CBM Amiga 500 (1987)

Features

CPU: Motorola MC 68000 7.14MHz
Co-Processor: Agnus (MMU), Denise (video), Paula (Sound & I/O)
RAM: 512 KB (expandable to 9MB : 512 KB CHIP RAM + 512 KB Slow RAM + 8 MB FAST RAM)
ROM: 256 KB (DOS 1.2)
Text Modes: 60 x 32 / 80 x 32
Graphic Modes: 320 x 256 / 320 x 512 / 640 x 256 / 640 x 512
Colors: 32 (for 320 x X modes), 16 (for 640 x X modes) among 4096 + 2 Special modes: EHB 64 colors and HAM 4096 colors on static display.
Sound: 4 voice 8 bit PCM
I/O Ports: Centronics, RS232, Mouse, Joystick, RGB, Composite, External Audio, Bus
Built in Media: one 3.5” disk-drive
OS: AMIGA WorkBench 1.2 (first deliveries) then 1.3

Usage

MESS emulates the following computers

a500n [Amiga 500 (NTSC, OCS)]
a500p [Amiga 500 (PAL, OCS)]

For both drivers, MESS supports

two floppy drives, “floppydisk1” (flop1) and “floppydisk2” (flop2), for disk images in .adf format.
a “cartridge” (cart) device, for cart dump in .rom and .bin format

These systems require full keyboard emulation to work correctly. At startup, full keyboard emulation mode is enabled by default. Whilst in full keyboard emulation mode, some key associated functionality may be disabled (like the ESC key for EXIT). The keyboard emulation mode is toggled using the “Scroll Lock” key (by default).

BIOS options

MESS supports various Kickstart ROM versions: v1.2, v1.3, v2.04, v3.1. You can switch between them, changing the -bios parameter. At command line,

"-bios 0" or "-bios kick13" = Kickstart 1.3 (34.5)

"-bios 1" or "-bios kick12" = Kickstart 1.2 (33.180)

"-bios 2" or "-bios kick204" = Kickstart 2.04 (37.175)

"-bios 3" or "-bios kick31" = Kickstart 3.1 (40.63)

Known Issues

The driver is now working fairly well, though some games may need more memory than currently emulated. The graphic emulation of these systems is known to be imperfect.

History and Trivia

The Commodore Amiga 500 was the low-end successor of the Amiga 1000 and the predecessor of the Amiga 1200. It was the main competitor of the Atari 520 STf (there was a great “war” between the owners of these two computers).

It used a special system for its RAM configuration: 512 KB of Chip RAM which could be accessed by the Paula and Denise custom chips (sound & I/O and video, respectively) and Fast RAM which could be accessed only by the CPU.

The 68000 bus had two connectors, an external and an internal one. An extension card could be added through the internal connector on bottom of case and offered 512 KB of additional RAM and a battery-backed clock.

The Amiga 500 was followed by the Amiga 500+. The Amiga 500+ had the same characteristics as the Amiga 500 except it had 1MB of Chip RAM and used the AmigaOS 2.04, this version of Amiga OS needed 512 KB of ROM.

The Amiga A500+ was the shortest lived Amiga, lasting only 6 months before being replaced by the A600. Ironic that a machine designed to be cheaper and sold 'below' the 500+ should replace it and be sold for the same price(!)

Both versions could be connected to a TV set or to a video monitor with a better resolution. Two Amigas could be networked using a null modem cable.

This computer was, and is still used a lot in the “demoscene” to create cool videoclips with breaking graphics and sounds!

(info from old-computers.com)