Operating system vendors face this problem once or twice a decade: They need to migrate their user base from their old operating system to their very different new one, or they need to switch from one CPU architecture to another one, and they want to enable users to run old applications unmodified, and help developers port their applications to the new OS. Let us look at how this has been done in the last 3 decades, looking at DOS/Windows, Macintosh, Amiga and Palm.
The heritage of different operating systems has been discussed many times. Mac OS X includes code from Mach and BSD, AmigaOS is based on TRIPOS, MS-DOS is a CP/M-86 clone and Windows NT is modeled after VMS. But what machines and operating systems were used for cross-compilation and bringup of these systems? In order to find this out about Mac OS X, I talked to a few people working at NEXT and Apple, and people that worked on Mach and BSD.
Every touristy place has them: Souvenirs with given names on them. If you have an uncommon name, or a friend with an uncommon name, you might look through the whole collection – and notice that they have generic ones like “#1 FRIEND” (i case you really don’t find your friend’s name), and, sometimes, generic ones in Spanish.
My last blog post showed the Zuse Z3 (1939-1941), the world’s first working digital Turing-complete computer. Let’s go back two more steps: The Zuse Z1 (1936-1938) shared its design with the Z3: It read its program from punched film and used floating point as its internal representation of numbers. But since it was all mechanical, it never worked reliably.
This article is in German, since it is about the German TV show “Supergrips” and how the scoreboard was implemented.
Here are all three volumes of the original 1985 edition of Inside Macintosh as a searchable PDF:
I converted the first issue of the German Commodore 64 magazine 64’er into a searchable PDF:
If you disassemble any version of Microsoft BASIC for 6502, you’ll find this code in a function that normalizes the (simulated) floating point accumulator:
If you type “WAIT6502,1” into a Commodore PET with BASIC V2 (1979), it will show the string “MICROSOFT!” at the top left corner of the screen. Legend has it Bill Gates himself inserted this easter egg “after he had had an argument with Commodore founder Jack Tramiel”, “just in case Commodore ever tried to claim that the code wasn’t from Microsoft”.