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Remembering the 6502
Jan. 7th, 2011 07:41 pmI have mentioned before that I am a fan of the archeology series Time Team. I love the whole uncovering the past thing. But there is one thing that always niggles when I watch it. It is something that Mick Aston comments on from time to time in the show. It is that much of the archeological analysis done is essentially destructive in nature. Every trench disturbs and damages what is being studied. Now I'm not being critical of the archaeologists in this. They are aware of the issues and try to minimise the impact of their work. Not forgetting that much study is undertaken because development or erosion is going to destroy it anyway. The important thing is that what is destroyed as part of investigation is recorded.
That last bit is the bit that triggers those little niggles. Just how good is that recording. One of the perils of the information age we are currently undergoing is that with so much around that bits can get lost so easily. The changes in storage technology mean that even if you have the info, you may not be able to read it. I just wonder what is going to happen to all those geophysics and GPS data that I see on Time Team. Probably backed up on floppy disks that nobody can read now. Well a few people can read it, but that few keeps declining in number.
All of this ramble came to mind because of this article which notes that the design schematics etc for the MOS 6502 chip have been lost. This isn't some thousand year old post hole we are talking about here. It is probably less than 40 years old and is one of the key components of the early days of the microprocessor revolution. Amongst other computers, it powered the Apple ][ - the very first computer that I actually owned.
Hope remains however. Some folk have taken some of the chips apart layer by layer to figure out how it works. And here is the really cool part - they have made a visual simulator. You can actually see how voltage levels change as individual instructions are executed. I don't know what it represents, but it looks great.
That last bit is the bit that triggers those little niggles. Just how good is that recording. One of the perils of the information age we are currently undergoing is that with so much around that bits can get lost so easily. The changes in storage technology mean that even if you have the info, you may not be able to read it. I just wonder what is going to happen to all those geophysics and GPS data that I see on Time Team. Probably backed up on floppy disks that nobody can read now. Well a few people can read it, but that few keeps declining in number.
All of this ramble came to mind because of this article which notes that the design schematics etc for the MOS 6502 chip have been lost. This isn't some thousand year old post hole we are talking about here. It is probably less than 40 years old and is one of the key components of the early days of the microprocessor revolution. Amongst other computers, it powered the Apple ][ - the very first computer that I actually owned.
Hope remains however. Some folk have taken some of the chips apart layer by layer to figure out how it works. And here is the really cool part - they have made a visual simulator. You can actually see how voltage levels change as individual instructions are executed. I don't know what it represents, but it looks great.