A500

The A500, also known as the Amiga 500, is an Amiga personal computer model. It was released in 1987 at the same time as the A2000.

Some 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 same memory space).
  • upper limit of 16 MB of memory due to MC68000 limitations.
• OCS/ECS chipset.
• 50 Hz PAL and 60 Hz NTSC by default versions available. 50/60Hz mode can be switched by software.
• software switchable low-pass audio filter. (power led show filter status, darker when off)
• IRQ sharing (like PCI bus).
• IRQ system had 7 priority levels of interrupts.
  • Absolutely 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, used memory mapped I/O space separately for each hardware device (thanks to Jay Miner).