Forums

LTC Switcher CAD3 ?

Started by Robert Baer June 2, 2012
On Jun 5, 3:18=A0am, Jamie
<jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote:
> BillSlomanwrote: > > On Jun 4, 8:44 pm, Jamie > > <jamie_ka1lpa_not_valid_after_ka1l...@charter.net> wrote: > > >>Fred Abse wrote: > > >>>On Mon, 04 Jun 2012 00:28:55 -0700,BillSlomanwrote: > > >>>>You are right, and the units ought to Henry per turn^-2 > > >>>Contradicts what Phil, Tim, John, and I all seem to agree on. > > >>>Henry per turn^2. Lose the minus. > > >>>Being of a charitable disposition, I'll put it down to the lateness of=
the
> >>>hour ;-) > > >>He lives in a negative world! It's natural for him. > > > Jamie gets it wrong - as usual. > > > =A0 The only thing I did wrong was acknowledging your existence here.
The usual failure of perception. -- Bill Sloman, Nijmegen
On Jun 5, 3:48=A0am, "Tim Williams" <tmoran...@charter.net> wrote:
> "BillSloman" <bill.slo...@ieee.org> wrote in message > > news:798e6541-19e0-4e08-a11d-c774ce0777ee@fr28g2000vbb.googlegroups.com..=
.
> > >On Jun 4, 6:17 pm, Fred Abse <excretatau...@invalid.invalid> wrote: > >> On Mon, 04 Jun 2012 00:28:55 -0700,BillSlomanwrote: > >> > You are right, and the units ought to Henry per turn^-2 > ... > >so the dimensions of Al are Henries. turns^-2. > > Bill: "per" means "divided by".
Oops. Agreed. -- Bill Sloman, Nijmegen
On Jun 4, 6:31=A0pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Mon, 4 Jun 2012 08:51:29 -0700 (PDT),BillSloman > > > > > > > > > > <bill.slo...@ieee.org> wrote: > >On Jun 4, 4:09 pm, John Larkin > ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: > >> On Mon, 4 Jun 2012 00:34:20 -0700 (PDT),BillSloman > > >> <bill.slo...@ieee.org> wrote: > >> >On Jun 4, 6:00 am, John Larkin > >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: > >> >> On Sun, 3 Jun 2012 17:58:36 -0700 (PDT),BillSloman > > >> >> <bill.slo...@ieee.org> wrote: > >> >> >On Jun 3, 10:09 pm, Phil Hobbs > >> >> ><pcdhSpamMeSensel...@electrooptical.net> wrote: > >> >> >>BillSlomanwrote: > > >> >> >> > On Jun 3, 9:02 pm, Fred Abse <excretatau...@invalid.invalid> w=
rote:
> >> >> >> > > On Sun, 03 Jun 2012 05:11:52 -0700,BillSlomanwrote: > >> >> >> > > > We've just measured a coupling of 0.98 in a gapped RM14 co=
re - EPCOS
> >> >> >> > > > gapped it down from 6000uH/root turn for an ungapped pair =
to 630nH per
> >> >> >> > > > root turn by grinding back the centre pillar by 0.4mm, > > >> >> >> > > I think that should be "per turn squared". > > >> >> >> > Wrong. Inductance is proportional to the square of the number =
of
> >> >> >> > turns, as long as they are closely coupled. > > >> >> >> >http://en.wikipedia.org/wiki/Inductor > > >> >> >> If L =3D alpha * N**2, then alpha has units of henries per turn =
squared.
> >> >> >> (Of course a turn isn't really a unit, just as a radian and a st=
eradian
> >> >> >> aren't, but it sure isn't per square root turn.) > > >> >> >Applying dimensional analysis to a manufacturer's design fudge fac=
tor
> >> >> >is the sort of thing that physicists do. > > >> >> Engineers, too. My first engineering course at Tulane, first semist=
er
> >> >> freshman year, was an introduction to units and dimensional analysi=
s.
> >> >> It was taught by Dr Johnson, the Dean of the Engineering School, wh=
o
> >> >> thought it was important. > > >> >> Random noise increases as the square root of bandwidth, so we speci=
fy
> >> >> it as volts per root Hz. > > >> >> Inductance increases with turns squared, so we spec a core Al as > >> >> henries per turn squared. > > >> >> See the difference? > > >> >It's 9:30am and my brain is working again, so yes - I do. > > >> Did you PWBC, post without benefit of coffee? I'm doing that now, and > >> it's a great hazard. > > >> >> >It's not a particularly useful activity. Reminding junior engineer=
s at
> >> >> >every possible opportunity that inductance is proportional to the > >> >> >square of the number of turns in a winding is an extremely useful > >> >> >activity, and saves loads of time at design reviews. > > >> >> They were probably polite enough to laugh at you after you left the > >> >> room. > > >> >Perhaps. But they'd got the point - attention-getting devices don't > >> >have to be pedantically correct to work. Look at Howard Johnson on > >> >high speed signal propagation. > > >> He's as dangerous as Professor Moriarty. > > >I don't know about dangerous, but pedagogically horrible. If you > >compare the lucid exposition of practical physics you get in Ralph > >Morrison's "Grounding and Shielding Techniques in Instrumentation" > > >http://www.amazon.com/Grounding-Shielding-Techniques-Ralph-Morrison/d... > > >with the incoherent messes that Howard Johnson peddles,you go from the > >sublime to the despicable. > > Yup. It's painful to read, even in the parts where he's technically > correct. > > > > >> (Incidentally, the latest "Sherlock" was stunning.) > > >You mean the BBC televison series? We've been watching it here - we > >get BBC 1 and 2 on the local cable - and liked it a lot. > > There are two running here now. The "classic" with Jeremy Brett, > pretty good, and the modern-day one. It's the new one that I was > referring to. I read all the Sherlocks several times when I was a kid, > and revisit them now and then for a quick read.
