Jihad needs scientists
in [Design]
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From: nonsense on 20 Feb 2007 09:48 Ken Smith wrote: > In article <ereron$8qk_010(a)s883.apx1.sbo.ma.dialup.rcn.com>, > <jmfbahciv(a)aol.com> wrote: > [......] >>>The reason almost all PCs aren't dually is not because PCs >>>can't be dually, it's because that's what the market wants. >>That's not the reason. Devices aren't multi-ported. To have >>an effective multi-CPU general purpose system, all CPUs should >>have hardware access to all devices. > That is not true. You can have single ported devices in a multiprocessor > system with no problem. Since the device is usually a physical thing, it > can only do one thing at a time and is always slower than the processor. > A well written OS can deal with this issue with no big problem. >> Another limitation is >>no PC systems are sold that can have multiple ttys connected to it. > The PC I'm typing on can have 2 ttys connected. The one at work can have > 4. This isn't the real problem. I have one here running Linux that's probably only LAN limited. Today's TTY is often a PC but you might want to take a look at http://www.wyse.com/index.asp >>>Those who strive for more than mediocrity in their PC have >>>been able to find duallies quite easily for a decade. >>But are the device drivers reentrant? If they aren't, the >>multi-CPU systems aren't as useful as they could be. > Reentrant drivers are not the issue when the hardware they connect to > isn't. A well written OS will deal with it by letting one or the other > CPU have control of the device while its operations are going on and make > sure the other CPU is doing something elese useful.
From: Ken Smith on 20 Feb 2007 09:56 In article <erergj$8qk_009(a)s883.apx1.sbo.ma.dialup.rcn.com>, <jmfbahciv(a)aol.com> wrote: >In article <ercn84$8qv$2(a)blue.rahul.net>, > kensmith(a)green.rahul.net (Ken Smith) wrote: [....] >>No, I know when to be paranoid. The [BP+N] is a waste of a single noid. > >ROTFL. Not in my work. I used make byte pointers on the fly >all the time. This is a bit x86 specific: Spend your time on the [BP+SI] type pointers these are the ones that let you take control of the OS (whether you want to or not). When a buffer on the stack overflows, the return address can be overwritten. When the routine returns, it jumps to whatever address is there. If you cause a buffer overflow in OS level code and place your codes address in there, you become the OS. To protect against this you have to bounds check your accesses to the arrays on the stack. Because the return address is between the passed parameters and the local variables, it can get it from either side. On some processors, there was a hardware protection that would prevent the corruption. The IBM 360 and 370 were completely immune to all attacks that involved the stack. -- -- kensmith(a)rahul.net forging knowledge
From: Ken Smith on 20 Feb 2007 10:04 In article <erennl$8ss_006(a)s883.apx1.sbo.ma.dialup.rcn.com>, <jmfbahciv(a)aol.com> wrote: >In article <ercoj7$8qv$4(a)blue.rahul.net>, > kensmith(a)green.rahul.net (Ken Smith) wrote: >>In article <ercbpb$8qk_009(a)s942.apx1.sbo.ma.dialup.rcn.com>, >> <jmfbahciv(a)aol.com> wrote: >>[.. surf web, get spam and play games ..] >>>>Go take a look at what all those PCs get used for. What I listed was most >>>>of it. People have PCs in there home that only serve as a very limited >>>>tool. >>> >>>Nope. I'm currently running a test so see just how much pressure >>>people are getting to start doing on-line banking. The latest >>>development is that any check you write is handled like a debit >>>card. The requirement for a voucher for each payment is disappearing. >> >>You are one person and certainly the minority. I'm about to look at what >>my wife is doing on her computer..... >> >>She is "surfing the web" right now. Like many others. >> >>Just because a few people do more complex stuff, you can't assume that >>everyone does. > >This isn't an assumption. There is enormous pressure to herd >the general public into using electronic banking. I use electronic banking. I go to the banks web site and do it. It is just another "surfing the web" case. I don't have any special software to do it. I am far from the normal user but even I didn't add anything beyond the web browser to do my banking. -- -- kensmith(a)rahul.net forging knowledge
From: Ken Smith on 20 Feb 2007 10:05 In article <ereo6m$8ss_009(a)s883.apx1.sbo.ma.dialup.rcn.com>, <jmfbahciv(a)aol.com> wrote: >In article <87irdym3zz.fsf(a)nonospaz.fatphil.org>, > Phil Carmody <thefatphil_demunged(a)yahoo.co.uk> wrote: >>Eeyore <rabbitsfriendsandrelations(a)hotmail.com> writes: >>> MassiveProng wrote: >>> >>> > I can boot Linux from a DVD and RUN it all day long, and I don't need to >do >>> > ANY installation! >>> >>> That sounds interesting. >>> >>> Where can I get one ? >> >>Ubuntu, Kubuntu, Xubuntu all come as live CDs >>Gentoo does too. >>Knoppix was the original popular live CD. > >What does the OS, running from a CD, use for its scratch pad? ><snip> It uses the RAM of the computer. They like to have quite a lot of RAM. -- -- kensmith(a)rahul.net forging knowledge
From: Ken Smith on 20 Feb 2007 10:07
In article <ereo06$8ss_008(a)s883.apx1.sbo.ma.dialup.rcn.com>, <jmfbahciv(a)aol.com> wrote: >In article <66a0f$45d9e1db$4fe709e$21351(a)DIALUPUSA.NET>, > "nonsense(a)unsettled.com" <nonsense(a)unsettled.com> wrote: [.....] >>just to see where that one goes. It is an issue I've not >>seen addressed. It gets even more interesting when viewed >>through the prisms of the various physics models in use >>today. > >Analog implies thresholds; does it not? No, it doesn't. It implies a continuous function. This isn't always true. -- -- kensmith(a)rahul.net forging knowledge |