Grid Definition and 222 Threads

GRiD Systems Corporation was founded in late 1979 by John Ellenby, who left his job at Xerox Parc and joined Glenn Edens, Dave Paulsen and Bill Moggridge to form one of Silicon Valley's first stealth companies. The company went public in March 1981. It was located at 47211 Lakeview Boulevard, Fremont, California, 94537.
The "GRiD" name with the unusual lowercase "i" in the middle was the result of discussion between John Ellenby, Glenn Edens and John Ellenby's wife, Gillian Ellenby, who pushed for the final choice. The lowercase "i" was a note of thanks to Intel for helping in the early daysGRiD developed and released several pioneering ideas:
First portable computer. Marketed almost exclusively to CEOs
The GRiD Compass 1100, the first clamshell laptop computer
Patented the "clamshell" laptop design
First portable to use non-volatile bubble-memory
GRiD-OS was a multi-tasking Text-based user interface or TUI and operating system
First use of electro-luminescent displays in a portable
First use of magnesium for the case
First use of the Intel 8086 and 8087 floating-point co-processor in a commercial product.
Pioneered the concept of a "bus" for connecting peripherals (using GPIB)
First computer that included a fully functional telephone and telephone handset
The first commercially available tablet-type portable computer was the GRiDPad, released in September 1989. Its operating system was based on MS-DOS.
A GRiD Compass 1101 was the first laptop in space. Required special modification to add a fan to pull air through the case. Subsequently a GRiD 1530 flew on STS-29 in March 1989.
OldComputers.net called the 1982 GRiD Compass 1101 the "grand-daddy of all present-day laptop computers". It had 256k RAM, an 8086, 320x240 screen, and 384k of internal 'bubble memory' that held data with power off.In 1988, Tandy Corporation purchased GRiD. AST Computer acquired the company, and was itself later acquired by Samsung.Edens co-founded Waveform Corp and in 2003 joined the board of F5 Networks Inc.John Ellenby went on to co-found the companies Agilis and Augmented Reality pioneer GeoVector.

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  1. DaveC426913

    Graphic: a global grid but not emanating from poles

    This is for a fictional project, but the tools I need will more likely be found here in Earth forum, I think. Move to fiction if necessary. I want to render a map of Earth with the "poles" of the grid in a different place. Say, the South "pole" of the grid is at Tierra del Fuego (ish) in S...
  2. R

    Calculating Voltage in a 6x6 Resistor Grid

    Homework Statement We have a resistor grid with 6x6 squres. ( figure below) If we know the voltage between ##O## and ##A##, what is the voltage between: ##a) O## and ##B## ##b) C## and ##D## ##c) E## and ##F## Every side has the same resistance. Attempt for solution: Because of the symmetry...
  3. E

    I Energy differences in different directions: the grid

    I heard a scientist propose a way to confirm (I feel that is a strong word) that there is a "grid" that subatomic particles and the smallest parts of the universe have to follow, instead of traveling freely. If energy moves sideways, it will lose energy more quickly for the same distance as...
  4. AsadQZR

    How does turning off a light bulb affect the entire electric grid?

    Hello Physics Forums, this is my first post! I wanted to know how the current electrical grid system works. I mean, not in terms of creation, transmission, and distribution, but rather, how you would draw it on a circuit diagram. I understand that an AC current is generated at the power factory...
  5. S

    Construction of a pentagon using only the grid system

    I have found a way to construct a pentagon using only the grid system. The internal angles are all within 99% accuracy and all the angles to the 3rd decimal add up exactly to 540 degrees. This is without the use of a compass and bearing in mind that the internal lines intersect at the ration of...
  6. sehrish shakir

    Pressure drop in rod bundles without spacer grid

    Hello! I am studying the mentioned topic I am confused in calculating the average value of friction factor in sub channels ... please help ?? thank you in advance
  7. kostoglotov

    Good beginner's resources for power factors and grids

    I am doing a BSEE and going power side. I am also applying for scholarships and bursaries, and would like to be able to talk specifically about power factors. More than this though, I want to understand it. Most of what I've found so far is very specialized and technical. What good resources...
  8. G

    How many ways can one reach point (a,b) starting from (0,0)?