That makes you a Holmesian, rather than a Sherlock fan. I've just re- read Julina Barnes' "Arthur and George" http://www.guardian.co.uk/books/2005/jun/26/fiction.shopping which is essentially a portrait of Arthur Conan Doyle - a second rate author, who didn't recognise Holmes as his greatest creation. David Lodge does the English author biography a whole lot better. "Author, Author" about Henry James, and "A Man of Parts" about H.G.Wells, are both substantially better, perhaps because the subjects had a bit more to offer. -- Bill Sloman, Nijmegen
On Mon, 4 Jun 2012 23:09:42 -0700 (PDT), Bill Sloman
<bill.sloman@ieee.org> wrote:

>On Jun 4, 6:31&#2013266080;pm, John Larkin ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> On Mon, 4 Jun 2012 08:51:29 -0700 (PDT),BillSloman >> >> >> >> >> >> >> >> >> >> <bill.slo...@ieee.org> wrote: >> >On Jun 4, 4:09 pm, John Larkin >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> On Mon, 4 Jun 2012 00:34:20 -0700 (PDT),BillSloman >> >> >> <bill.slo...@ieee.org> wrote: >> >> >On Jun 4, 6:00 am, John Larkin >> >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> >> On Sun, 3 Jun 2012 17:58:36 -0700 (PDT),BillSloman >> >> >> >> <bill.slo...@ieee.org> wrote: >> >> >> >On Jun 3, 10:09 pm, Phil Hobbs >> >> >> ><pcdhSpamMeSensel...@electrooptical.net> wrote: >> >> >> >>BillSlomanwrote: >> >> >> >> >> > On Jun 3, 9:02 pm, Fred Abse <excretatau...@invalid.invalid> wrote: >> >> >> >> > > On Sun, 03 Jun 2012 05:11:52 -0700,BillSlomanwrote: >> >> >> >> > > > We've just measured a coupling of 0.98 in a gapped RM14 core - EPCOS >> >> >> >> > > > gapped it down from 6000uH/root turn for an ungapped pair to 630nH per >> >> >> >> > > > root turn by grinding back the centre pillar by 0.4mm, >> >> >> >> >> > > I think that should be "per turn squared". >> >> >> >> >> > Wrong. Inductance is proportional to the square of the number of >> >> >> >> > turns, as long as they are closely coupled. >> >> >> >> >> >http://en.wikipedia.org/wiki/Inductor >> >> >> >> >> If L = alpha * N**2, then alpha has units of henries per turn squared. >> >> >> >> (Of course a turn isn't really a unit, just as a radian and a steradian >> >> >> >> aren't, but it sure isn't per square root turn.) >> >> >> >> >Applying dimensional analysis to a manufacturer's design fudge factor >> >> >> >is the sort of thing that physicists do. >> >> >> >> Engineers, too. My first engineering course at Tulane, first semister >> >> >> freshman year, was an introduction to units and dimensional analysis. >> >> >> It was taught by Dr Johnson, the Dean of the Engineering School, who >> >> >> thought it was important. >> >> >> >> Random noise increases as the square root of bandwidth, so we specify >> >> >> it as volts per root Hz. >> >> >> >> Inductance increases with turns squared, so we spec a core Al as >> >> >> henries per turn squared. >> >> >> >> See the difference? >> >> >> >It's 9:30am and my brain is working again, so yes - I do. >> >> >> Did you PWBC, post without benefit of coffee? I'm doing that now, and >> >> it's a great hazard. >> >> >> >> >It's not a particularly useful activity. Reminding junior engineers at >> >> >> >every possible opportunity that inductance is proportional to the >> >> >> >square of the number of turns in a winding is an extremely useful >> >> >> >activity, and saves loads of time at design reviews. >> >> >> >> They were probably polite enough to laugh at you after you left the >> >> >> room. >> >> >> >Perhaps. But they'd got the point - attention-getting devices don't >> >> >have to be pedantically correct to work. Look at Howard Johnson on >> >> >high speed signal propagation. >> >> >> He's as dangerous as Professor Moriarty. >> >> >I don't know about dangerous, but pedagogically horrible. If you >> >compare the lucid exposition of practical physics you get in Ralph >> >Morrison's "Grounding and Shielding Techniques in Instrumentation" >> >> >http://www.amazon.com/Grounding-Shielding-Techniques-Ralph-Morrison/d... >> >> >with the incoherent messes that Howard Johnson peddles,you go from the >> >sublime to the despicable. >> >> Yup. It's painful to read, even in the parts where he's technically >> correct. >> >> >> >> >> (Incidentally, the latest "Sherlock" was stunning.) >> >> >You mean the BBC televison series? We've been watching it here - we >> >get BBC 1 and 2 on the local cable - and liked it a lot. >> >> There are two running here now. The "classic" with Jeremy Brett, >> pretty good, and the modern-day one. It's the new one that I was >> referring to. I read all the Sherlocks several times when I was a kid, >> and revisit them now and then for a quick read. > >That makes you a Holmesian, rather than a Sherlock fan. I've just re- >read Julina Barnes' "Arthur and George" > >http://www.guardian.co.uk/books/2005/jun/26/fiction.shopping > >which is essentially a portrait of Arthur Conan Doyle - a second rate >author, who didn't recognise Holmes as his greatest creation.
He claimed to have written one story during a break in a cricket game, and killed him off because he was bored with him.
> >David Lodge does the English author biography a whole lot better. >"Author, Author" about Henry James, and "A Man of Parts" about >H.G.Wells, are both substantially better, perhaps because the subjects >had a bit more to offer.
