Re: Let's say I do this......

[derek@slab.slip.uiuc.edu (Derek Taubert)]

>    Let's say I access a location in memory that does not exist.  In the
> books I have it says that the hardware is suppose to stop the command that
> is in the processor and cause a abort to be generated.  Is this so?  If not
> then what happends?

  Well, let me start by pointing out to you something on the schematic diagram
for the ROM 1 IIgs.  In the very back of the hardware reference, Part 1 of
the schematic, you will notice that the ABORT' pin (#3) is tied high by a 4.7K
resistor to +5V, and also connected to pin #32 of the Memory Connector.  That
is the ONLY connection to the ABORT' pin, period.  In fact, if you will look
earlier in the book, Figure 3-8 shows pin #32 of the Memory expansion slot as
being N.C. (not connected).  In other words, don't use it.

  Basically, the ABORT' pin is something that is available for use in the
processor, but not used at all by the IIgs hardware.  Maybe Apple had plans
at the beginning for some virtual memory device to be plugged into the Memory
expansion slot, but alas, none exists that I know of.

Enough said?

Derek