The applets in this chapter demonstrate the Intel MCS4 system ("Microcomputer System 4-bit"), the first single-chip microprocessor system in history. Despite the complicated memory architecture with separate program- and data-memories, and despite the somewhat incomplete instruction set, the processor and system architecture provide a very interesting engineering solution. While the MCS4 was soon replaced by much better 8-bit systems, it still paved the way for the microprocessor revolution. The first applet page includes an overview of the architecture and external links to MCS4 documentation, datasheets, and trivia.

	Intel MCS4 (i4004) Overview	applet	webstart	print
	Intel MCS4 (i4004) binary addition	applet	webstart	print
	Intel MCS4 (i4004) BCD addition	applet	webstart	print
	Intel MCS4 (i4004) binary subtraction	applet	webstart	print
	Intel MCS4 (i4004) BCD subtraction	applet	webstart	print
	Intel MCS4 (i4004) addition with RAM	applet	webstart	print
	Intel MCS4 (i4004) subtraction with RAM	applet	webstart	print
	Intel MCS4 (i4004) increment in a loop	applet	webstart	print
	Intel MCS4 (i4004) increment on TEST-signal	applet	webstart	print
	Intel MCS4 (i4004) calculator	applet	webstart	print
	i4003 serial-in parallel-out shift-register	applet	webstart	print
	Intel MCS4 I/O ports	applet	webstart	print
	Intel MCS4 (i4004) Counter with Multiplexed Display	applet	webstart	print