I can't read either of them, for some reason. HJ is especially boring to me... I've never made it halway through any of his books. But I can, and do, reread the better Jane Austens and PG Wodehouses regularly. I'm now reading Enigma, the Turing biography. It's amazing the ideas that had about computers in about 1950. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
On Jun 5, 4:16=A0pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Mon, 4 Jun 2012 23:09:42 -0700 (PDT),BillSloman > > <bill.slo...@ieee.org> wrote: > >On Jun 4, 6:31=A0pm, John Larkin > ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: > >> On Mon, 4 Jun 2012 08:51:29 -0700 (PDT),BillSloman > > >> <bill.slo...@ieee.org> wrote: > >> >On Jun 4, 4:09 pm, John Larkin > >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: > >> >> On Mon, 4 Jun 2012 00:34:20 -0700 (PDT),BillSloman > > >> >> <bill.slo...@ieee.org> wrote: > >> >> >On Jun 4, 6:00 am, John Larkin > >> >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: > >> >> >> On Sun, 3 Jun 2012 17:58:36 -0700 (PDT),BillSloman > > >> >> >> <bill.slo...@ieee.org> wrote: > >> >> >> >On Jun 3, 10:09 pm, Phil Hobbs > >> >> >> ><pcdhSpamMeSensel...@electrooptical.net> wrote: > >> >> >> >>BillSlomanwrote: > > >> >> >> >> > On Jun 3, 9:02 pm, Fred Abse <excretatau...@invalid.invalid= > wrote: > >> >> >> >> > > On Sun, 03 Jun 2012 05:11:52 -0700,BillSlomanwrote: > >> >> >> >> > > > We've just measured a coupling of 0.98 in a gapped RM14=
core - EPCOS
> >> >> >> >> > > > gapped it down from 6000uH/root turn for an ungapped pa=
ir to 630nH per
> >> >> >> >> > > > root turn by grinding back the centre pillar by 0.4mm, > > >> >> >> >> > > I think that should be "per turn squared". > > >> >> >> >> > Wrong. Inductance is proportional to the square of the numb=
er of
> >> >> >> >> > turns, as long as they are closely coupled. > > >> >> >> >> >http://en.wikipedia.org/wiki/Inductor > > >> >> >> >> If L =3D alpha * N**2, then alpha has units of henries per tu=
rn squared.
> >> >> >> >> (Of course a turn isn't really a unit, just as a radian and a=
steradian
> >> >> >> >> aren't, but it sure isn't per square root turn.) > > >> >> >> >Applying dimensional analysis to a manufacturer's design fudge =
factor
> >> >> >> >is the sort of thing that physicists do. > > >> >> >> Engineers, too. My first engineering course at Tulane, first sem=
ister
> >> >> >> freshman year, was an introduction to units and dimensional anal=
ysis.
> >> >> >> It was taught by Dr Johnson, the Dean of the Engineering School,=
who
> >> >> >> thought it was important. > > >> >> >> Random noise increases as the square root of bandwidth, so we sp=
ecify
> >> >> >> it as volts per root Hz. > > >> >> >> Inductance increases with turns squared, so we spec a core Al as > >> >> >> henries per turn squared. > > >> >> >> See the difference? > > >> >> >It's 9:30am and my brain is working again, so yes - I do. > > >> >> Did you PWBC, post without benefit of coffee? I'm doing that now, a=
nd
> >> >> it's a great hazard. > > >> >> >> >It's not a particularly useful activity. Reminding junior engin=
eers at
> >> >> >> >every possible opportunity that inductance is proportional to t=
he
> >> >> >> >square of the number of turns in a winding is an extremely usef=
ul
> >> >> >> >activity, and saves loads of time at design reviews. > > >> >> >> They were probably polite enough to laugh at you after you left =
the
> >> >> >> room. > > >> >> >Perhaps. But they'd got the point - attention-getting devices don'=
t
> >> >> >have to be pedantically correct to work. Look at Howard Johnson on > >> >> >high speed signal propagation. > > >> >> He's as dangerous as Professor Moriarty. > > >> >I don't know about dangerous, but pedagogically horrible. If you > >> >compare the lucid exposition of practical physics you get in Ralph > >> >Morrison's "Grounding and Shielding Techniques in Instrumentation" > > >> >http://www.amazon.com/Grounding-Shielding-Techniques-Ralph-Morrison/d=
...
> > >> >with the incoherent messes that Howard Johnson peddles,you go from th=
e
> >> >sublime to the despicable. > > >> Yup. It's painful to read, even in the parts where he's technically > >> correct. > > >> >> (Incidentally, the latest "Sherlock" was stunning.) > > >> >You mean the BBC televison series? We've been watching it here - we > >> >get BBC 1 and 2 on the local cable - and liked it a lot. > > >> There are two running here now. The "classic" with Jeremy Brett, > >> pretty good, and the modern-day one. It's the new one that I was > >> referring to. I read all the Sherlocks several times when I was a kid, > >> and revisit them now and then for a quick read. > > >That makes you a Holmesian, rather than a Sherlock fan. I've just re- > >read Julina Barnes' "Arthur and George" > > >http://www.guardian.co.uk/books/2005/jun/26/fiction.shopping > > >which is essentially a portrait of Arthur Conan Doyle - a second rate > >author, who didn't recognise Holmes as his greatest creation. > > He claimed to have written one story during a break in a cricket game, > and killed him off because he was bored with him. > > >David Lodge does the English author biography a whole lot better. > >"Author, Author" about Henry James, and "A Man of Parts" about > >H.G.Wells, are both substantially better, perhaps because the subjects > >had a bit more to offer. > > I can't read either of them, for some reason. HJ is especially boring > to me...
I can't read his novels - nothing ever happens. He wrote a few science- fiction short stories in the sytle of H.G.Wells (who was a friend of his) which aren't too bad. H.G.Wells was also a second rate novelist. His science fiction is interesting - the ideas are sufficiently interesting to transcend his defects as a novelist - if somewhat half-baked. His ideas about the shape of things to come weren't all that accurate, but his expectation that technological innovation would change the way we live was useful.
> I've never made it halfway through any of his books. But I > can, and do, reread the better Jane Austens and PG Wodehouses > regularly.
Jane Austen is well worth rereading. P G Wodehouse isn't - anything that Wodehouse could do, Terry Pratchett can do better. Terry Pratchett is a lot better educated than Wodehouse was, and it shows.
> I'm now reading Enigma, the Turing biography. It's amazing the ideas > that they had about computers in about 1950.
Read old copies of Astounding Science Fiction - around 1950 - for really bizarre ideas about computers. -- Bill Sloman, Nijmegen
On Mon, 04 Jun 2012 09:31:24 -0700, John Larkin wrote:

> There are two running here now. The "classic" with Jeremy Brett, pretty > good, and the modern-day one. It's the new one that I was referring to. I > read all the Sherlocks several times when I was a kid, and revisit them > now and then for a quick read.
