Nostalgia for the Amiga

When I was young, my father owned a series of Commodore machines, the last one being an Amiga 500.  BASIC was for chumps, and our only other alternative was an assembler and a single misprint-riddled book for it.  We didn’t have the internet, or any local user group/mentoring.  We made the asm stuff work, by which I mean, mostly I stole the results of my older brother’s reverse engineering.

Years later, just before the Java phenomenon reached our little community college, I started learning C++ (officially) and C (from the internet), and some mysteries started falling into place.

• The large blocks of declare statements in assembly were a C struct.
• The weird parts of that struct like next_window: dc.l 0 were spaces for the OS to put a pointer to the next window, creating a singly-linked list of windows on screen.
• The difference between label and #label snapped into sharp relief when I reached Pointer Enlightenment. They were *p and p, respectively. (Somewhat; C doesn’t distinguish between absolute and PC-relative addressing.)
• Loading the label at the start of a block of declare statements into a register before making a library call was passing a pointer to the OS.
• The 68000’s data/address register split wasn’t arbitrary; only address registers could be used with an offset, so the pointer-to-struct went in an address register, for reading fields within the struct.
• That weird WaitForEvent function in the OS library was the core of cooperative multitasking.  The Amiga also had preemptive multitasking, but the time slice was large enough to make the system visibly laggy if a process was uncooperative. Like all of my asm programs.

That experience of simultaneous, two-way enlightenment (asm to C and back) with pointers was incredible, but has also been a once-in-a-lifetime high.  It also gave me a lot of “if-only” feelings.  Had I understood all this stuff back then, I could have done so much more with the Amiga.

(Incidentally, that next-window pointer being in the window structure makes it invasive.  I guess this means my first encounter with invasive lists could have been before Linux was ever released.)

I also felt a sort of awe or magic about the hardware design, that was missing from the PC space.  The Amiga was half computer, half game console internally, with a bunch of custom chips to do really neat graphics. Although it had a limited number of colors in the palette, the co-processor could switch out the palette between scan lines, allowing quite a few colors per screen.  HAM mode [hold-and-modify] could also produce “thousands of colors” out of a 16-color palette, if one could accept some color-fringing artifacts.

We didn’t have a VCR or camcorder (the money was spent on the computer) but apparently, the Amiga was great at video, too.

But it was soon proven to be a dead end.  When RAM gets fast enough, a boring linear RGB framebuffer is the best option, and bitplanes (or HAM mode) turn from “cool hacks” into mere workarounds for the era’s limitations.  The 68000 family wasn’t able to keep up with Intel’s immense fab budget to fling clockspeed with the best of them, and Commodore died before a PowerPC transition could have happened.  And who even knows if they could have been as successful as Apple with it?

The Amiga’s ability to “just plug it into a TV” became a limitation over time, as the business world put all its money into PCs with dedicated monitors.  They were more expensive, but also better.  Our first PC would run in 800⨉600, although it could also produce a flickery 1024⨉768.  By comparison, Workbench on the Amiga ran in “medium” resolution, 640⨉200.  High resolution only doubled the line count, and flickered intensively on our monitor.  Ultimately, monitors came down in price and offered much better than TV quality; I went off to university (post-community-college) with a monitor capable of 1280⨉1024.

This entry was somewhat prompted by “Classical "Single user computers" were a flawed or at least limited ideas”.