Re: Questions about IWM

["David Wilson" <mcs6502@gmail.com>]

PZ wrote:
> http://apple2.org/images/InterfaceCards/images/Hard.FloppyDisk/image-html/UnivCTRL'r.html

Cool, I have never seen that card before.

> The IWM Disk II controller shows exactly how much of the original Disk
> II controller is inside the IWM, pretty much all of it.  What got
> consollidated:
>
> 556 - essentially a Dual 555 timer
> 74LS00 - only 1 AND gate is used.
> 74LS05 - handful of high output inverters
> 74LS132 - some Schmitt Triggers
> 74LS174 - handful of D-type Flip-Flops
> 74LS259 - 8 bit addressable latches
> 74LS323 - 8 bit universal shift/storage register

You missed the 256 byte state machine PROM (the Disk II has two PROMs
while the IWM card only has the one containing the boot code).