Apple  Macintosh II-X
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Macintosh IIx

The Macintosh IIx was manufactured from 1988 to late 1990. It is an upgrade to the Macintosh II and has some key updates.

The x in the name signifies that this machine has the 030 version of the 68000 CPU series. The older Motorola 68020 CPU is replaced with the 68030 and the 68881 Floating Point Unit is replaced with the 68882. The system has an upgraded 1.44MByte SuperDrive which replaces the 800KByte in previous models. The system bus is now running at the same 16MHz speed as the CPU and the CPU got 256Bytes of L1 instruction cache.

The case is also roomier, it allows for two floppy drives and can support 6 NuBus expansion slots.

Macintosh IIx

Motorola 68000 CPU Family

The Motorola 68000 is a 16/32-bit microprocessor that was first released in 1979. It was widely used in computers and other electronic devices during the 1980s and early 1990s. The 68000 was known for its advanced architecture, which included a 32-bit internal bus and a 24-bit address bus, allowing it to access up to 16 megabytes of memory. This made it more powerful than many other processors of its time, such as the Intel 8086 and Zilog Z80. It was also designed to be highly modular and expandable, with a large number of on-chip and off-chip peripherals.

Some of the most famous and successful computers that used the 68000 was the Commodore Amiga and the Atari ST, both of which were popular in the home and personal computer markets. Additionally, it was also used in workstations, such as the Sun 3 and Apollo DN3000, and in a wide variety of embedded systems and industrial control systems. The 68000 was also used in the Macintosh, the first model of the Macintosh was powered by a Motorola 68000 CPU. The processor was eventually succeeded by the 68020 and 68030, which offered improved performance and additional features.

The 68000 has a 32-bit instruction set, with 32-bit registers and a 16-bit internal data bus. The address bus is 24-bit and does not use memory segmentation, making it easier to address memory. There are three ALU's (Arithmetic Logic Unit), two for calculating addresses, and one for data, and the chip has a 16-bit external address bus.

The 68000 architecture was expanded with 32-bit ALUs, and caches. Here is a list with some 680x0 versions and their major improvements:

  • 68010 - Virtual memory support
  • 68020 - 32-bit ALU & Instruction Cache
  • 68030 - On-Chip MMU, 2x 256 byte cache
  • 68040 - 2x 4K Cache, 6 stage pipeline, FPU
  • 68LC040 - No Floating Point Unit (FPU)
  • 68060 - 2x 8K Cache, 10 stage pipelinet

Technical Details
Released 1988 Brand Apple Type Apple Macintosh II Name Macintosh II-X CPU Class 68000 CPU Motorola 68030 @16MHz Memory RAM: 1MB
RAM max: 8MB
Sound Chip TTL Logic for PWM Sound 8-bit Pulse-width modulation Display Chip none Display 640x480 4-bit color
512x384 8-bit color.
Best Color 8 bit color Best Graphics 640x480 4 bit color Sprites none System OS MacOS System 6 or 7
Related Systems
Apple Series I
Apple Series II
Apple Series III
Apple Macintosh
Apple Macintosh II
Macintosh  II-X (1988)
Apple Macintosh LC & Quadra
Apple Newton
Related Media
Apple Macintosh
Books about the Apple Macintosh, the first mass-market personal computer with a graphical user interface.
68' Micro Journal
Magazine devoted to the 68xx user
InCider and A+
InCider Magazine for Apple Computers, later fused with A+
Peeker Magazine
Peeker, a German language magazine for Apple Computer users.
World Wide Web Links
Wikipedia: Motorola 68000 CPU Family
WikiPedia page on the Motorola 68000 series of processors