Msg: 5115 *Conference*
06-13-94 16:32:44
From: COMET _
To : ALL
Subj: MEMORY EXPANSION
I have received a copy of the catalog of the club. There are a few (incompatible) ways to expand memory. I understand bank-switching <my 1977 Atari Video Computer System (VCS) has several game program cartridges which use bank-switching> and am hoping you all would give me some advice. I want to know which system would allow the most RAM total. Also, I am interested in some details of implementation: it would be nice to be able to write programs that use more than 29638 bytes of memory. I think that the bank-switching is accomplished by writing values to some output port, but if my program gets switched out, the program counter register in the CPU will still want to go to the next address... how do I get the program to continue on the next bank? How much (if any) global area is there? Is the only read/write locations that are saved when banks are switched the port address space and the registers? How about display memory? Is that banked, too? And how about memory controlled by other chips, like DATE/TIME/DAY? Since I am interested in programming, myself, far more than in using already written programs, these details matter to me more than knowing what programs are available that actually make use of these features. I enjoy my Model 100, and enjoy learning about ROM routines and machine language programming. I have a bookshelf full of books on recreational/scientific computing. I wrote my own disassembler (of course), but hand-assemble my programs, to save space. (I write my programs on paper, first, flowcharts and all.) I look forward to hearing a technical overview comparing and contrasting the various devices available here to expand memory. I *will* buy! :)