AppleCPM wrote:
> Hi!
> 
> On Feb 21, 2:11 pm, Steven wrote:
>> It's all simple economics.  I'm sure Alex would be glad to put up kits or
>> assembled boards at 20Mhz, but they're going to be more expensive.
>> FWIW, the upgrade is quite simple.  I just updated mine this morning (20Mhz.
>> crystal, 2x22pf chip capacitors and a faster Z80).  Went quick and
smooth and
>> runs like the wind!
>> The combination of the 20Mhz. Z80 card and my 12Mhz. ZipGSX equipped IIGS
>> should be quite responsive when I get that up and running.
>> FYI:  For those planning to upgrade memory to 512k, there is something odd
>> going on with the ramdisk that causes BDOS errors while writing.  Alex is
>> looking at it with a logic analyzer and I've been poring over the
source code.
>>   It's almost certainly a bug in the PCPI driver code, not the hardware.
>> Since the original Applicard could not be expanded past 256k of
banked memory,
>> I'm betting that some code path in there was never exercised and has always
>> been faulty.
> 
>     Arrrrrrggghhh!!!  My FedEx package with a 512K RAM chip, a 20 MHz
> Z80 CPU and a 20 MHz crystal is, according to tracking data, now in
> Barrington, NJ.  That's no more than 10 miles from here.  BUT, it
> won't be delivered until Monday.  ARRRRGGGHHH...

Relax!  For interactive tasks, the host is the limiting factor anyway.  An 
accelerator on the apple side will give you the biggest boost in keyboard and 
display "snappiness".  For computational throughput, obviously
the faster Z80 
will help.
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