I think the Jeremy Brett series the best, especially those with Edward Hardwicke as Watson, although the portrayal of Mycroft is a bit over-the-top for my taste. -- "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." (Richard Feynman)
On Tue, 5 Jun 2012 07:48:12 -0700 (PDT), Bill Sloman
<bill.sloman@ieee.org> wrote:

>On Jun 5, 4:16&#2013266080;pm, John Larkin ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> On Mon, 4 Jun 2012 23:09:42 -0700 (PDT),BillSloman >> >> <bill.slo...@ieee.org> wrote: >> >On Jun 4, 6:31&#2013266080;pm, John Larkin >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> On Mon, 4 Jun 2012 08:51:29 -0700 (PDT),BillSloman >> >> >> <bill.slo...@ieee.org> wrote: >> >> >On Jun 4, 4:09 pm, John Larkin >> >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> >> On Mon, 4 Jun 2012 00:34:20 -0700 (PDT),BillSloman >> >> >> >> <bill.slo...@ieee.org> wrote: >> >> >> >On Jun 4, 6:00 am, John Larkin >> >> >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> >> >> On Sun, 3 Jun 2012 17:58:36 -0700 (PDT),BillSloman >> >> >> >> >> <bill.slo...@ieee.org> wrote: >> >> >> >> >On Jun 3, 10:09 pm, Phil Hobbs >> >> >> >> ><pcdhSpamMeSensel...@electrooptical.net> wrote: >> >> >> >> >>BillSlomanwrote: >> >> >> >> >> >> > On Jun 3, 9:02 pm, Fred Abse <excretatau...@invalid.invalid> wrote: >> >> >> >> >> > > On Sun, 03 Jun 2012 05:11:52 -0700,BillSlomanwrote: >> >> >> >> >> > > > We've just measured a coupling of 0.98 in a gapped RM14 core - EPCOS >> >> >> >> >> > > > gapped it down from 6000uH/root turn for an ungapped pair to 630nH per >> >> >> >> >> > > > root turn by grinding back the centre pillar by 0.4mm, >> >> >> >> >> >> > > I think that should be "per turn squared". >> >> >> >> >> >> > Wrong. Inductance is proportional to the square of the number of >> >> >> >> >> > turns, as long as they are closely coupled. >> >> >> >> >> >> >http://en.wikipedia.org/wiki/Inductor >> >> >> >> >> >> If L = alpha * N**2, then alpha has units of henries per turn squared. >> >> >> >> >> (Of course a turn isn't really a unit, just as a radian and a steradian >> >> >> >> >> aren't, but it sure isn't per square root turn.) >> >> >> >> >> >Applying dimensional analysis to a manufacturer's design fudge factor >> >> >> >> >is the sort of thing that physicists do. >> >> >> >> >> Engineers, too. My first engineering course at Tulane, first semister >> >> >> >> freshman year, was an introduction to units and dimensional analysis. >> >> >> >> It was taught by Dr Johnson, the Dean of the Engineering School, who >> >> >> >> thought it was important. >> >> >> >> >> Random noise increases as the square root of bandwidth, so we specify >> >> >> >> it as volts per root Hz. >> >> >> >> >> Inductance increases with turns squared, so we spec a core Al as >> >> >> >> henries per turn squared. >> >> >> >> >> See the difference? >> >> >> >> >It's 9:30am and my brain is working again, so yes - I do. >> >> >> >> Did you PWBC, post without benefit of coffee? I'm doing that now, and >> >> >> it's a great hazard. >> >> >> >> >> >It's not a particularly useful activity. Reminding junior engineers at >> >> >> >> >every possible opportunity that inductance is proportional to the >> >> >> >> >square of the number of turns in a winding is an extremely useful >> >> >> >> >activity, and saves loads of time at design reviews. >> >> >> >> >> They were probably polite enough to laugh at you after you left the >> >> >> >> room. >> >> >> >> >Perhaps. But they'd got the point - attention-getting devices don't >> >> >> >have to be pedantically correct to work. Look at Howard Johnson on >> >> >> >high speed signal propagation. >> >> >> >> He's as dangerous as Professor Moriarty. >> >> >> >I don't know about dangerous, but pedagogically horrible. If you >> >> >compare the lucid exposition of practical physics you get in Ralph >> >> >Morrison's "Grounding and Shielding Techniques in Instrumentation" >> >> >> >http://www.amazon.com/Grounding-Shielding-Techniques-Ralph-Morrison/d... >> >> >> >with the incoherent messes that Howard Johnson peddles,you go from the >> >> >sublime to the despicable. >> >> >> Yup. It's painful to read, even in the parts where he's technically >> >> correct. >> >> >> >> (Incidentally, the latest "Sherlock" was stunning.) >> >> >> >You mean the BBC televison series? We've been watching it here - we >> >> >get BBC 1 and 2 on the local cable - and liked it a lot. >> >> >> There are two running here now. The "classic" with Jeremy Brett, >> >> pretty good, and the modern-day one. It's the new one that I was >> >> referring to. I read all the Sherlocks several times when I was a kid, >> >> and revisit them now and then for a quick read. >> >> >That makes you a Holmesian, rather than a Sherlock fan. I've just re- >> >read Julina Barnes' "Arthur and George" >> >> >http://www.guardian.co.uk/books/2005/jun/26/fiction.shopping >> >> >which is essentially a portrait of Arthur Conan Doyle - a second rate >> >author, who didn't recognise Holmes as his greatest creation. >> >> He claimed to have written one story during a break in a cricket game, >> and killed him off because he was bored with him. >> >> >David Lodge does the English author biography a whole lot better. >> >"Author, Author" about Henry James, and "A Man of Parts" about >> >H.G.Wells, are both substantially better, perhaps because the subjects >> >had a bit more to offer. >> >> I can't read either of them, for some reason. HJ is especially boring >> to me... > >I can't read his novels - nothing ever happens. He wrote a few science- >fiction short stories in the sytle of H.G.Wells (who was a friend of >his) which aren't too bad. > >H.G.Wells was also a second rate novelist. His science fiction is >interesting - the ideas are sufficiently interesting to transcend his >defects as a novelist - if somewhat half-baked. His ideas about the >shape of things to come weren't all that accurate, but his expectation >that technological innovation would change the way we live was useful. > >> I've never made it halfway through any of his books. But I >> can, and do, reread the better Jane Austens and PG Wodehouses >> regularly. > >Jane Austen is well worth rereading. P G Wodehouse isn't - anything >that Wodehouse could do, Terry Pratchett can do better. Terry >Pratchett is a lot better educated than Wodehouse was, and it shows. > >> I'm now reading Enigma, the Turing biography. It's amazing the ideas >> that they had about computers in about 1950. > >Read old copies of Astounding Science Fiction - around 1950 - for >really bizarre ideas about computers.
