Path: utzoo!mnetor!uunet!portal!cup.portal.com!dick_a_wotiz From: dick_a_wotiz@cup.portal.com Newsgroups: comp.os.cpm Subject: Re: Fail to install P2DOS on Apple Message-ID: <4741@cup.portal.com> Date: 23 Apr 88 19:23:05 GMT References: <3414@zeus.TEK.COM> Organization: The Portal System (TM) Lines: 45 XPortal-User-Id: 1.1001.1002 > I promised Don Kirkpatrick a full report of what I did. Here it comes: > - my configuration is an Apple ][+ with 64 K of RAM, for running CP/M > I have a Softcard 60K with a Z80 processor. > . > . > addresses in image file addresses in high memory > ======================= ======================== > CCP: F00h - 17FFh CCP: D300h > BDOS: 1800h - 26FFh BDOS: DC00h > BIOS: 2700h - 2CFFh BIOS: FA03h > > P.S.: This are the addresses which I think the CCP, BDOS and BIOS > probably begin ? If NOT correct please let me know, because > the whole installation procedure falls or stands with it ! A while back I disassembled and analyzed CPM60.COM for CP/M 2.23 on my Apple II, and this is the memory map that it appears to use: CPM60.COM address memory address ----------------- -------------- BIOS 500h - AFFh B000h - B5FFh (in Language Card Bank #2) CCP F00h - 17FFh D300h - DBFFh BDOS 1800h - 1BFFh DC00h - DFFFh BDOS 1C00h - 26FFh B5C0h - BFBFh (in Language Card Bank #2) BIOS 2700h - 2CFFh FA00h - FFFFh Since the Apple only has contiguous memory from 0000h - DFFFh, it is necessary to split the BDOS into two parts; one is in high memory at DC00-DFFFh, where you would expect it to be, but the other half is in bank-switched memory, accessible only if the appropriate bank-switching routines are inserted into the DC00-DFFFh section of the BDOS. Likewise, the BIOS is split in two pieces in memory. I don't think there is any easy way of installing a different BDOS without very extensive modification/customization for the memory configuration that Apple uses. By the way, someone reminded me that this 'warped' implementation of CP/M is not Apple's fault, as I had implied in a previous posting. It was developed for them by Microsoft for the Softcard. (Hmmm.... aren't they one of Digital Research's competitors, anyway? :-) ) Dick Wotiz dick@portal.com dick@cup.portal.com ...!{uunet|sun|atari}!portal!dick