Hardware

Mac Boot Camp, part 5: Spindler. The diesel has landed

Apple needed a savior. It needed one that could raise it from the creative dead—one who would be a light and a redeemer. The Second Coming of Jobs was around the corner.


There is a time in Apple History known as the Interregnum. Lasting from the Reign of Sculley until the Second Coming of Jobs, it laid Apple low. Hubris swept the Building Of Marketers, as it did the Building Of Engineers—but for different reasons. The marketers thought they could conquer the world by letting the masses have the chance to buy the best machine. Anyone could see that Windows 3.0 sucked and that the Mac was better. Cost was not an issue if you wanted the best.
This article is part five in the "Mac Boot Camp" series by Larry Loeb. If you missed the first four articles or want to refresh your memory, here they are:
Mac Boot Camp, part 1: What’s a Mac program like? Mac Boot Camp, part 2: The managersMac Boot Camp, part 3: Mac hardware, the early daysMac Boot Camp, part 4: Cupertino strikes back
The engineers, on the other hand, were too busy playing with their new Crays to bother with piddling politics. VP of Tech Stuff Jean-Louis Gassee was supposed to speak for them, anyway. That Gassee might have his own technical agenda/turf fight going on bothered them not. It was just Management doing what Management does.

Out of the Spindlerian Era came some decent hardware and some marketer hardware. Sometimes they were even one and the same. The Mac II morphed into a line of Mac IIs, each model targeted to a market segment. Lots of Mac models sort of blurred together. There were the Classic (a 8 MHz MacPlus) and Classic II (a 16 MHz MacPlus), as well as the Mac LC (an IIci without the NuBus slots and FPU), the IIsi (a 20 MHz ci), Quadras (a 33 MHz 68040 IIci with two NuBus slots), and Performas (the “consumer” line). And that’s ignoring the four different Powerbook portables. Even Mac fanatics couldn’t tell the models apart after a while. The buying decision for a machine became inordinately complex. You had to guess what Apple would support over the long term.

The IIci seems like the typical machine of the Interregnum. It embodied all the hardware tweaks, including a 25 MHz 030 and a 68882 FPU and relatively easy access to internal hardware, should you want to change your own hard disk. The fact that it had three NuBus slots instead of six—the ci was compact—suited some users, especially since the video was built in and didn’t require a slot. It was a workhorse machine for that class of Mac.

But there was smoke around how the machine was sold. The marketers didn’t mention that the “high-speed RAM cache,” which gave the ci its “increased performance,” was a card that didn’t come with the basic computer. (The more cynical of us might remember that, at the time, memory prices were high and fluctuant. Populating such a cache card might have been very expensive if you had to go to the spot market.) Indeed, although there was a slot for such a RAM card on the ci, it remained mostly unused—even by the corporate buyers who seemed to like this model a lot. The cache cards that eventually showed up to boost performance were expensive and scarce. But the ci still seemed perfect for the associate’s desk. It could communicate via Ethernet, with a card in the NuBus slot. It had a fairly small footprint on a desk. You could talk to the corporate mainframe and still use Filemaker for a database.

The ci also made use of two General Logic Units, Apple’s custom chips: the MDU (memory decode unit) and the RBV (RAM-based video controller). The MDU interfaced the CPU to the rest of the computer circuitry. It generated the clock signals to synchronize activity. It also refreshed the dynamic RAM that was used for main memory. The MDU also allowed main memory and video memory to access RAM by generating separate addresses for the two banks of RAM that were present. The RBV chip helped to control the NuBus and cache cards. It also provided horizontal and vertical synchronizing signals for the video circuits.

On a Quadra, things were a bit more complex. The 040 had modes of operation, including burst. Four custom chips were needed to control the data traffic. The Junction Data Bus (JDB) and Relayer chips support separate data buses for system (main processor and memory) and for I/O interface. The JDB could do dynamic bus sizing and byte lane routing, and it could reset synchronization. It gave the system bus the ability to run faster than the I/O channel bus did. That way, the I/O operated in the same way as it did on a slower Mac. The Relayer generated I/O select signals, performed bus arbitration between system and data bus, and converted timing signals between the buses.

The MCU (Memory Control Unit) hung off the system bus and provided control and timing signals. All memory access modes of the 040 were supported by the chip.

The Direct Addressed Frame Buffer (DAFB) controlled the Quadra’s built-in video circuits and frame buffer. The video RAM of the screen buffer connected to the system bus at the highest possible operational speed through this chip.

The Enhanced Apple Sound Chip (EASC) also found its way into the Quadra line. It functioned in much the same way as the ASC chip, which was used in other Macs, but the EASC had pulse-code width modulation (PCM) as its output. The PCM went to a stereo digital-to-analog converter (DAC) and amplifier on a Sony-built sound chip and then to the speakers. Rumor had it at the time that Apple used these chips on the Quadra so that Sony would continue to supply it with the power management chips it needed for the Powerbooks, rather than from any direct technical need.

Multiple overlapping models. Buyer confusion. Lackluster sales. A lack of strategic vision. And despite the “look-and-feel” lawsuit filed, Microsoft was copying the Mac OS and successfully selling it to America. The end of the Spindler Era led to hard times for Apple.

Apple needed a savior. It needed one that could raise it from the creative dead. One who would be a light and a redeemer. The Second Coming of Jobs was around the corner.

Larry Loeb has 20 years of computer journalism experience. He was Consulting Editor at the late, lamented BYTE magazine, he launched WebWeek, he ran the online Macintosh section of BIX (the BYTE Information eXchange), and he wrote numerous articles for many major computer magazines. He also has written a book on Secure Electronic Transactions, the protocol endorsed by MasterCard and Visa that allows merchants, cardholders, and banks to work together over the Internet. For banter, tips, and general screaming, send Larry an e-mail .

The authors and editors have taken care in preparation of the content contained herein but make no expressed or implied warranty of any kind and assume no responsibility for errors or omissions. No liability is assumed for any damages. Always have a verified backup before making any changes.

Editor's Picks