Re: Pet basic-2 save different than C64?

From: Marko Mäkelä <>
Date: Mon, 6 Feb 2017 18:12:15 +0200
Message-ID: <20170206161215.avj2bv5tir5kuaxd@hp>
Hi all,

On Mon, Feb 06, 2017 at 04:32:58PM +0100, Francesco Messineo wrote:
>For PC-CBM communications, I use a PC64 cable and cbmlink software.

Great to see that old technology still in use. :) Maybe some day I 
should try to port it to the Raspberry Pi. Maybe for an authentic 
feeling, use inline assembly and a setuid binary that would directly 
bit-bang the GPIO registers, like it was before /dev/parport was 
introduced to Linux.

>So what's the matter with it? I'm not very familiar with the PET (I
>was born with a VIC-20, then C64) but it seems it shouldn't be that
>much different in this respect. Is the save routine broken in some
>subtle way or my PET is?

What if you type just SAVE right after reset? Would it hang too?

Side note: About 31 years ago I got a broken 6510 in a C64 after 
hot-swapping tape drives to work around the azimuth angle trouble when 
copying tapes.  Everything else worked, but the SAVE command would cause 
the computer to hang. And guess if I had a backup of what was 
overwritten before I realized that it is hung? :) I guess that reads or 
writes of the on-chip I/O register would randomly fail, causing the 
KERNAL to be replaced with RAM in the memory map. Because screen was 
blanked during tape I/O, there was really no way to tell that it was 

>By the way, I could save the non-relocatable version directly from the 
>PET monitor, almost same size and it takes a few seconds.

Maybe the issue is that the end address vectors are wrong, and you are 
saving much more data? I am not that familiar with the PET either, and I 
gave away my PET collection over 7 years ago. Perhaps you could try to 
reproduce this on VICE?

Best regards,


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Received on 2017-02-06 17:00:07

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