A Technical History of Apple's Operating Systems

An anonymous reader writes "As part of his 1680-page book Mac OS X Internals: A Systems Approach, Amit Singh of kernelthread.com wrote a very detailed technical history of Apple's operating systems. Since he had to cut down on the history chapter because of the book's already too-large size, most of this chapter didn't make it to the printed book. Singh has made available the history chapter as a free PDF. The file is 140 pages long, and is generously filled with figures and screenshots. It starts with the internals of the original Apple I and goes through a tour of all operating systems Apple dabbled with, including internals of A/UX, Lisa OS, and such. It even covers details of outside influences like the Xerox Alto, STAR System, Smalltalk, and Sketchpad, and closer to home things like Mach, NeXTStep, and OpenStep."

Comments

That's not Memory Protection

[LKM]

Technically, that's not memory protection, but memory consumption. Memory protection protects the address space of each application from other applications, so applications can't overwrite other application's memory data.

Prior to Mac OS X, all Mac applications shared one common memory space, which had the advantage that hacking was simple, but had the disadvantage that one rogue application could crash everything, or even worse, change other applications' data without anyone noticing.

Re:What I want to know is

[TomHandy]

It's not so much that Apple "decided" to stick with the classic Mac OS for so long despite Win95/98 as much as that they were just in a total mess in terms of their next gen OS stuff. Apple spent a lot of the 90's trying to figure out a new Mac OS, and a lot of the future was supposed to be in the original projects codenamed Copland and Gershwin (the original Mac OS 8 and Mac OS 9...... what eventually came out as Mac OS 8 and Mac OS 9 had little to do with this). Copland was originally supposed to be a totally modern OS, and Gershwin would apparently have had even more radically new elements, a lot borrowed from the Taligent collaboration with IBM on an OS codenamed "Pink". But none of this ever panned out, and all Apple could do was release the commercial Mac OS 8 and Mac OS 9 OS's as stopgaps. Apple had considered buying BeOS once it became clear that the internal Copland project wasn't working out, and they ultimately ended up buying NeXT. For all intents and purposes, Apple became NeXT, and Mac OS X can be seen in many ways as the ultimate development of NextStep, rather than the classic Mac OS.

Re:What I want to know is

[TomHandy]

Actually, looking through the Mac OS X Internals PDF, there's a whole section there about Apple's quest for a new OS........ this goes into a lot of detail about all the options Apple considered. This is actually some great reading if you're curious about all of this.

Re:What I want to know is

[TheRaven64]

The features that MacOS Classic lacked were mainly:

1. Good multi-user support.
2. Pre-emptive multitasking.
3. Protected memory

If you wanted these three, you had two choices; UNIX or Windows NT[1]. Other consumer operating systems didn't have them. Windows gained Pre-emptive multitasking with Windows 95, but it didn't get the other two until MS abandoned 9x in favour of NT. BeOS didn't have the first, but did have the second and was quite popular with Mac users.

What it did have was a heavily Raskin-influenced GUI, which left pretty much anything else in the dust when it came to usability. NeXTStep was in the same area, but much more expensive.

[1] Or VMS and a few others if you had a huge budget.

Re:Those were the days...

[Anonymous Coward]

Too bad you got modded down. gasmonso isn't trying to annoy people with sigs disabled. No, he's abusing Slashdot to try and increase his site's PageRank.

Sigs get the rel="nofollow" attribute added to them, as do all posts. (Check it out: view the source for this link, and see the rel="nofollow" added.) There's one exception: posts posted with the +1 Karma Bonus. Posts made with the Karma Bonus do NOT include rel="nofollow". Go ahead, check out the source of gasmonso's comment: no rel="nofollow" because he posted using the karma bonus.

gasmonso always posts with his not-a-sig at the bottom to enable him to spam Google with that link.

(To check the source, I'd highly recommend using Firefox and it's "View Selection Source" feature. Just select the text around the link, right click, and hit "View Selection Source". Then check for rel="nofollow".)

So the "fuck you" is totally appropriate, although not just for people who have disabled sigs. gasmonso's acting like a spammer, trying to leach of Slsahdot's PageRank.

