another bizarre architecture
in [Embedded]
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From: Didi on 8 Feb 2007 03:41 > These all derive from the functioning of the brain. It has been > experimentally determined that the human brain cannot accurately > keep track of more than roughly six or seven entities at once. > This is known as the 'rule of seven'. That's interesting to know, I had only a "feeling" based on my own experience. I (like most others, I suppose) have become used to writing just labels with some subroutines (functions, whatever) which return "to be written" error status so I can begin debugging as early as practical. I would say my limit is between 100 and 1000 lines at once (vpa or 68k or, well, 6800/09/11 assembly etc.) depending on how much of the effort is coding and how much algorithm development. The latter can actually make the 100 look unreachable sometimes. The piece of code I have been preparing in my head for weeks (without having the hardware to run it on, I had to decide whether to build the hardware based on that code feasibility and it was as marginal as it gets) was the real time loop of a TI DSP, I had to make sure things would work within 10 cycles.... they did. More basically, I would say if I don't have a binary to run after the first day of coding things don't look good :-). (I have not thrown away many days' typings because of that but not so few either). Dimiter ------------------------------------------------------ Dimiter Popoff Transgalactic Instruments http://www.tgi-sci.com ------------------------------------------------------ On Feb 8, 6:35 am, CBFalconer <cbfalco...(a)yahoo.com> wrote: > rickman wrote: > > CBFalconer <cbfalco...(a)yahoo.com> wrote: > >> Didi wrote: > > ... snip ... > > >>> The most critical rule I believe I have defined for myself is > >>> "never write at once more than you can hold in your head". > >>> After debugging a piece which is < your brain capacity, move > >>> on to the next piece :-). > > >> The corollary to that is "keep your functions short. One > >> screenful is usually enough"/ > > > Interesting. I was taught (back in the days of a CRT being a > > separate entity from the computer) the screenful rule of "thumb". > > But I have been working lately with Forth and am becomming a firm > > believer in the smaller the routine, the better. This certainly > > works in Forth and works well. > > These all derive from the functioning of the brain. It has been > experimentally determined that the human brain cannot accurately > keep track of more than roughly six or seven entities at once. > This is known as the 'rule of seven'. > > -- > <http://www.cs.auckland.ac.nz/~pgut001/pubs/vista_cost.txt> > <http://www.securityfocus.com/columnists/423> > > "A man who is right every time is not likely to do very much." > -- Francis Crick, co-discover of DNA > "There is nothing more amazing than stupidity in action." > -- Thomas Matthews
From: Andreas Kochenburger on 8 Feb 2007 05:06 "David Brown" <david(a)westcontrol.removethisbit.com> schrieb im Newsbeitrag news:45cae1cb$0$24618$8404b019(a)news.wineasy.se... > Connect the Lua interpreter to a serial port interface, and you've got an > extendible programmable command line interface into the heart of your > program. I've done this a couple of times - I should get in the habit of > doing it more. If you want to do it in Forth with a smaller footprint than Lua's, have a look at FICL. http://ficl.sourceforge.net/
From: rickman on 8 Feb 2007 08:15 On Feb 7, 11:35 pm, CBFalconer <cbfalco...(a)yahoo.com> wrote: > rickman wrote: > > CBFalconer <cbfalco...(a)yahoo.com> wrote: > >> Didi wrote: > > ... snip ... > > >>> The most critical rule I believe I have defined for myself is > >>> "never write at once more than you can hold in your head". > >>> After debugging a piece which is < your brain capacity, move > >>> on to the next piece :-). > > >> The corollary to that is "keep your functions short. One > >> screenful is usually enough"/ > > > Interesting. I was taught (back in the days of a CRT being a > > separate entity from the computer) the screenful rule of "thumb". > > But I have been working lately with Forth and am becomming a firm > > believer in the smaller the routine, the better. This certainly > > works in Forth and works well. > > These all derive from the functioning of the brain. It has been > experimentally determined that the human brain cannot accurately > keep track of more than roughly six or seven entities at once. > This is known as the 'rule of seven'. I recall a thread somewhere that discussed the origin of this "rule". That conversation traced it to a paper by one of the participants in the thread who said his original paper had to do with perception, not thinking. He claimed that the human senses could distinguish easily approximately seven levels of volume, tone, color and so on. That is not to say that we can only see seven colors, but if you were to attach them to objects or menus or similar, using much more than seven makes them hard to distinguish. I'm not disagreeing that seven is a good number for things you can hold in your head short term, I am saying that I have not seen a source for this claim. I'm pretty sure the magic number for me is a bit less, perhaps five. That may be why I have trouble with the stack when I program in Forth and have to make extensive use of stack notation.
From: rickman on 8 Feb 2007 08:22 On Feb 8, 5:06 am, "Andreas Kochenburger" <a...(a)nospam.org> wrote: > "David Brown" <d...(a)westcontrol.removethisbit.com> schrieb im Newsbeitragnews:45cae1cb$0$24618$8404b019(a)news.wineasy.se... > > > Connect the Lua interpreter to a serial port interface, and you've got an > > extendible programmable command line interface into the heart of your > > program. I've done this a couple of times - I should get in the habit of > > doing it more. > > If you want to do it in Forth with a smaller footprint than Lua's, have a > look at FICL.http://ficl.sourceforge.net/ I would love to use Forth, but right now there are no Forth vendors that support the ARM Cortex-M3 chips. I took a look at using FICL on an embedded target and it would take a fair amount of work to port it to such chips. Like most open source Forths, FICL is set up to run on a PC host. It has been a few years since I looked at FICL, so if I am mistaken, please let me know. But I don't think FICL is really intended for embedded use unless you are embedding a PC like device.
From: Vladimir Vassilevsky on 8 Feb 2007 10:53
CBFalconer wrote: > > These all derive from the functioning of the brain. It has been > experimentally determined that the human brain cannot accurately > keep track of more than roughly six or seven entities at once. > This is known as the 'rule of seven'. That is very optimistic. Most of people can't track even the single thing :) VLV |