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PyCon: Eben Upton on the Raspberry Pi

Posted Mar 21, 2013 17:15 UTC (Thu) by nix (subscriber, #2304)
In reply to: PyCon: Eben Upton on the Raspberry Pi by wookey
Parent article: PyCon: Eben Upton on the Raspberry Pi

That really doesn't matter. The BBC B, the ZX81, the C64, all of those were every bit as proprietary. People dug into the guts and figured out how they worked. My only worry is that these days, if people try to publish disassemblies and the like, they'll get sued by the likes of, well, Broadcom...

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Posted Mar 21, 2013 18:39 UTC (Thu) by pboddie (subscriber, #50784) [Link]

The hardware above the chip level was documented in the manuals for the Acorn machines and I've seen a pretty thorough manual for the Amstrad CPC series that upholds this level of documentation. Most of the ICs were commodity components, and the only notable exceptions in the Acorn machines (and in the Sinclair machines) were the ULAs, for which you did get a block diagram in the former case.

Ignoring the physical reverse engineering done on various ULAs, particularly the successful work done on the Spectrum's ULA, it is completely possible to logically reverse engineer these components, and I believe that various emulators actually achieve reasonable accuracy. An interesting test would be to actually try and use such software to drive the hardware and see how compatible the implementation is, although I imagine that you'd need to put work in to do things like refresh the DRAM and other bus signalling that "just happens" in an emulator.

Of course, the software in the microcomputers of that era was proprietary and disassembly listings that were actually published in books did lead to legal action. So some things haven't changed at all.

(I wrote this stuff up here.)

PyCon: Eben Upton on the Raspberry Pi

Posted Mar 21, 2013 19:28 UTC (Thu) by mpr22 (subscriber, #60784) [Link]

You didn't need to dig very hard on the C64, at least Stateside; the same stores that sold C64s also sold a $19.95 book documenting its internals (including schematics, pinouts, the 6510 instruction set, the memory map, ...)

PyCon: Eben Upton on the Raspberry Pi

Posted Mar 21, 2013 20:30 UTC (Thu) by wookey (subscriber, #5501) [Link]

I wasn't comparing with the 1980s, but with other much more open platforms of recent years. Two I've been particularly involved with were the lart and the balloonboard. More recently things like beaglebone (yeah I know, powerPV GPU lets it down). The Pi's lack of freeness wouldn't matter if they didn't go on and on about the openness, which is pretty ironic given that it comes out of Broadcom. There have been plenty of very misleading statements (all that hullabaloo about their free graphics driver for example). If they didn't say that stuff then it wouldn't make me grumpy.