Re:I did

[revscat]

If you haven't done so already, you may want to check out Quicksilver. It's technically an app-launcher, but it has by-and-large replaced Finder for me. You can use it for all your file operations: open, move, unmount/eject, move to Trash, etc.

Re:Singh is an idiot - so many errors

[inaddrany]

Why is the parent poster getting modded up as informative? I'd trust Amit over what appears to be an obvious troll. I'd also trust the 6500 spec sheet and the original Apple manual that I managed to dig up.

For example, it says in the Spec sheet "Addressable memory range of up to 65K bytes", "On-the-chip clock options: Crystal time base input", etc:

6500 data sheet

"Microprocessor Clock Frequency: 1.023 MHz"

Apple I Manual

etc.

Re:Singh is an idiot - so many errors

[Ancient_Hacker]

Singh may be really good at the newer stuff, but the old stuff he obviously did NOT dig into the hardware or software first hand. There ARE LOTS of of errors, half-truths, and very important omissions in this chapter! Let's list a few:

• The 6502 had an alleged crystal-control capability, but in every 6502 board I've seen (almost a dozen), every one of them uses a separate clock oscillator.
• You can only get 16 addressing "modes" if you count each register as a different mode. And the indirect Y mode I don't think anybody ever found a use for. More like 6 usable modes.
• Dunno where he got the 65 cycles reserved for refresh stuff. The CPU had no refresh mode built in.
• The Apple ][ came with a DC power cord?
• The Lisa could not have a on-chip MMU, as there was no MMU available for the original 68000.
• The discussion of memory management on the Lisa is all wrong. The Lisa used a 68000 CPU, which had a major flaw-- memory faults were not restartable, plus there was no virtual memory management unit on the CPU or available. SO virtual memory was extremely constrained:: Apple had to design their own (slow and very limited) MMU, AND page faults were completely disallowed! A program had to obey a certain page-touching protocol to succesfully run. All stack expansion had to be first pre-flighted by touching a lower stack location, otherwise the system would hang. Not a pretty state of affairs.
• The writer obviously has never tried using or programming the Lisa Office System. Some tidbits:
  • It took about 30 seconds for the calculator to pop up. Then when you typed "1+2", it took about another 30 seconds of disk-whirring for the system to load the SANE numeric library and cough up "3".
  • Any system API call took nearly forever. You dared not poll for input very often as that would chew up a lot of time and slow down the whole system. But you couldnt try polling every so often, because just the call to get the system tick count took forever. Catch-22 ala big-time.
• The UCSD p-system was not command-line driven, it used top-line menus and single keystrokes.
• The UCSD editor was "modal", as it did have insert nad delete moes, but perhaps more importantly it was perhaps the first FULL SCREEN EDITOR accessible to the masses. Speedy too, as long as your file would fit in RAM.
• The Mac did not have a four-voice audio synthesizer. there was only one 8-bit audio D/A. Any multiple voicing had to be faked in software.
• Very cursory and obviously second-hand discussion of the Mac Toolbox API's. Not a mention of the revolutionary concepts introduced, such as the memory manager, memory ptrs, memory handles, resource forks, system hooks, drivers, etc...
• Multifinder was an outgrowth of Andy Hertzfield's "Switcher", and very very slick for a cooperative multitasking non-memory protectred system enhancement.
• Opinions may differ, but to many many people, System 7 was in no way a gigantic leap forward. Some of its "features":
  • Roughly a doubling of the basic API's, all of them implemented as RAM-hungry patches.
  • A Color QuickDraw, which was SEVENTEEN times slower at drawing text than the previous QuickDraw in ROM. Andy Hertzfeld eventually released a recoding of this to speed it up considerably.
  • A completely redone and completely unusable sound management API.
  • A basically unsable virtual memory system, trying to squeeze memory through a slow 8-bit SCSI port.
  • Proprietary "publish" and "subscribe" info sharing API's, which nobody ever used.
  • A rewritten Finder, with many many faked features, such as font and system resources presented as fake folders of "files".
  • Poor support for TCP/IP, threading. No support for SLIP or PPP.
  • A completely redone networking stack, based on all new, slow, and lousy code.
  • Much higher memory usage, very slow in places.
  • Many of us stayed with system 6 as long as possible, even Apple re