    Homework Statement We fit the plane with a coordinate system, and we consider the set of points with coordinates in ##\mathbb{N}\times\mathbb{N} ##. To link two points in this coordinate system, we only allow unit displacements, and only increasing displacements. In how many ways can one...
  9. A

    Why Grid North doesn't agree with True North on maps

    when I look at large scale map such as USGS top maps, i noticed that maps' grid are not aligned with the map frame. looking at the declination diagram at the bottom of the map, there's a difference between true north and GN (Grid north) can someone explain to me why the map grid doesn't align...
  10. S

    Which Solar Setup is Best for a Zero-Feed Tariff Family Home?

    For an economical PV system, with zero-feed in tariff, for a family home, with no one at home during the day time, the best setup option would be: (some components might be in another) 1) PV, batteries, charge controller, inverter 2) PV, MPP tracker, batteries, charge controller, inverter 3)...
  11. ugenetic

    Power Grid, L goes up, why grid current goes up as well?

    I am on a perpetual quest to understand reactive power. one of the road blocks I encountered is this text: " if inductive load in the grid increases, voltages across loads will drop. In order to maintain power delivered, grid current has to increase" That statement is quite frustrating to...
  12. M

    I Possible webpage title: Can You Solve This Number Grid Puzzle?

    Greetings, Found this grid from Internet. There was no hint if this was a puzzle but I pretty much sure that it is. Has someone seen this kind of grid before? If so, how to solve this? The link to the grid is: https://www.geocaching.com/geocache/GC6FQYC_pvm-6-chimney
  13. Telemachus

    Numerov method on a exponential grid mesh

    Hi there. I was trying to implement Numerov method for solving second order differential equations (you can see some information of Numerov algorithm at here: https://en.wikipedia.org/wiki/Numerov%27s_method ). At the beginning I've used a uniform grid mesh, all points equally spaced. I'm...
  14. Telemachus

    Variable grid mesh in Numerov's method (Fortran)

    I was trying to implement a variable grid mesh in Numerov's method, while playing with fortran. Numerov method was working well with a standard discretization, but when I tried to implement this variable grid, things came to look as if the 'metric' of the function were depending on the...
  15. L

    Voltage and Frequency Regulation (Grid, synchronous generation)

    Hi I was wondering if someone could help me understand and explain to me how one can control the frequency of the grid from help of the active power (frequency -> power angle -> active power) and how reactive power can be used to control the voltage level. My thoughts: Voltage Control: I don't...
  16. cnh1995

    Synchronization of an alternator to the grid

    When an alternator is synchronized to the grid, its voltage and frequency are same as those of the grid. So, it shouldn't take any load at that instant. How is it brought into operation then? What is the procedure followed practically? My book says prime mover is given some extra energy so the...
  17. G

    I Drawing a Continuous Symmetrical Grid on a Sphere's surface

    The motivation for this thread comes from physics, but I'm posting it in the maths section as the question is more of a mathematical one and less concerned with the underlying physics. In cosmology, they often talk about closed universes with positive curvature, or non-Euclidean elliptic...
  18. EinsteinKreuz

    Creating a Grid w/Square Elements for a Cayley Table

    Is there a way to create a grid here on PF that has square elements? I ask because I'm yearning to make a post that will require a Cayley table.
  19. L

    Number of Paths from O(0,0) to A(7,8) - No (3,4)

    Homework Statement In a grid O(0,0) A(7,8) find the number of paths that 1. pass through (3,4) 2. don't pass through (3,4) 3. pass through M(2,3) AND N(4,6) 4. DON'T pass pass through M(2,3) and N(4,6) 5. pass through ONLY ONE of M(2,3) and N(4,6) 6. pass through AT LEAST ONE of M(2,3) and...
  20. W

    "Crow Flies Distance" On a Rectangular Grid -- Definition?

