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From: nonsense on 11 Mar 2007 12:14 Eeyore wrote: > > "nonsense(a)unsettled.com" wrote: > > >>There's no good reason to have selected 5 volts as opposed >>to 6 volts, or for that matter, 8 volts. > > > Utter nonsense. > > The IC process used for TTL has a breakdown voltage of around 7 volts. The supply > voltage has to be less than that. > > Graham > Just when I thought dumb donkey had run out of stupid things to say.
From: nonsense on 11 Mar 2007 12:16 Ken Smith wrote: > In article <et0nu2$8qk_001(a)s776.apx1.sbo.ma.dialup.rcn.com>, > <jmfbahciv(a)aol.com> wrote: > >>In article <esuq2s$ds3$4(a)blue.rahul.net>, >> kensmith(a)green.rahul.net (Ken Smith) wrote: > > [....] > >>>has run on 5V. The selection of 5V can be traced in part to the heater >>>voltage on tubes. >> >>Now think about that over time. > > > Suddenly, you are arguing exactly my case and agreeing with me but putting > the above as a preface to it. This is a very strange thing for you to be > doing. I was the one arguing that a lot of choice are the result of > considerations that appeared trivial or near coin tosses at the time that > ended up having a large effect later. I used the 5V logic case because I > thought it was an obvious and well known example. From the fact that I > got an argument on it, I see that it is less well known than I thought. There are lots of well believed urban legends. >> The constraint was 5V so choices >>made from one development project to the next had to include >>the old choices. Most projects had to think about backwards >>compatibility and the parts and power that was available at the >>time of planning. Then implementation was also determined by >>the parts and resources available at the time of the implementation. >>You can't make something that depends on a foobar existing at >>the time of production. There is also the requirement that there >>will be enough of the foobars so manufacturing the item >>won't be held up.
From: Ken Smith on 11 Mar 2007 12:18 In article <et0qsp$8qk_002(a)s776.apx1.sbo.ma.dialup.rcn.com>, <jmfbahciv(a)aol.com> wrote: >In article <esurfc$ds3$6(a)blue.rahul.net>, > kensmith(a)green.rahul.net (Ken Smith) wrote: >>In article <esu74a$8qk_001(a)s861.apx1.sbo.ma.dialup.rcn.com>, >> <jmfbahciv(a)aol.com> wrote: >>>In article <esrtcj$qj4$1(a)blue.rahul.net>, >>> kensmith(a)green.rahul.net (Ken Smith) wrote: >>[....] >>>>In other words, you wrote the TAPE.DIR after all the other files were >>>>written. This means you had to write a file of that size and then the >>>>data and then open TAPE.DIR for writing. >>>> >>>>If this is what you did then my method of putting a correct checksum still >>>>works. If you wrote the TAPE.DIR before the other files and never changed >>>>it, my method still works. >>>> >>>> >>>>[....] >>>>>Anybody who has done any grocery shopping would know the difference >>>>>between the two. Just because dog food is on your shopping list >>>>>never guarantees that dog food will be in your car when you get home. >>>>>The only listing that shows you were successful in putting >>>>>dog food in the shopping cart is the cash register receipt. >>>> >>>>Does this mean you wrote TAPE.DIR after the other files were all written? >>> >>>Yes. TAPE.DIR was created after the files were written to the tape. >>>That is how you get a directory listing of the tape onto the tape. >>> >>>The first cut of the tape had a zero block TAPE.DIR for a place holder >>>on the tape. Then a DIRECT DSK:TAPE.DIR=TAPE:/CHECKSUM was done. >>>Then another save was done; this time TAPE.DIR that was on the >>>tape contained a checksummed directory of the tape. >> >>In other words, you "editted" the tape. > >No. How yes you did. You did exactly the action called editing when speaking of a tape. > >> You wrote one file and then wrote >>something different in its place. > >No. I wrote the whole save set. In magtape terms, the saveset >was the file on the tape. Now what the heck are you claiming? >I know you've explained ad nauseum. You keep ignoring the point >of the file. IOW, you implemented something that wasn't in the spec. >In fact, your implementation is 100% contrary to the spec. You seem to keep not being able to understand it, or the spec said "do it wrong". [....] >>As I explained, the claim that it can't be correct it wrong. The method I >>explained makes it correct. There is no problem. > >But you don't fulfill the requirement that the file is a >directory of the tape, untouched by editing hands. Yes, I do. At least if you are as you claimed earlier in the development team. [....] >>You don't seem to be able to understand the idea so yes, I guess you would >>punt the idea. leaving the tape incorrect and your customers at an extra >>risk. > >Nobody assembled the file called TAPE.DIR. It listed the files >that were on the tape when we made the master. You earlier stated a command you typed to make the file. Are you a noone?????? [....] >>No, it would not, You just need to think about what I really said. When >>you first made the tape, you left a gap for the file. > >No, there is no gap. > >> You then write this >>file after. Before you write this TAPE.DIR, you think for about 3 seconds >>and then write a TAPE.DIR that is completely correct instead of one with >>an error in it. > >You do not understand how tapes ROFLMAO You were the one that didn't know. >> This means it was not >>perfect at the instant you created it. The checksum was wrong because you >>didn't think for about 3 seconds. > >I thought about this