Apple Technical Note HW 9 Macintosh IIfx The Inside Story
Macintosh Technical Note HW 9, "Macintosh IIfx: The Inside Story" is a five-page Apple Developer Support note by Rich Collyer, dated April 1990. It explains which programming techniques stop working on the Macintosh IIfx and what Apple offered in their place.[1]
Contents
[edit | edit source]The note is organised by subsystem:[1]
- ADB (p. 1): the ADB transceiver is behind an I/O processor (IOP), an Apple custom ASIC, and cannot be accessed directly; applications must use the ADB Manager.
- Driver and tool versions (pp. 1-2): the IIfx needs AppleCD SC driver 3.0.1 or later (as does the IIci), MacsBug 6.2 and, for SADE, MultiFinder 6.1b9, because earlier versions are incompatible. For the EtherTalk card Apple recommends driver 2.0.2, because earlier versions do not perform as well.
- NuBus (p. 2): a read-modify-write (TAS) cycle to a NuBus card followed immediately by an ordinary read or write hangs the system; Apple's fix is five NOP instructions between them.
- SCC (pp. 2-3): the serial controller has its own IOP with an "IOP Bypass" mode; the IIfx Serial Switch control panel chooses "Faster" (IOP) or "Compatibility" (direct CPU access). There is no VIA1 Wait/Request line, the vSync bit is not implemented, and the _HWPriv trap (selector 7) controls external SCC clocking instead. Synchronous SCC I/O with interrupts off hangs the machine.
- SCSI (p. 3): undocumented SCSI low-memory globals point elsewhere on the IIfx; see Technical Note DV 15 for termination. The IIfx has SCSI DMA hardware that the system software did not yet use.
- SWIM (p. 4): the floppy controller is behind an IOP; a new Sony driver control call returns raw disk data (Technical Note DV 17). Asynchronous disk I/O with interrupts off hangs the machine.
- VIA2 (p. 5): all of VIA2's functions have moved to other chips.
What this note does not contain
[edit | edit source]It is a software compatibility note. It has no electrical data, pinouts, power figures, board layouts or service procedures.[1]
Pages that cite this document
[edit | edit source]- Macintosh IIfx: the I/O processors and their effect on software.
Download: Apple Technical Note HW 9 Macintosh IIfx The Inside Story.pdf
References
[edit | edit source]- ↑ 1.0 1.1 1.2 Apple Computer, Macintosh Technical Note HW 9, "Macintosh IIfx: The Inside Story", Rich Collyer, April 1990, 5 pp. Hosted as File:Apple Technical Note HW 9 Macintosh IIfx The Inside Story.pdf.