cashe

■ 23 Feb 99 at 12:11:44 Roman Milukov addressed the following words to
Alexander Kormishin:

[...]
RM> Explain why you chose this particular port and this particular
RM> bit.
The port is quite old and widespread.
Bit5 in this port is still free. Those. There is no software that uses this bit for other
purposes yet, IMHO.
Well, and because I did it so long ago :), and it is clearly visible that the old software
works without glitches.

RM> And why "as a senior address"? Maybe it is better
RM> to use it as
RM> permission to use bit 4 #7FFD as the high address?
whether it is better or not is unknown. no one has tried it.
but extra parts appear and they will not add reliability.
RM> After all, some people may use a 32K microchip in
RM> as a cache, but there is no port
RM> #EFF7 and they are too lazy to do so. It will be enough for him to set the senior
RM> address to bit 4 #7FFD through the toggle switch
RM> and it will be 32K if turned on.
you can do that, of course. Only because someone will be
too lazy to assemble the #EFF7 port, I absolutely don’t want to get into an already
assembled and wonderfully working circuit. Also something like laziness.
and we need to get rid of toggle switches, and not create new ones.

Goodbye, Roman.

AK> you can do that, of course. Only because someone will
AK> be too lazy to assemble the #EFF7 port, I absolutely don’t want to get into the already
AK> assembled and wonderfully working circuit. Also something like laziness.

This is how all sorts of “standards” like the same “BAC - AY” appear, with which
everyone then sweats in unison. :(
No, first you need to think carefully, and then do it imho. And if you’ve done
not successfully, you need to redo it.

AK> and you need to get rid of toggle switches, and not create new ones.

Yes. That’s why I suggested one of the #CFF7 bits (your same port of “toggle switches”!)
use it as “enable cache-32K”, and the high address is bit 4 #7FFD.

All the best.
Sincerely, Roman.

09 Mar 99 01:26, Roman Milukov wrote to Alexander Kormishin:

RM> Yes. That’s why I proposed one of the #CFF7 bits (your port
RM> “toggle switches”!) to be used as “turn on cache-32K”, and the high address is bit
RM> 4 #7FFD.

And I also propose, especially since I have done it that way!

Kirill