The Macintosh II was introduced on March 2, 1987. The Macintosh II finally gave Mac users what they had been asking for since the successful introduction of the original Macintosh in 1984, a color-capable, expandable Mac with a separate monitor. The Mac II sold for $3,898 without a hard drive or $5,498 with an internal 40 MB hard drive[3]. The product team, headed by legendary Apple product developer Jean-Louis Gassée, began working on the Macintosh II in 1985. The company was about to embark on a new direction for its famed Macintosh platform.
The Macintosh II represented a break from the all-in-one "computer as appliance" formula that Apple and Steve Jobs originally envisioned for Macintosh. It was Apple's first attempt to place the Macintosh platform head-on with the expandable IBM compatibles. The Macintosh II was a completely different computer than the previous Macs. It was expandable, complicated, loosely configured, and very powerful. The previous Macs were tightly configured all-in-ones with closed-systems, which sacrificed performance for economy. The Macintosh II, on the other hand, was truly a monster Mac with six NuBus expansion slots, two 800K floppy drive bays and room for an internal SCSI hard drive. It was a box-monitor system with a removable top and expansion slots like the Apple II.
There are many images floating around the Internet showing the Macintosh II turned up on its side instead of laying flat with the monitor sitting on top of it. Apple specifically warned against blocking the airflow on the sides and bottom of the processor unit. The vents on the sides of the main unit were exhaust vents where heat could escape and the vents on the top were air intake vents. Apple also warned against placing the main unit on thick-pile carpet or upholstery[2]. Third party companies like Kensington offered a riser that would allow a user to safely lay the processor unit on its side.
The Macintosh II was powered by a single 16 MHz (15.6672 MHz clock frequency) Motorola 68020 processor with a standard Motorola 68881 floating-point coprocessor. Although Apple often claimed the Macintosh II had a 32-bit architecture, the Mac II ROMs were "dirty," containing some 24-bit code[3]. The Macintosh II used 24-bit addressing. Connectix Corporation, a third party Macintosh software developer, offered a program called Mode32 that allowed the II to run in 32-bit addressing mode. Connectix also sold an optional Motorola PMMU coprocessor that allowed the Mac II to use virtual memory with Mode32 in Mac OS System 7.
Standard memory was 1 MB, expandable to 68 MB, though not without a special FDHD upgrade kit; otherwise, 20 MB was the maximum. The Mac II had eight RAM slots that supported 120 ns, 30-pin SIMMs. Memory had to be installed in groups of four. The Macintosh II natively used 24-bit addressing, which had a RAM ceiling of 8 MB. Mode32 and 32-bit addressing was required to access more than 8 MB RAM. The Macintosh II could use 256K, 1 MB, 4 MB, and 16 MB SIMMs. 4 MB or larger SIMMs had to be PAL type. The use of 4 MB and 16 MB SIMMs required Apple M6051 upgrade (FDHD upgrade) or third-party accelerator supporting larger SIMMs. 4 MB and 16 MB SIMMs could not be used in Bank A without Apple's FDHD upgrade. RAM could be maxed out to 128 MB if the ROMs were upgraded to those used in the IIx (the Mac II's successor) and if Mode32 was used. The Mac II's memory controller supported higher-density memory modules than did the stock ROM[4].
The Mac II was introduced before Apple adopted the use of 1.4 MB floppy drives and would never ship with them. Apple offered an FDHD Macintosh II upgrade kit for the Mac II. The FDHD kit allowed the Mac II to read and write high-density 1.4 MB floppy disks.
The huge processor unit of the Macintosh II weighed in at 24 pounds and was almost 19 inches wide. This massive box dwarfed most of the monitors of the time. The Macintosh II did not have a built-in monitor connector and required a video card with built-in video memory. If the buyer did not purchase a fully-configured Mac II, the first set-up choir suggested by the Macintosh II Owner's Manual was to install a NuBus monitor card as the illustration shows below[1]. Resolution and VRAM depended on the monitor card.
Unlike previous Macs, control of the video signal was taken off the motherboard and moved to the monitor card. Apple initially offered two configurations. The basic video card had 256K of video RAM and could support 1 to 4 bits of data per pixel. This configuration supported up to 16 colors on screen at one time, or 16 levels of gray (using true gray scale). The original Macintosh used black and white bit-mapped patterns. The same video card could be expanded to 512K of VRAM, which gave a depth of 8 bits per pixel. The expanded card could display up to 256 colors or shades of gray at one time. The video card had a video lookup table on board of over 16 million colors[6].
Apple initially offered users a choice of two monitors: a 13-inch color monitor and a 12-inch black and white monitor. Both had 480 x 640 x 16 pixel resolution. Each pixel could have one of 16 shades. The color monitor required a special internal color monitor card[6]. At the time, many pundits expressed sheer joy at the richness of color the Mac II was capable of generating. Top of the line DOS systems of the day could only generate 64 colors at 640 x 350 pixels[3]. The Mac II's cutting edge graphics and color capabilities made it a very popular gaming computer in the late 1980s.
Apple introduced Mac users to NuBus expansion slots with the Mac II. NuBus was first developed at the Massachusetts Institute of Technology and was later used by Western Digital and Texas Instruments in their workstations. Representatives from Apple, MIT, AT&T, and Texas Instruments, among others, formed a committee to standardize the bus under the auspices of the Institute of Electrical and Electronic Engineers (IEEE). The NuBus used in the Mac II was actually slightly different from the final specification developed by the committee[7].
NuBus transferred data synchronously at a rate of up to 10 MHz. The bus consisted of 96 signal lines, including 32-bits of address and data, utility, and control lines, as well as power and ground signals. NuBus defined simple rules called the bus protocol, by which up to 16 boards, or devices could coexist on the bus at one time, although Apple chose to include only 6 slots in the Mac II. Unlike boards for the IBM PC expansion bus, NuBus boards did not require any address jumpers. Each board included its own configuration ROM that contained information, such as an initialization program or device drivers. The Mac II read the contents of the configuration ROM and installed the board automatically when the machine booted[7].
Apple continued the Macintosh II line for many years after its introduction. A year after the public release of the Mac II, Apple followed it up with the Macintosh IIx, a greatly improved computer with a more powerful 68030 processor. The last computer to share the Mac II form factor was the IIfx, introduced in 1990 with a "wicked fast" 40 MHz 68030 and a wickedly expensive $9,000 price tag. Apple trimmed the Mac II chassis down by seven inches with the introduction of the diminutive IIcx in March 1989 and improved on that form factor with the introduction of the IIci in September 1989. The II went low cost with the introduction of the affordable, yet powerful IIsi in 1990. The final form factor to share the II family name was the IIvx (and its low cost European cousin the IIvi). The IIvx's chassis lived on in the Performa 600 series and Power Mac 7000 series.
For information on the Macintosh IIx read "