I have "IBM's Early Computers" and some stuff like that. The current concept of a base-2 synchronous-state-machine Von Neumann architecture seems so obvious now, but it sure wasn't in the early days. At least Turing appreciated that binary-decimal conversion could be done in software. Maybe we should have stuck with the Harvard architecture. Microsoft has never learned the difference between code and data. It would be interesting to consider what sort of computer could be built with early 1950s-sort of technology. Say, a few thousand dual triodes and core memory. -- John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom timing and laser controllers Photonics and fiberoptic TTL data links VME analog, thermocouple, LVDT, synchro, tachometer Multichannel arbitrary waveform generators
On Jun 5, 5:55=A0pm, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
> On Tue, 5 Jun 2012 07:48:12 -0700 (PDT),BillSloman > > > > > > > > > > <bill.slo...@ieee.org> wrote: > >On Jun 5, 4:16 pm, John Larkin > ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: > >> On Mon, 4 Jun 2012 23:09:42 -0700 (PDT),BillSloman > > >> <bill.slo...@ieee.org> wrote: > >> >On Jun 4, 6:31 pm, John Larkin > >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: > >> >> On Mon, 4 Jun 2012 08:51:29 -0700 (PDT),BillSloman > > >> >> <bill.slo...@ieee.org> wrote: > >> >> >On Jun 4, 4:09 pm, John Larkin > >> >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: > >> >> >> On Mon, 4 Jun 2012 00:34:20 -0700 (PDT),BillSloman > > >> >> >> <bill.slo...@ieee.org> wrote: > >> >> >> >On Jun 4, 6:00 am, John Larkin > >> >> >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: > >> >> >> >> On Sun, 3 Jun 2012 17:58:36 -0700 (PDT),BillSloman > > >> >> >> >> <bill.slo...@ieee.org> wrote: > >> >> >> >> >On Jun 3, 10:09 pm, Phil Hobbs > >> >> >> >> ><pcdhSpamMeSensel...@electrooptical.net> wrote: > >> >> >> >> >>BillSlomanwrote: > > >> >> >> >> >> > On Jun 3, 9:02 pm, Fred Abse <excretatau...@invalid.inva=
lid> wrote:
> >> >> >> >> >> > > On Sun, 03 Jun 2012 05:11:52 -0700,BillSlomanwrote: > >> >> >> >> >> > > > We've just measured a coupling of 0.98 in a gapped R=
M14 core - EPCOS
> >> >> >> >> >> > > > gapped it down from 6000uH/root turn for an ungapped=
pair to 630nH per
> >> >> >> >> >> > > > root turn by grinding back the centre pillar by 0.4m=
m,
> > >> >> >> >> >> > > I think that should be "per turn squared". > > >> >> >> >> >> > Wrong. Inductance is proportional to the square of the n=
umber of
> >> >> >> >> >> > turns, as long as they are closely coupled. > > >> >> >> >> >> >http://en.wikipedia.org/wiki/Inductor > > >> >> >> >> >> If L =3D alpha * N**2, then alpha has units of henries per=
turn squared.
> >> >> >> >> >> (Of course a turn isn't really a unit, just as a radian an=
d a steradian
> >> >> >> >> >> aren't, but it sure isn't per square root turn.) > > >> >> >> >> >Applying dimensional analysis to a manufacturer's design fud=
ge factor
> >> >> >> >> >is the sort of thing that physicists do. > > >> >> >> >> Engineers, too. My first engineering course at Tulane, first =
semister
> >> >> >> >> freshman year, was an introduction to units and dimensional a=
nalysis.
> >> >> >> >> It was taught by Dr Johnson, the Dean of the Engineering Scho=
ol, who
> >> >> >> >> thought it was important. > > >> >> >> >> Random noise increases as the square root of bandwidth, so we=
specify
> >> >> >> >> it as volts per root Hz. > > >> >> >> >> Inductance increases with turns squared, so we spec a core Al=
as
> >> >> >> >> henries per turn squared. > > >> >> >> >> See the difference? > > >> >> >> >It's 9:30am and my brain is working again, so yes - I do. > > >> >> >> Did you PWBC, post without benefit of coffee? I'm doing that now=
, and
> >> >> >> it's a great hazard. > > >> >> >> >> >It's not a particularly useful activity. Reminding junior en=
gineers at
> >> >> >> >> >every possible opportunity that inductance is proportional t=
o the
> >> >> >> >> >square of the number of turns in a winding is an extremely u=
seful
> >> >> >> >> >activity, and saves loads of time at design reviews. > > >> >> >> >> They were probably polite enough to laugh at you after you le=
ft the
> >> >> >> >> room. > > >> >> >> >Perhaps. But they'd got the point - attention-getting devices d=
on't
> >> >> >> >have to be pedantically correct to work. Look at Howard Johnson=
on
> >> >> >> >high speed signal propagation. > > >> >> >> He's as dangerous as Professor Moriarty. > > >> >> >I don't know about dangerous, but pedagogically horrible. If you > >> >> >compare the lucid exposition of practical physics you get in Ralph > >> >> >Morrison's "Grounding and Shielding Techniques in Instrumentation" > > >> >> >http://www.amazon.com/Grounding-Shielding-Techniques-Ralph-Morriso=
n/d...
