why is there not a lisp pc?
in [Lisp]
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From: Tamas K Papp on 19 Jan 2010 07:46 On Tue, 19 Jan 2010 13:28:57 +0100, Frode V. Fjeld wrote: > Tamas K Papp <tkpapp(a)gmail.com> writes: > >> The internet just leads to a higher chance of having someone else's >> application run on your computer. Imagine having desktop Lisp machines >> today, with x86-like speed but the same security model. Would you >> browse the web on that? > > I don't get it. Are you saying you feel safe about firing up any > executable file you find floating around the internet because the unix > (etc) security model is going to protect you? I believe the current > "best practice" implies that all bets are off once you do that, unless > you very painstakingly set up a sandbox. Not necessarily the unix security model, but yes, sandboxes are a good idea. And they are not painstaking at all -- see eg Firefox. In contrast, AFAIK a sandbox as I understand it would be impossible on the original Lisp machine (unless you are willing to have a virtual machine run inside it). > What unix has is the ability to have multiple security domains on a > single system, which was crucial back in the eighties or so. Now we have > Personal Computers. Plural. I don't understand what you are trying to say. Anyhow, I don't mean to imply that it is impossible to come up with an architecture for a Lisp machine that would have better separation of privileges, just that it is my impression that the original architecture was not evolved in that direction at all. Tamas
From: Frode V. Fjeld on 19 Jan 2010 07:54 Tamas K Papp <tkpapp(a)gmail.com> writes: > Not necessarily the unix security model, but yes, sandboxes are a good > idea. And they are not painstaking at all -- see eg Firefox. In > contrast, AFAIK a sandbox as I understand it would be impossible on > the original Lisp machine (unless you are willing to have a virtual > machine run inside it). I don't know that there's anything with Firefox that would be impossible or even more difficult to do on a lispm than e.g. linux. Other than the sheer amount of work required to implement a browser, that is. Firefox I believe can execute "internet code" either by running a downloaded executable, in which case all bets are off, or it can run something like javascript, flash, or java applets, all of which are examples of virtual machines that could be implemented on a lispm just as well as on linux. -- Frode V. Fjeld
From: Nicolas Neuss on 19 Jan 2010 08:25 "Frode V. Fjeld" <frode(a)netfonds.no> writes: > [...] Hello Frode, reading your post I thought about trying to run your Movitz. Could you maybe sketch a little bit how difficult this is? Are there images which can be run within some virtual machine? Nicolas
From: Helmut Eller on 19 Jan 2010 08:57 * Frode V. Fjeld [2010-01-19 13:54+0100] writes: > I don't know that there's anything with Firefox that would be impossible > or even more difficult to do on a lispm than e.g. linux. Other than the > sheer amount of work required to implement a browser, that is. Isolation? Unix uses the MMU to isolate process from each other. That makes it fairly safe to execute programs written in low level languages like C or assembler. The accessible memory is protected by the MMU and everything else must be done via syscalls. On the Lisp Machine every program had (intentionally) access to the whole machine. That simplified debugging. On the downside, a bug in one program could bring down the entire machine. In Unix terms, there was no distinction between user space and kernel space. Isolation also forced the Unix people to invent shared libraries so that at read-only data/code could be shared safely. Nothing like that existed on Lisp Machines, or does it? I would not want to use an OS that doesn't provide isolation. Helmut
From: Frode V. Fjeld on 19 Jan 2010 14:47
Nicolas Neuss <lastname(a)math.uni-karlsruhe.de> writes: > reading your post I thought about trying to run your Movitz. Could > you maybe sketch a little bit how difficult this is? Are there images > which can be run within some virtual machine? It shouldn't be difficult at all. There's an (somewhat old) image for download, which should load right into any x86 emulator. -- Frode V. Fjeld |