A500
The A500, also known as the Amiga 500, was the first "low-end" Commodore Amiga 16-bit multimedia home/personal computer model. It was released in 1987, at the same time as the high-end A2000, and competed directly against the Atari 520ST.
Technical specifications:
- Motorola 68000 (32-bit CISC microprocessor with 16 registers lacking MMU for memory protection and virtual memory)
- Default operating system AmigaOS 1.2 or 1.3 (having 32-bit pre-emptive multitasking microkernel) depending on the revision
- 512 KB of Chip RAM by default (sound buffers, graphics buffers and software existed in the same memory space)
- upper limit of 16 MB of memory due to MC68000 limitations (24-bit external address bus)
- OCS/ECS chipset
- 50 Hz PAL and 60 Hz NTSC TV output by default versions available; 50/60Hz mode switchable by software in later revisions
- software-switchable low-pass audio filter (power LED shows filter status, darker when off)
- IRQ sharing (like the PCI bus)
- IRQ system had 7 priority levels of interrupts
- No limit on number of interrupts available
- Resources handled by Autoconfig, very similar to ACPI, resources were not numbered or labelled, just given as amounts and addresses
- No specific I/O ports, instead using memory mapped I/O space separately for each hardware device (thanks to Jay Miner)
The A500 designation was also used on an internal Acorn Archimedes development machine .
