Re: Accelerating the CPU!

[Rubywand <rubywand@swbell.net>]

Jason Compton wrote (7/5/97) ...
> 
> Rubywand (rubywand@swbell.net) wrote [7/3/97]:
> :      C-64 users have a couple of big advantages: They have a very simple
> : machine; and, they do not much care whether or not their 20MHz '816 board
> : will run their old wares.
> 
> <snort at both comments>
> 
> I'll take your inflammatory remarks in good humor. :)
> 
> :     _IF_ we are willing to blow-off running old-][ and GS wares on a GS Super
> : Card, then, a major plug-in upgrade is entirely doable at reasonable cost.
> : 20MHz (and better) speed, 16MB-64MB RAM, improved Sound, vastly improved
> : display, ...  everything falls into place when you go with a fresh new
> : design.
> 
> The 20mhz '816 board actually does a surprisingly GOOD job of running old
> software, and that compatibility is of primary concern since there's
> really no SuperCPU-only software right now.
> 
> It is true that anything that calls undocumented opcodes will likely fail,
> but most applications and a surprisingly high percentage of games work
> just fine.  Some don't work quite the way you'd like them to at 20mhz, but
> others get a very enjoyable speed increase.  And GEOS has been patched to
> run beautifully.
> 
> So 64 users aren't just dumb hicks with money to burn.  CMD's done a great
> job with the SuperCPU.
> 
>

     The original observations and follow-up questions (7/5/97) aim to explore 
the trade-offs involved in a significant Apple IIgs Speed/Memory/Display upgrade. 
Since C-64 and C-128 users seem to be engaged in a major upgrade, their 
experience is of interest.


     A check of the C64/128 FAQ's reveals the following:

>>

The CMD Super 64 CPU accelerator cartridge, currently shipping from Creative 
Micro Designs, will allow a Commodore 64 or Commodore 128 (in 64
mode) to reach CPU speeds of 20 MHz. 

A Western Design Center 65C816S 16bit CPU core (with 6502 emulation) forms the 
heart of the unit.  The accelerator is compatible will all standard peripherals 
for the Commodore 64 ....                                   
                                                   
Internally, the unit contains a WDC 65C816S CPU and 64kB of fast static RAM for 
no-wait program processing.  Both a stock and JiffyDOS enhanced kernel are 
available, and the user can completely disable the unit if desired without 
unplugging.  Also, the speed of the unit (1MHz or maximum speed) can be selected 
via switch or software.  A pass through port allows the user to use existing 
cartridges, and an expansion port dubbbed the "Rocket Socket" allows RAM or 
functionality enhancements to be added to the accelerator.

  Production units began on July 25, 1996, and a developer's package
  will be made available to software authors shortly.

<<


Super 64/20 price is $199.00
from Creative Micro Designs
(800) 638-3263 (Orders only)
(413) 525-0023 (Information)
cmd.sales@the-spa.com (Information and Pricing)

CMD is supposed to be working on a 20MHz accelerator for C-128 in '128 mode.


     There appear to be two ways to access a hard disk on a C-64. One is to add a 
hard disk available from CMD; another is via software and a cable connection to a 
PC with a hard disk.

     There are various ways to add bank-switched memory to a C-64 or C-128.

     Regarding C-64 display upgrades, the FAQ explains that various chip swap-in 
mods allow higher res in text mode. Evidently, there is no mod available to 
improve color graphics resolution.

     The FAQ mentions mods which allow a C-128 to get up to 720 x 700 resolution. 
Max colors are said to be 16.


     Some 'flagship' vendor/developer, like CMD, may be able to lead a goodly 
number of C-64 and/or C-128 users toward reasonably 'standard', significantly 
enhanced versions of their machines. If so, then, some programmers may produce 
games and other wares which take advantage of such improvements as the Super 
64/20 accelerator.

     In any case, it is clear that the new machines will not, in general, be 
running old wares in 'new machine' mode. A few wares, like GEOS, will be 
converted. Otherwise, compatibility will be maintained by permitting the user to 
switch OFF the enhancements in order to load and use older programs.


     The IIgs has already undergone notable enhancements. However, efforts to 
produce the next round of significant, badly needed upgrades have run into a 
'brick wall'.

     Patchwork upgrades, such as the Zip-GSX accelerator, Second Sight, and 8MB 
expansion cards are unsatisfactory because, for decent performance, the upgrades 
must be integrated. For example, low main bus speed means that gains from 
increasing accelerator speed shrink with each step.

     Since we want to be able to run old-][ and current GS wares, about the only 
upgrade which makes sense is plugging in a 'new machine'-- one which can, except 
for display translation, be switched OFF (or around) to allow running older 
software. If the upgrade were housed in a case a bit larger than the System Saver 
GS (with a fan, etc.), it could have its own power supply, I/O sockets, etc. and 
fit neatly atop the GS in place of System Saver.

     Like C-64/128 users, we would have reached an end-point in enhancements 
compatible with current wares. GSOS, for example, would work fine in the old-GS 
mode; it would have to be rewritten in order to function in the new-GS mode on 
the new hardware. On the other hand, we would have a much bigger, faster GS with 
the sound and display to handle net applications, major games, and anything else 
we might wish to develop.   


Rubywand