From mboxrd@z Thu Jan 1 00:00:00 1970 From: tfb@tfeb.org (Tim Bradshaw) Date: Tue, 28 Nov 2017 14:55:46 +0000 Subject: [TUHS] Harvard and Von Neumann Architectures and Unix In-Reply-To: <20171127161141.2C9E318C08F@mercury.lcs.mit.edu> References: <20171127161141.2C9E318C08F@mercury.lcs.mit.edu> Message-ID: <2E06126D-C247-4D2B-97A2-DE0A449594E4@tfeb.org> On 27 Nov 2017, at 16:11, Noel Chiappa wrote: > > Along those lines, I was wondering about modern OS's, which I gather for > security reasons prevent execution of data, and prevent writing to code. > > Programs which emit these little 'custom code fragments' (I prefer that term, > since they aren't really 'self-modifying code' - which I define as 'a program > which _changes_ _existing_ instructions) must have some way of having a chunk > of memory into which they can write, but which can also be executed. I think, however this is done, it must be relatively tractable, because Lisp systems with native-code compilers work fine on modern OSs, and they do very much more than generate small code fragments. --tim -------------- next part -------------- An HTML attachment was scrubbed... URL: