ANDRExxx
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If you could remember (or look up) just how this is done, I like to know. Is there a way of examining the bootrom with DDT or some similar tool? The K-10 manual treats the Bank 1 prom as some kinda black box. The so-called memory map just shows it a single block of memory. (I know they don't need 16K for just a bootloader, I'm curious what else might be in there). The note at the bottom of the memory map page reads:Barry said:The fact that it has a Z80 doesn't tell you anything about it's screen arrangement. A lot of computers have screen memory but you can't always use Basic to poke into it.
The Kaypro 10, for example, had the screen memory in a switched out memory bank that had to be switched back in first and I don't think you could do that with a simple poke from Basic. I don't remember the details. There may have been a way to do it. But I'm pretty sure a poke by itself wouldn't do it.
Most CPM systems probably didn't have screen memory at all since they were terminal oriented machines without a built-in terminal. They just sent commands to the terminal, which took care of the details.
My only experience with CP/M was on a Kaypro 10 so I'm not sure of what I'm saying here but I think I'd bet on it. I do know the Kaypro 10 was unusual in that it did do graphics and that it did have a built-in terminal.
Barry
If you could remember (or look up) just how this is done, I like to know. Is there a way of examining the bootrom with DDT or some similar tool? The K-10 manual treats the Bank 1 prom as some kinda black box. The so-called memory map just shows it a single block of memory. (I know they don't need 16K for just a bootloader, I'm curious what else might be in there). The note at the bottom of the memory map page reads:
"Please note that only the lowest 16 Kbytes of memory will change with the bank select bit; addresses above 7FFF hexadecimal are always available for either bank."
Nowhere else in the Kaypro documentation is the "bank select bit" mentioned. Do you know how to access (change) this bit?
Sounds like your Kaypro had some memory
segments (which is what the IBM has). In
case of an IBM you'd need to change the
Segment (in BASIC this was DEF SEG=segno)
'segno' could have been B800h or A000h (for
the newer Video Cards - e.g. VGA).