
Interesting. So, it started out as an 8-bit design, using the same processor as the Radio Shack Color Computer.
Another little note I remember is that one of the prototypes (the 16-bit one, it turns out) used the same “Twiggy” drive as on the Lisa. As I’ve imagined, it had a cyclopic wry “grin.”
Thankfully, they decided to ditch that for the more reliable 3-1/2" drive. Twiggy drives were notoriously unreliable, so I hear. Plus, they used a proprietary disk configuration, with a read/write head both in front and toward the rear of the drive, with disks that had “windows” on the top and the bottom of the jacket. You had to be careful where you put your fingers.
I agree the 3 1/2” floppy (with Sony drive) was an improvement in usability, but the 5 1/4” media was more archival. I still have some that still work flawlessly, whereas our protocol in the late 90’s was to make a backup copy of every incoming 3 1/2” software distribution disk because they failed so often. I assume this is because the bits were physically smaller.