> > >> >> >with the incoherent messes that Howard Johnson peddles,you go from=
the
> >> >> >sublime to the despicable. > > >> >> Yup. It's painful to read, even in the parts where he's technically > >> >> correct. > > >> >> >> (Incidentally, the latest "Sherlock" was stunning.) > > >> >> >You mean the BBC televison series? We've been watching it here - w=
e
> >> >> >get BBC 1 and 2 on the local cable - and liked it a lot. > > >> >> There are two running here now. The "classic" with Jeremy Brett, > >> >> pretty good, and the modern-day one. It's the new one that I was > >> >> referring to. I read all the Sherlocks several times when I was a k=
id,
> >> >> and revisit them now and then for a quick read. > > >> >That makes you a Holmesian, rather than a Sherlock fan. I've just re- > >> >read Julina Barnes' "Arthur and George" > > >> >http://www.guardian.co.uk/books/2005/jun/26/fiction.shopping > > >> >which is essentially a portrait of Arthur Conan Doyle - a second rate > >> >author, who didn't recognise Holmes as his greatest creation. > > >> He claimed to have written one story during a break in a cricket game, > >> and killed him off because he was bored with him. > > >> >David Lodge does the English author biography a whole lot better. > >> >"Author, Author" about Henry James, and "A Man of Parts" about > >> >H.G.Wells, are both substantially better, perhaps because the subject=
s
> >> >had a bit more to offer. > > >> I can't read either of them, for some reason. HJ is especially boring > >> to me... > > >I can't read his novels - nothing ever happens. He wrote a few science- > >fiction short stories in the sytle of H.G.Wells (who was a friend of > >his) which aren't too bad. > > >H.G.Wells was also a second rate novelist. His science fiction is > >interesting - the ideas are sufficiently interesting to transcend his > >defects as a novelist - if somewhat half-baked. His ideas about the > >shape of things to come weren't all that accurate, but his expectation > >that technological innovation would change the way we live was useful. > > >> I've never made it halfway through any of his books. But I > >> can, and do, reread the better Jane Austens and PG Wodehouses > >> regularly. > > >Jane Austen is well worth rereading. P G Wodehouse isn't - anything > >that Wodehouse could do, Terry Pratchett can do better. Terry > >Pratchett is a lot better educated than Wodehouse was, and it shows. > > >> I'm now reading Enigma, the Turing biography. It's amazing the ideas > >> that they had about computers in about 1950. > > >Read old copies of Astounding Science Fiction - around 1950 - for > >really bizarre ideas about computers. > > I have "IBM's Early Computers" and some stuff like that. The current > concept of a base-2 synchronous-state-machine Von Neumann architecture > seems so obvious now, but it sure wasn't in the early days. At least > Turing appreciated that binary-decimal conversion could be done in > software. > > Maybe we should have stuck with the Harvard architecture.
Most signal-processing chips seem to use it
> Microsoft > has never learned the difference between code and data.
Turing pointed out that there's no fundamental difference. I quite liked self-modifying code, and used it in my 1968 PDP-8 program.
> It would be interesting to consider what sort of computer could be > built with early 1950s-sort of technology. Say, a few thousand dual > triodes and core memory.
Reliability would be an issue. Heated filaments don't last forever.Vacuum electronics can't hold a candle to solid-state devices when it comes to keeping on working. -- Bill Sloman, Nijmegen
John Larkin wrote:
> On Tue, 5 Jun 2012 07:48:12 -0700 (PDT), Bill Sloman > <bill.sloman@ieee.org> wrote: > >> On Jun 5, 4:16 pm, John Larkin >> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >>> On Mon, 4 Jun 2012 23:09:42 -0700 (PDT),BillSloman >>> >>> <bill.slo...@ieee.org> wrote: >>>> On Jun 4, 6:31 pm, John Larkin >>>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >>>>> On Mon, 4 Jun 2012 08:51:29 -0700 (PDT),BillSloman >>> >>>>> <bill.slo...@ieee.org> wrote: >>>>>> On Jun 4, 4:09 pm, John Larkin >>>>>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >>>>>>> On Mon, 4 Jun 2012 00:34:20 -0700 (PDT),BillSloman >>> >>>>>>> <bill.slo...@ieee.org> wrote: >>>>>>>> On Jun 4, 6:00 am, John Larkin >>>>>>>> <jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >>>>>>>>> On Sun, 3 Jun 2012 17:58:36 -0700 (PDT),BillSloman >>> >>>>>>>>> <bill.slo...@ieee.org> wrote: >>>>>>>>>> On Jun 3, 10:09 pm, Phil Hobbs >>>>>>>>>> <pcdhSpamMeSensel...@electrooptical.net> wrote: >>>>>>>>>>> BillSlomanwrote: >>> >>>>>>>>>>>> On Jun 3, 9:02 pm, Fred Abse<excretatau...@invalid.invalid> wrote: >>>>>>>>>>>>> On Sun, 03 Jun 2012 05:11:52 -0700,BillSlomanwrote: >>>>>>>>>>>>>> We've just measured a coupling of 0.98 in a gapped RM14 core - EPCOS >>>>>>>>>>>>>> gapped it down from 6000uH/root turn for an ungapped pair to 630nH per >>>>>>>>>>>>>> root turn by grinding back the centre pillar by 0.4mm, >>> >>>>>>>>>>>>> I think that should be "per turn squared". >>> >>>>>>>>>>>> Wrong. Inductance is proportional to the square of the number of >>>>>>>>>>>> turns, as long as they are closely coupled. >>> >>>>>>>>>>>> http://en.wikipedia.org/wiki/Inductor >>> >>>>>>>>>>> If L = alpha * N**2, then alpha has units of henries per turn squared. >>>>>>>>>>> (Of course a turn isn't really a unit, just as a radian and a steradian >>>>>>>>>>> aren't, but it sure isn't per square root turn.) >>> >>>>>>>>>> Applying dimensional analysis to a manufacturer's design fudge factor >>>>>>>>>> is the sort of thing that physicists do. >>> >>>>>>>>> Engineers, too. My first engineering course at Tulane, first semister >>>>>>>>> freshman year, was an introduction to units and dimensional analysis. >>>>>>>>> It was taught by Dr Johnson, the Dean of the Engineering School, who >>>>>>>>> thought it was important. >>> >>>>>>>>> Random noise increases as the square root of bandwidth, so we specify >>>>>>>>> it as volts per root Hz. >>> >>>>>>>>> Inductance increases with turns squared, so we spec a core Al as >>>>>>>>> henries per turn squared. >>> >>>>>>>>> See the difference? >>> >>>>>>>> It's 9:30am and my brain is working again, so yes - I do. >>> >>>>>>> Did you PWBC, post without benefit of