brainsnorkel.com

Manifesto-driven development. Eclectic thoughts.
  • rss
  • Home
  • Tech
    • Getting wireless WPA-PSK working under Ubuntu Linux on a Dell Inspiron with Netgear WG511
    • Troubleshooting
      • iTunes freezes up randomly
      • Add media buttons missing from WordPress?
    • VoIP + Networks
      • Installation
      • FreeBSD box
      • Router
      • OzTell
      • Configuration
      • Requirements
      • Sipura SPA-3000
      • References
      • Using Asterisk
      • WRT54GP2 and iiNet VoIP
  • Development
  • Writing
    • Australian Republic
      • Chapter I - Introduction
      • Chapter II - Historical Background to Australian Republicansim
      • Chapter III - Republicanism as a Political Issue in Modern Australia
      • Chapter IV - Multiculturalism as a Basis for Republicanism
      • Chapter V - Conclusion
      • End Notes and Bibliography
    • Miscellaneous Pages
      • Requirements Matrix: Julian vs Flickr
  • Games
    • Follower
    • myphatlewt.sh
    • Flash Asteroids (for IE)
  • About

Fossilized Amiga bones

24-Aug-2008

I was foraging around in some old boxes when I found a small collection of things that used to be in Amigas I have owned.

Here’s what might be the original Motorola 68000 processor from my Amiga 1000:

Motorola 68000 processor

I believe this might be the processor I swapped out for a 68010 in a vain early attempt at a speed upgrade (the Amiga 1000 was architected to be synchronous with PAL and NTSC video frequencies so overclocking wasn’t even a dream back in the day).

I recall severing one of the pins during some overenthusiastic and too-frequent brain transplanting, but the one you see above is bent up a bit yet doesn’t have any missing pins. It’s in better condition than my own brain’s recollection of where this processor came from, it seems.

The 68010 was mostly indistinguishable in performance from the 68000 and screwed up many of the games of the day, possibly because of their reliance on the 68000’s loop speed as a precision timing mechanism. I used to pop it in and out while I was searching for the 68010 emperor’s new clothes.

Eventually the 68000 and 68010 gave way to a 16MHz 68020 & 68881 LUCAS board, which provided excellent bang per buck in terms of performance and ram upgrades, and allowed the 68000 to be switched back in for games compatibility.

This is the “Agnus” chip from either my Amiga 2000 or someone else’s Amiga 500:

Commodore Amiga "Agnus" 8371 chip

This was the chip responsible for most of the bling in typical Amiga graphics demos. It contains a hardware blitter, video coprocessor, DMA controller, and a bunch of other functionality. I can’t recall the fault, but I can recall that replacing it made life a little better.

I believe this is the Intel 8088 (actually made by Siemens) that occupied the strange little expansion box called an Amiga Sidecar:

Intel 8088

The Amiga Sidecar was an IBM PC clone in a box that, as you can tell from the Wikimedia image, did not make the Amiga any prettier, but it did provide an inconvenient and expensive way to run PC programs and a relatively inexpensive route to hard disk capacity. If I recall correctly the PC ran independently but through “Janus” software the PC screen was accessed through a program running on the Amiga Workbench. There were also a bunch of utilities for sharing data and text between the two computers.

The processor above was supplanted by the almost perceptibly faster NEC V20 processor.

SCSI controllers and drives were insanely expensive, if technically superior, when the Amiga 1000 was ascendant. With a Sidecar you could get a relatively cheap PC hard disk controller and PC hard disks to share with the Amiga side.

All of this brings painfully to mind the startup scripts that I used to write and debug to deal with booting from a floppy, and handing off to the hard disk with subtle timing and software incompatibilities between booting with the Sidecar and LUCAS boards in different modes.

Comments
2 Comments »
Categories
hardware
Comments rss Comments rss

From Google Reader

Recent Posts

  • Merry Xmas 2008
  • Democracy
  • Our Apple TV experience
  • Goofy survey
  • Wondering if there is a dog

Navigation

  • games
  • general
    • family
    • kudos
    • links
    • vignette
  • manifesto
  • politics
  • silly
  • tech
    • hardware
    • networks
    • software

Shameless Advertising

rss Comments rss valid xhtml 1.1 design by jide powered by Wordpress get firefox