archeocomp
Experienced Member
Hello. I will probaly have more questions over time as I will progress. To get me started I would like to ask about the way CP/M boots. Suppose I have finished BIOS (which is not done yet) and I want to create bootable diskette. I have a col start loader in EPROM wich reads first sector. First sector contains begin address, end address and start address. Loader then reads consecutive sectors and stores them in RAM in the range begin->end. When it is done loading, it will jump to start address.
So far I know there is OEM CP/M version configured for 20k RAM. I believe I have found it on internet. It is a file CPM.SYS, size 7.5kB. This file must be loaded between 3400H-49FFH. BIOS follows between 4A00H-4FFFH. Start address is 4A00H
When the BIOS is correct CP/M should respond with A>
Now I want to reconfigure the system for 64kB. I could not find MOVCPM.COM in the same archive as I found CPM.SYS. I believe MOVCPM.COM is not always the same and is to be used with the right CPM.SYS right? Can I use other CP/M on the same machine (that I happen to have) to reconfigure OEM CPM.SYS for other RAM sizes? I am stuck right here now, hope someone can explain it better. MOVCPM.COM only moves BDOS+CCP and BIOS is up to me to recompile it for right address right?
So far I know there is OEM CP/M version configured for 20k RAM. I believe I have found it on internet. It is a file CPM.SYS, size 7.5kB. This file must be loaded between 3400H-49FFH. BIOS follows between 4A00H-4FFFH. Start address is 4A00H
When the BIOS is correct CP/M should respond with A>
Now I want to reconfigure the system for 64kB. I could not find MOVCPM.COM in the same archive as I found CPM.SYS. I believe MOVCPM.COM is not always the same and is to be used with the right CPM.SYS right? Can I use other CP/M on the same machine (that I happen to have) to reconfigure OEM CPM.SYS for other RAM sizes? I am stuck right here now, hope someone can explain it better. MOVCPM.COM only moves BDOS+CCP and BIOS is up to me to recompile it for right address right?