coffee? I'm doing that now, and >>>>>>> it's a great hazard. >>> >>>>>>>>>> It's not a particularly useful activity. Reminding junior engineers at >>>>>>>>>> every possible opportunity that inductance is proportional to the >>>>>>>>>> square of the number of turns in a winding is an extremely useful >>>>>>>>>> activity, and saves loads of time at design reviews. >>> >>>>>>>>> They were probably polite enough to laugh at you after you left the >>>>>>>>> room. >>> >>>>>>>> Perhaps. But they'd got the point - attention-getting devices don't >>>>>>>> have to be pedantically correct to work. Look at Howard Johnson on >>>>>>>> high speed signal propagation. >>> >>>>>>> He's as dangerous as Professor Moriarty. >>> >>>>>> I don't know about dangerous, but pedagogically horrible. If you >>>>>> compare the lucid exposition of practical physics you get in Ralph >>>>>> Morrison's "Grounding and Shielding Techniques in Instrumentation" >>> >>>>>> http://www.amazon.com/Grounding-Shielding-Techniques-Ralph-Morrison/d... >>> >>>>>> with the incoherent messes that Howard Johnson peddles,you go from the >>>>>> sublime to the despicable. >>> >>>>> Yup. It's painful to read, even in the parts where he's technically >>>>> correct. >>> >>>>>>> (Incidentally, the latest "Sherlock" was stunning.) >>> >>>>>> You mean the BBC televison series? We've been watching it here - we >>>>>> get BBC 1 and 2 on the local cable - and liked it a lot. >>> >>>>> There are two running here now. The "classic" with Jeremy Brett, >>>>> pretty good, and the modern-day one. It's the new one that I was >>>>> referring to. I read all the Sherlocks several times when I was a kid, >>>>> and revisit them now and then for a quick read. >>> >>>> That makes you a Holmesian, rather than a Sherlock fan. I've just re- >>>> read Julina Barnes' "Arthur and George" >>> >>>> http://www.guardian.co.uk/books/2005/jun/26/fiction.shopping >>> >>>> which is essentially a portrait of Arthur Conan Doyle - a second rate >>>> author, who didn't recognise Holmes as his greatest creation. >>> >>> He claimed to have written one story during a break in a cricket game, >>> and killed him off because he was bored with him. >>> >>>> David Lodge does the English author biography a whole lot better. >>>> "Author, Author" about Henry James, and "A Man of Parts" about >>>> H.G.Wells, are both substantially better, perhaps because the subjects >>>> had a bit more to offer. >>> >>> I can't read either of them, for some reason. HJ is especially boring >>> to me... >> >> I can't read his novels - nothing ever happens. He wrote a few science- >> fiction short stories in the sytle of H.G.Wells (who was a friend of >> his) which aren't too bad. >> >> H.G.Wells was also a second rate novelist. His science fiction is >> interesting - the ideas are sufficiently interesting to transcend his >> defects as a novelist - if somewhat half-baked. His ideas about the >> shape of things to come weren't all that accurate, but his expectation >> that technological innovation would change the way we live was useful. >> >>> I've never made it halfway through any of his books. But I >>> can, and do, reread the better Jane Austens and PG Wodehouses >>> regularly. >> >> Jane Austen is well worth rereading. P G Wodehouse isn't - anything >> that Wodehouse could do, Terry Pratchett can do better. Terry >> Pratchett is a lot better educated than Wodehouse was, and it shows. >> >>> I'm now reading Enigma, the Turing biography. It's amazing the ideas >>> that they had about computers in about 1950. >> >> Read old copies of Astounding Science Fiction - around 1950 - for >> really bizarre ideas about computers. > > > I have "IBM's Early Computers" and some stuff like that. The current > concept of a base-2 synchronous-state-machine Von Neumann architecture > seems so obvious now, but it sure wasn't in the early days. At least > Turing appreciated that binary-decimal conversion could be done in > software. >
On a related note, Von Neumann berated his grad students for writing an assembler. Machine time was deemed too valuable for that purpose.
> Maybe we should have stuck with the Harvard architecture. Microsoft > has never learned the difference between code and data. >
Dunno how you have a program loader for Harvard - all the Harvard machines I've seen just pointed at zero ( whatever that meant ) and ran.
> It would be interesting to consider what sort of computer could be > built with early 1950s-sort of technology. Say, a few thousand dual > triodes and core memory. > >
Let's don't. Although the tiny JAN tubes might make that more fun. -- Les Cargill
On Tue, 5 Jun 2012 10:13:08 -0700 (PDT), Bill Sloman
<bill.sloman@ieee.org> wrote:

>On Jun 5, 5:55&#2013266080;pm, John Larkin ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> On Tue, 5 Jun 2012 07:48:12 -0700 (PDT),BillSloman >> >> >> >> >> >> >> >> >> >> <bill.slo...@ieee.org> wrote: >> >On Jun 5, 4:16 pm, John Larkin >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> On Mon, 4 Jun 2012 23:09:42 -0700 (PDT),BillSloman >> >> >> <bill.slo...@ieee.org> wrote: >> >> >On Jun 4, 6:31 pm, John Larkin >> >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> >> On Mon, 4 Jun 2012 08:51:29 -0700 (PDT),BillSloman >> >> >> >> <bill.slo...@ieee.org> wrote: >> >> >> >On Jun 4, 4:09 pm, John Larkin >> >> >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> >> >> On Mon, 4 Jun 2012 00:34:20 -0700 (PDT),BillSloman >> >> >> >> >> <bill.slo...@ieee.org> wrote: >> >> >> >> >On Jun 4, 6:00 am, John Larkin >> >> >> >> ><jjlar...@highNOTlandTHIStechnologyPART.com> wrote: >> >> >> >> >> On Sun, 3 Jun 2012 17:58:36 -0700 (PDT),BillSloman >> >> >> >> >> >> <bill.slo...@ieee.org> wrote: >> >> >> >> >> >On Jun 3, 10:09 pm, Phil Hobbs >> >> >> >> >> ><pcdhSpamMeSensel...@electrooptical.net> wrote: >> >> >> >> >> >>BillSlomanwrote: >> >> >> >> >> >> >> > On Jun 3, 9:02 pm, Fred Abse <excretatau...