Thursday, April 22, 2010

Expanded Amiga 500, Death of a Friend

The Amiga 500 is a 68000 machine, with all of the limits that implies.  I had expanded mine several times over - the 512KB expansion/clock option was nice, and the extra 4MB Fast RAM was even nicer.  Adding the hard disk made the machine much more usable, and I was starting to do some video capture with my DCTV box.    On my job I was working with VAX's and MIPs R3000 based boxes, and the A500 was starting to feel a little sluggish in comparison.  Memory was getting tight too, as I was running UUCP in the background and processing a fair number of Usenet newsgroups nightly, thanks to a connection through a friend at Digital Equipment Corporation to the Internet, and later through Portal (!gdc!aminet). I eventually found what I wanted from a company near Dallas called Microbotics.
Microbotics made a 68030 based accelerator for the A500 called the VXL-30.  This card had various options (see link), but mine was a 68EC030 clocked at 40Mhz with the 68882 math co-processor.  The board fit into the motherboard's CPU socket, and you placed the original 68000 on the board to allow the machine to fall back to "stock" speeds for some games and other non-030 friendly software.  By this time my A500 was up to Workbench 2.04 standards, and the original (or OCS) Agnus chip was replaced with the upgraded "Fat Agnus" chip, allowing a full 1MB of Chip RAM.
I was also in the process of moving from Ohio to Texas, and I fortuitously found myself near the Microbotics facility.  This was great, since my board was an early board and needed some changes to accept the new RAM-32 card which provided 32-bit RAM for the accelerator board.  Since the board sit into the original CPU slot (the A500's expansion options were limited after all), all memory access had to be made to the original 16-bit bus also.  This put a serious crimp on the speed of the 68030 when it needed to access memory.  The solution was 32-bit RAM, and I wanted it badly.  So badly I walked into the front door of the company and sat in the parking lot while the engineers modded my board to accept the RAM card.  And I maxed it out: 8MB of glorious 32-bit ZIP memory.
The performance increase was great - I was now rendering ray-traces faster than the MIPs box at work, and disk transfers just flew.  The Amiga 500 transformation was complete, from stock A500 to the A500 muscle car, chopped and lowered with a blower.
But, to use technology and science fiction writer Jerry Pournelle's favorite phrase, "Alas" it wasn't to be a long honeymoon.  After leaving Dallas my next port of call was going to be Tulsa Oklahoma, via a side trip back east.  And, the company said, I needed to be there yesterday.  This meant I wasn't going to be packing my machines up lovingly, and I would have to fly out leaving them behind.  The packing would be done later by the shipping company.  They did a reasonable job, except that they did not secure the card in the machine, which broke loose from its socket and scrambled itself and the motherboard.  The A500 was dead.
It was early 1993, and the Amiga scene in the US was starting to dim - Commodore had not done a good job marketing the machines nor in upgrading the special technology that made the original Amiga's special.  I decided it was time to transition to the PC world.  With the help of a nice insurance settlement for the Amiga, and the sale of the remains of the A500 (for parts mostly, tho I suspect that the gentleman who bought the accelerator card should have been able to revive it with effort), I moved to an Intel '486DX 33Mhz (12MB RAM) with a VLB SVGA video card and a Soundblaster.

Next: Revisiting that "accelerated" through emulation
Later: "New" Amiga hardware!

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