Message: 4 Date: Sun, 16 Feb 2014 14:29:16 -0500 From: allison To: cctech@classiccmp.org Subject: Re: CPM3.SYS weirdness? Message-ID: <5301118C.2090508@verizon.net> Content-Type: text/plain; charset=ISO-8859-1 On 02/15/2014 12:41 PM, Chuck Guzis wrote: > On 02/15/2014 07:21 AM, Alexis Kotlowy wrote: >> Hello list, >> >> I'm attempting to bring up CP/M Plus on one of my Z80 computers by >> running CPMLDR.COM from CP/M 2.2. It crashes immediately after >> CPMLDR.COM jumps to CPM3.SYS (I'm sure this isn't surprising). I'm >> looking at the memory dumps and comparing them to the original file. It >> appears for every 128 byte block, the order is backwards. I.e. if I look >> at five 128 byte blocks on my PC they appear in the Z80's memory to be >> as 5, 4, 3, 2 and 1. Not the 'correct' way. > > Back in the day of MP/M and CP/M plus, I found it useful to get a > basic BIOS running on CP/M 2 first. Have you done this, using your > own de-blocking code? > > --Chuck > The BIOS is the critical element and best done with V2.2 first then the V3stuff added... Allison -------------------------------------------------------------------------------- Message: 6 Date: Mon, 17 Feb 2014 18:29:26 -0500 From: allison To: General Discussion: On-Topic Posts Only Subject: Re: CPM3.SYS weirdness? Message-ID: <53029B56.80905@verizon.net> Content-Type: text/plain; charset=ISO-8859-1 On 02/16/2014 05:19 PM, Alexis Kotlowy wrote: > On 16/02/2014 4:11 AM, Chuck Guzis wrote: >> Back in the day of MP/M and CP/M plus, I found it useful to get a basic >> BIOS running on CP/M 2 first. Have you done this, using your own >> de-blocking code? >> >> --Chuck >> >> > > I have CP/M 2.2 running already, using the example de-blocking code > provided by DR. I'm trying to boot CP/M Plus from CP/M 2.2 so I'm > using the existing file system from 2.2 to read CPM3.SYS, and the > existing functions from the 2.2 BIOS in CP/M Plus. > > I wrote a simple physical sector explorer to see what was being > written to the hard disk, which is an old 80MB ATA drive. Everything > is written in order, so I'm not sure what's going on. > > If there is a problem it's with my LDRBIOS.ASM file. I'll keep at it. > > Alexis. > the dri deblocker has a bug. I've never used it. Also for hard disks Skew is pointless and can slow the system. I believe that booting form CP/M 2 does not create a viable linked system. Allison -------------------------------------------------------------------------------- Message: 5 Date: Mon, 17 Feb 2014 23:26:49 +0000 (GMT) From: John Elliott To: cctech@classiccmp.org Subject: Re: CPM3.SYS weirdness? Message-ID: Content-Type: text/plain; charset=us-ascii > I'm looking at the memory dumps and comparing them to the original file. It > appears for every 128 byte block, the order is backwards. I.e. if I look > at five 128 byte blocks on my PC they appear in the Z80's memory to be > as 5, 4, 3, 2 and 1. Not the 'correct' way. I don't know if this is relevant, but records in CPM3.SYS are stored in reverse order; the first record after the header is loaded at the highest address, the next one 128 bytes below it, and so on. -- John Elliott ------------------------------ -------------------------------------------------------------------------------- Message: 1 Date: Wed, 19 Feb 2014 09:41:21 +1030 From: Alexis Kotlowy To: General Discussion: On-Topic and Off-Topic Posts Subject: Re: CPM3.SYS weirdness? Message-ID: <5303E899.3070501@kaput.homeunix.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed On 18/02/2014 9:56 AM, John Elliott wrote: > I don't know if this is relevant, but records in CPM3.SYS are stored in > reverse order; the first record after the header is loaded at the highest > address, the next one 128 bytes below it, and so on. > Yes, that would appear to be the case. Thanks. Alexis. --------------------------------------------------------------------------------