Re: Transwarp II photos posted online

[R.Kiefer.SPAM@gmx.de (Ralf Kiefer)]

Marcus wrote:

> http://en.wikipedia.org/wiki/Apple_II_accellerators

Oh, they've forgotten some more accelerator boards used in the Apple ][
and Apple //e.

After having used my AEs Transwarp @3,6MHz for some years I upgrated my
Apple //e a little bit:
In 1988 (or 1987?) I bought an accelerator board constructed by a
two-man-company in the south of West Germany (Leinfelden-Echterdingen).
I actually do not remember the company's name :-(  They did this mainly
to accelerate a chess computer. At this time these were mostly based on
the 6502. But they used the Apple ][ bus and offered this card also to
Apple users mainly running the processor with the NMOS instruction set
@10MHz. There were some cards running @12.5MHz and mine was running the
CMOS instruction set in a //e.

This card was build on two full length boards. Power consumption is 5A
@5VDC. I had to upgrade the power supply and added a fan (real Pentium
feeling ;-) ). 

The processor was based completely on PALs and standard TTLs.

The whole main memory of an //e was held onto this card (144kB SRAM
@50nsec, in 1988!). There is no code caching. The processor is forced to
synchronous 1MHz by hardware only running the low level disk driver at
slot 6. Screen memory is mirrored and written to mainboard memory in
background but never read from slow mainboard memory. The whole set of
soft switches is implemented "onboard" for reducing unnecessary access
to mainboard RAM. I/O except slot 6 is implemented "a bit" asynchronous.
If the last write access in background has not finished yet the fast
processor idles (in hardware) while waiting. Read access to slot
addresses is handled synchronous too.     

So my Apple //e was populated with the accelerator card at slot 7, disk
controller (2* 640kB) at slot 6 and some RAM discs at slot 5 and 4 (up
to 3MB). A nice little Apple //e :-)  Compiling & linking Pascal (UCSD)
software was really amazing. The speed of mass storage (RAM disk, my own
driver): reading 333kB/sec, writing 500kB/sec.

Assembling and linking the whole BIOS (SYSTEM.APPLE) was done in less
than a minute :-)  Later I implemented a terminal emulation (not VT100,
but similiar). I constructed a simple serial adapter based on a 6850,
baud rate 57,6kBaud, 7N1 instead of 8N1 because of speed :-)  Every
terminal command is finished before receiving the next character on the
serial line, except scrolling the original Apple//e 80col.  

The price in 1988: AFAIR 1900 DM (950 Euros).

Some elder photos:
http://tinyurl.com/396n3a
http://tinyurl.com/337ols
http://tinyurl.com/2tr6pt


Ralf