For those interested in the development of the Apple IIgs, I highly recommend reading "
The Apple IIgs Book". It goes into some of the development background of the machine. IMHO it kinda romanticizes some of the development choices but still a good read.
CPU Speed
The IIgs was never going to ship with a 8Mhz CPU in 1986. WDC had problems getting samples running much faster then 3Mhz at the time. Even by 1989 they had trouble with higher clocked CPUs as the Transwarp GS shipped clocked at around 7Mhz. AE had to "patch" the CPU using GAL logic in order to fix bugs. Later production cards and the ZipGSX ran at 8Mhz. I don't know much about the 90s development of the 65C816, but the CPU was finally stable (bugs fixed) when the modern CMOS versions arrived in the mid 90s. They were "rated" for 14Mhz, but usually ran at 20Mhz without a problem. The 14Mhz rating was due to limitations of WDC's testing equipment. This is the revision found in the CMD SuperCPU upgrades for the C64.
Platform Limitations
The biggest one is the 1Mhz bus limit. Any thing that hits the I/O space will throttle down the system to 1Mhz, including video. The VGC's frame buffer is stored in "slow" RAM. The system was designed as an 8-bit Apple II and extended to 16-bit using a 16-bit CPU and some glue logic called the "Fast Processor Interface". Anything on the CPU side (pretty much memory) ran at 2.8Mhz. The max theoretical transfer speed over the slot bus is 1MB/sec using tricks like DMA. Even a lowly IBM PC beats this with its 4.77Mhz bus speed.
The 65c832
WDC had put out a
datasheet outlining the "what if?" of a 32-bit ISA. It didn't get much further then that. Long term it would have been hard to justify this. The only folks clamoring for it would be Apple IIgs users with a large base of GS/OS and Toolbox friendly software. It's the only way Apple could have made a clean break from the wacky 8-bit Apple II architecture. The path Apple chose with the LC IIe Card was the correct one in many ways (although it would have been neat if it was a IIgs on a card). The only way a "modern" Apple II could exist is the same way things were done on the PC, a hardware based virtual machine to run old software on a modern OS. Apple wasn't going to do this with the Macintosh hanging around!
Apple's Multimedia Intentions
This one is quite baffling. It involves the Apple II Video Overlay Card, a product that really shouldn't have existed (unlike, say the Ethernet card that was canned at the last minute). The board itself was VERY expensive to design and sell. It used a ton of VLSI chips and the most modern of manufacturing methods for 1990. Going by the promotional materials, Apple was clearly trying to target the educational group and check off the "see we have a genlock too!" box against the Amiga and Atari STe. Well, except those machines came with all that built in.
The end goal was likely to base the Apple IIgs as a heart of an interactive LaserDisc system. Hypercard would power the application, the VOC would provide UI overlay, while a serial controlled LaserDisc player provided the video and pretty menus. All for a ridiculous price that no school would pay for. The only other thing the VOC was good for is adding Apple IIgs SHR video modes to the IIe, or 400 line (interlaced!) output to a IIgs. Otherwise, pretty useless unless you want to watch TV on your AppleColorRGB monitor.
My high school did have an Apple IIgs controlling a LaserDisc player for interactive educational work. It didn't use the VOC, but something way more unexpected. The machine booted into AppleWorks and used Time-Out! macros to control the LaserDisc player!
Apple's "Investment" in the IIgs
In hindsight, it was remarkable the machine lasted as long as it did. It took Apple TWO years to release a proper operating system for the machine. It shipped with the Apple II DeskTop (MouseDesk) as a GUI for the first year or so. It later got a IIgs native Finder in 1987. All this was based on the ProDOS 16 core, which was basically the 8-bit ProDOS extended with the IIgs Toolbox. Disk access was DOG SLOW.
When GS/OS showed up in 1988, the native 16-bit disk code was much faster and they finally added a disk cache. Apple poured a ton of money into the OS on this machine for some reason. It many ways it was more advanced than classic MacOS (software loadable file system translators among other things). I guess that's what happens when you learn from your mistakes. Reading period Usenet posts, its clear that people were very unhappy with how long it took Apple to release all this stuff.
The same folks were also very unhappy when the ROM 3 showed up. It was pretty clear the machine needed more CPU horse power and a built-in SCSI controller, neither of which it got. The only thing the ROM 3 solved was the lack of RAM. A base IIgs with 256k (less actually available for programs) is pretty useless and only a handful of native software can run with that. Almost all games needed at least 512k, which Apple later made standard by including a RAM card.
To end things, Macintosh users should be very grateful to the Apple II line. It was Apple's cash cow that subsidized the Macintosh for at least the first 3 years of it's life..... maybe longer.