Atari Mega ST 4

The Atari Mega ST 4 was the four-megabyte flagship of Atari’s 1987 professional ST range. It combined the familiar 8 MHz Motorola 68000 and ST graphics architecture with a desktop enclosure, detached keyboard, internal floppy drive, BLiTTER chip, real-time clock and proprietary expansion bus.

Its larger memory was valuable for page layout, graphics, software development and music applications, while compatibility with Atari’s laser printer supported comparatively affordable desktop-publishing systems. The Mega ST 4 remained the most capable original ST architecture model until the faster Mega STE arrived.

Notable Features

• 4MB of RAM, the maximum normally addressable by the original ST architecture.
• Desktop case, separate keyboard, BLiTTER, real-time clock and Mega expansion bus.
• Supported Atari’s direct-connect SLM804 laser printer.

Historical Significance

• Served as Atari’s flagship professional computer from 1987.
• Found a niche in desktop publishing, music studios and graphics work where its memory and high-resolution monochrome display were valuable.

Collector’s Notes

• A complete matching keyboard is essential because it is separate from the system unit.
• Original Mega ST 4 badges and unmodified 4MB configurations are desirable to collectors.

Specifications

Technical Information
Name	Atari Mega ST 4
Manufacturer	Atari
Launched	Wednesday, July 1, 1987
Discontinued	1990
Launch Price	US$2,399 with monochrome monitor
Country	United States
CPU	Motorola MC68000 at 8 MHz
Units Sold
I/O	MIDI In/Out, RS-232 serial, Centronics parallel, ACSI, cartridge, monitor and joystick/mouse ports
Expansion	Mega expansion bus and detached keyboard
Storage	Internal double-sided 3.5-inch 720KB floppy; ACSI hard-disk support
Sound	Yamaha YM2149 three-channel programmable sound generator
Graphics	Atari Shifter with BLiTTER graphics accelerator
Colour Palette	512 colours
Display	320x200 in 16 colours, 640x200 in 4 colours, or 640x400 monochrome
ROM	TOS in ROM
RAM	4MB
CPU Speed	8 MHz