If you are designing a pcb, forget about the 6264's as they're pretty well obsolete nowadays. Use a 684000 (also known under different numbers) which are 512k * 8.

Russell,

sorry, but I heavily doubt that 6264 becomes obsolete in the next years!! There are millions over millions of applications, which contain this 6264, and there will be lot enough request for this chip the next years.
If your statement were true, you would no longer get even 2114 or 6116. But neverteless they are readily availabe, and at very cheap prices!

But you are totally right: When Paul wishes to have big RAM, why not using 62256 instead of 6264s? Of course, he would make some changes then with decoding circuitry.

Anyway, Paul is an absolute beginner and is not able at the ready moment to plan memory banking and such stuff. He just wants to build this circuitry from his book, point by point. If things were different I would recommend him to proceed in another direction...


Paul,

did you already contact Steve? He offered you a big portion of help...

Kai