@invalid.invalid> wrote: >> >> >> >> >> >> > > On Sun, 03 Jun 2012 05:11:52 -0700,BillSlomanwrote: >> >> >> >> >> >> > > > We've just measured a coupling of 0.98 in a gapped RM14 core - EPCOS >> >> >> >> >> >> > > > gapped it down from 6000uH/root turn for an ungapped pair to 630nH per >> >> >> >> >> >> > > > root turn by grinding back the centre pillar by 0.4mm, >> >> >> >> >> >> >> > > I think that should be "per turn squared". >> >> >> >> >> >> >> > Wrong. Inductance is proportional to the square of the number of >> >> >> >> >> >> > turns, as long as they are closely coupled. >> >> >> >> >> >> >> >http://en.wikipedia.org/wiki/Inductor >> >> >> >> >> >> >> If L = alpha * N**2, then alpha has units of henries per turn squared. >> >> >> >> >> >> (Of course a turn isn't really a unit, just as a radian and a steradian >> >> >> >> >> >> aren't, but it sure isn't per square root turn.) >> >> >> >> >> >> >Applying dimensional analysis to a manufacturer's design fudge factor >> >> >> >> >> >is the sort of thing that physicists do. >> >> >> >> >> >> Engineers, too. My first engineering course at Tulane, first semister >> >> >> >> >> freshman year, was an introduction to units and dimensional analysis. >> >> >> >> >> It was taught by Dr Johnson, the Dean of the Engineering School, who >> >> >> >> >> thought it was important. >> >> >> >> >> >> Random noise increases as the square root of bandwidth, so we specify >> >> >> >> >> it as volts per root Hz. >> >> >> >> >> >> Inductance increases with turns squared, so we spec a core Al as >> >> >> >> >> henries per turn squared. >> >> >> >> >> >> See the difference? >> >> >> >> >> >It's 9:30am and my brain is working again, so yes - I do. >> >> >> >> >> Did you PWBC, post without benefit of coffee? I'm doing that now, and >> >> >> >> it's a great hazard. >> >> >> >> >> >> >It's not a particularly useful activity. Reminding junior engineers at >> >> >> >> >> >every possible opportunity that inductance is proportional to the >> >> >> >> >> >square of the number of turns in a winding is an extremely useful >> >> >> >> >> >activity, and saves loads of time at design reviews. >> >> >> >> >> >> They were probably polite enough to laugh at you after you left the >> >> >> >> >> room. >> >> >> >> >> >Perhaps. But they'd got the point - attention-getting devices don't >> >> >> >> >have to be pedantically correct to work. Look at Howard Johnson on >> >> >> >> >high speed signal propagation. >> >> >> >> >> He's as dangerous as Professor Moriarty. >> >> >> >> >I don't know about dangerous, but pedagogically horrible. If you >> >> >> >compare the lucid exposition of practical physics you get in Ralph >> >> >> >Morrison's "Grounding and Shielding Techniques in Instrumentation" >> >> >> >> >http://www.amazon.com/Grounding-Shielding-Techniques-Ralph-Morrison/d... >> >> >> >> >with the incoherent messes that Howard Johnson peddles,you go from the >> >> >> >sublime to the despicable. >> >> >> >> Yup. It's painful to read, even in the parts where he's technically >> >> >> correct. >> >> >> >> >> (Incidentally, the latest "Sherlock" was stunning.) >> >> >> >> >You mean the BBC televison series? We've been watching it here - we >> >> >> >get BBC 1 and 2 on the local cable - and liked it a lot. >> >> >> >> There are two running here now. The "classic" with Jeremy Brett, >> >> >> pretty good, and the modern-day one. It's the new one that I was >> >> >> referring to. I read all the Sherlocks several times when I was a kid, >> >> >> and revisit them now and then for a quick read. >> >> >> >That makes you a Holmesian, rather than a Sherlock fan. I've just re- >> >> >read Julina Barnes' "Arthur and George" >> >> >> >http://www.guardian.co.uk/books/2005/jun/26/fiction.shopping >> >> >> >which is essentially a portrait of Arthur Conan Doyle - a second rate >> >> >author, who didn't recognise Holmes as his greatest creation. >> >> >> He claimed to have written one story during a break in a cricket game, >> >> and killed him off because he was bored with him. >> >> >> >David Lodge does the English author biography a whole lot better. >> >> >"Author, Author" about Henry James, and "A Man of Parts" about >> >> >H.G.Wells, are both substantially better, perhaps because the subjects >> >> >had a bit more to offer. >> >> >> I can't read either of them, for some reason. HJ is especially boring >> >> to me... >> >> >I can't read his novels - nothing ever happens. He wrote a few science- >> >fiction short stories in the sytle of H.G.Wells (who was a friend of >> >his) which aren't too bad. >> >> >H.G.Wells was also a second rate novelist. His science fiction is >> >interesting - the ideas are sufficiently interesting to transcend his >> >defects as a novelist - if somewhat half-baked. His ideas about the >> >shape of things to come weren't all that accurate, but his expectation >> >that technological innovation would change the way we live was useful. >> >> >> I've never made it halfway through any of his books. But I >> >> can, and do, reread the better Jane Austens and PG Wodehouses >> >> regularly. >> >> >Jane Austen is well worth rereading. P G Wodehouse isn't - anything >> >that Wodehouse could do, Terry Pratchett can do better. Terry >> >Pratchett is a lot better educated than Wodehouse was, and it shows. >> >> >> I'm now reading Enigma, the Turing biography. It's amazing the ideas >> >> that they had about computers in about 1950. >> >> >Read old copies of Astounding Science Fiction - around 1950 - for >> >really bizarre ideas about computers. >> >> I have "IBM's Early Computers" and some stuff like that. The current >> concept of a base-2 synchronous-state-machine Von Neumann architecture >> seems so obvious now, but it sure wasn't in the early days. At least >> Turing appreciated that binary-decimal conversion could be done in >> software. >> >> Maybe we should have stuck with the Harvard architecture. > >Most signal-processing chips seem to use it > >> Microsoft >> has never learned the difference between code and data. > >Turing pointed out that there's no fundamental difference. I quite >liked self-modifying code, and used it in my 1968 PDP-8 program. >
Modern CPUs with MMUs can separate executable code from stacks and data; modern C compilers and OSs just don't bother much to use the facilities. That's why we have so many stack and buffer overflow trojans. -- John Larkin Highland Technology, Inc jlarkin at highlandtechnology dot com http://www.highlandtechnology.com Precision electronic instrumentation Picosecond-resolution Digital Delay and Pulse generators Custom laser drivers and controllers Photonics and fiberoptic TTL data links VME thermocouple, LVDT, synchro acquisition and simulation