problem for months before I decided that it >was OK to have one 36-bit word incorrect on that tape. I've thought >about the CATCH-22 problem often since then because those >are neat puzzles. You missed the obvious way to solve the problem. You thought it could not be solved, even though at that time, it was very likely solved in nearly every other shop on the planet. [....] >>This has nothing to do with the question at hand. The strips on the ends >>of tapes were moved on ones that were being used as scratch. You would >>never do this on a production tape. > >We had to do this on a master tape. You simply have no concept >of the problems in a manufacturing environment when the products >produced were OSes and the computers they were installed on. Your shop had flaky practices. That is all there is to it. [...] >>Yes it does! You can do exactly all the same steps as what you did plus a >>very small amount of thinking and get it right. > >No, it doesn't. Your method says what we think it should be like. >That is very different from what it really is like. No, you missed the whole point. My method makes it correct. That is correct in all the same ways as your method did plus the added one of not making a wrong checksum. You have missed the central point and gotten mixed up about what I was suggesting vs what I used in an example to try make it clear to you. Go back and reread. The example I did earlier or the one I did just a day ago. Look at how it worked. Understand that one little thing and then maybe the light will come on. [....] >>You wrote something onto the tape called TAPE.DIR. I have not suggested >>anything that makes its size change in anyway that you did not have. >>Either you knew before hand its size or you didn't. > >I didn't know because the magtape had not been made yet. So, you didn't know the size. The suggested method still works. There is no reason to ship tapes with an incorrect checksum. >> I assume you did >>because you had to write something to take up that much space. Nothing in >>what I suggested makes that any sort of a problem. > >The first TAPE.DIR on the tape was a zero block file. This is an interesting change to what you said earlier. If the TAPE.DIR was at the front of the tape and was not already the length needed, then you could not write the TAPE.DIR in its place. You had to: (1) Write a new tape. (2) Overwrite this tape. or (3) Not put the TAPE.DIR at the start. >>We are not talking about humans doing things we are talking about what >>computers could do. > >Humans made everything. Humans told the computers what to do. Squirm squirm. [....] >YOur method does not provide a directory of what is on the tape. >The whole point was to document what was on the tape when we made >it. Yes, it does. You haven't understood what it is. Until you stop assuming that I somehow didn't put the right things on the tape, you will not catch on. -- -- kensmith(a)rahul.net forging knowledge
From: MassiveProng on 11 Mar 2007 12:52 On Sun, 11 Mar 2007 15:57:08 +0000 (UTC), kensmith(a)green.rahul.net (Ken Smith) Gave us: >In article <et0nu2$8qk_001(a)s776.apx1.sbo.ma.dialup.rcn.com>, > <jmfbahciv(a)aol.com> wrote: >>In article <esuq2s$ds3$4(a)blue.rahul.net>, >> kensmith(a)green.rahul.net (Ken Smith) wrote: >[....] >>>has run on 5V. The selection of 5V can be traced in part to the heater >>>voltage on tubes. >> >>Now think about that over time. > >Suddenly, you are arguing exactly my case and agreeing with me but putting >the above as a preface to it. This is a very strange thing for you to be >doing. I was the one arguing that a lot of choice are the result of >considerations that appeared trivial or near coin tosses at the time that >ended up having a large effect later. I used the 5V logic case because I >thought it was an obvious and well known example. From the fact that I >got an argument on it, I see that it is less well known than I thought. > > >> The constraint was 5V so choices >>made from one development project to the next had to include >>the old choices. Most projects had to think about backwards >>compatibility and the parts and power that was available at the >>time of planning. Then implementation was also determined by >>the parts and resources available at the time of the implementation. >>You can't make something that depends on a foobar existing at >>the time of production. There is also the requirement that there >>will be enough of the foobars so manufacturing the item >>won't be held up. Remember the tiny, baby finger sized tubes of the 40s and 50s military radios by Raytheon and the like? What were their filament voltages? ISTR it being slightly lower than 6.3V, not certain though. Then, the TV era had tubes in the 3 to 6 inch length range. Filament voltage selection would seem to me to have at least a little to do with how far up a tube one could spiral a length of filament media and still get nice, even heating of it without adversely affecting longevity.
From: MassiveProng on 11 Mar 2007 12:53
On Sun, 11 Mar 2007 10:14:09 -0600, "nonsense(a)unsettled.com" <nonsense(a)unsettled.com> Gave us: >Eeyore wrote: >> >> "nonsense(a)unsettled.com" wrote: >> >> >>>There's no good reason to have selected 5 volts as opposed >>>to 6 volts, or for that matter, 8 volts. >> >> >> Utter nonsense. >> >> The IC process used for TTL has a breakdown voltage of around 7 volts. The supply >> voltage has to be less than that. >> >> Graham >> > >Just when I thought dumb donkey had run out of >stupid things to say. As if a twit like you knows anything about it. |