    Hi all, I am looking for a precise definition of " Crow Flies Distance" on a rectangular grid. I have not found a precise definition yet, but from what I have read, I think it would be the standard Euclidean distance ## d((x_1,y_1),(x_2,y_2)) = \sqrt {( (x_1-x_2)^2+(y_1-y_2)^2}) ## Is this...
  21. L

    Testing rear window defroster grid

    Hello, I would like to develop a testing method to detect window defroster grid failures. Rear windows has 12 heating wires painted to the glass and cca. 2% are faulty pieces. I tried to measure the resistance, current and voltage drop of good parts and compare results with those where was at...
  22. N

    Finite Difference Method for non-square grid

    Hi, I have written some codes for the finite difference solution of diffusion equation (\frac{\partial c}{\partial t}= D {\nabla^2 c}, where c is the species concentration and D is the diffusion coefficient) as follows: DO k= 1, tsteps+1 DO i = 2, zsteps DO j = 2, rsteps...
  23. M

    MHB 25 x 25 Grid, find how many shaded squares

    pls help with the formula on solving these the easy way. It took time for me to find the answer by drawing it literally. my answer is 334 squares.
  24. amtech

    What is Australian Grid Code for solar energy integration?

    Hi, I am working on Solar systems in Australia. I want to know the Australian standards for grid connected PV systems for voltage, power factor, reactive power etc.
  25. Sanchayan

    Can Kirchoff's Laws Be Applied to Solve Hexagonal Grid Resistance?

    https://brilliant.org/problems/hexagonal-grid/ I've been pondering on this but not being able to solve.I mean applying Kirchoff's law here is of no use. Any ideas?
  26. V

    Using fft on a partially staggered grid

    Hi, I was wondering if anyone could give me a hand. I am wondering if it possible to use standard spectral methods to compute the derivative of a function on a partially staggered grid. e.g. from 0 to pi I would perform the differentiation on the nodes j*(pi/N) j=1,2,3 ... N-1 and from 0...
  27. S

    How is the US power grid kept in phase?

    A quick calculation shows that across the continental United States, spanning about 3000 miles, there is a delay from east to west coast of about 1/60th of a second. 3000 miles divided by 186,000 miles per second. This is a full cycle phase variation cost to cost. Is there truly "The Power...
  28. P

    What does a leading/lagging angle mean on the grid?

    I ran across a project at the Univ. of Tennessee that has deployed a network of frequency meters around the power grid in the US. see http://fnetpublic.utk.edu/anglecontour.html I understand the frequency excursions may indicate unexpected events like generator trips or loss of load. What do...
  29. h6ss

    What Is the Probability of Seeing a Point on an Infinite Grid?

    Here is a difficult probability question I found interesting and thought I'd share: Suppose you are standing on an infinitely large square grid at the point (0,0), and suppose that you can see infinitely far but cannot see through grid points. Given a random grid point z = (x, y), where x and y...
  30. DivergentSpectrum

    Construct a regular grid in a rectangular box in 3 dimensional space

    Im trying to construct a regular grid in a rectangular box in 3 dimensional space heres what i have to work with: x has a range between xmin and xmax y has a range beween ymin and ymax z has a range between zmin and zmax the total number of points is limited to a specific number n i want the...
  31. O

    Grid tie inverter distorting waveform

    I've just wired in a 1kw grid tie inverter, feeding the power from solar panels into the mains grid, ( in Thailand , so no rules or regulations). There are some problems I've noticed. Toaster buzzes , but works. Induction cooker won't work, lights come on , fan works but no heat delivered, when...
  32. neeraj kaira

    Decelerating Electrons & Releasing Energy: Reflector Plate Grid Dynamics

    When the beam of electrons reflect back to the grid due to the repeller voltage in reflector plate ,how the grid decelerates the returning electrons ?? And how they release their energy to the grid ?
  33. Vigardo

    Boundary conditions for a grid tube under combined loading

    Dear experts, I´m trying to model in ANSYS Mechanical (v14.5) the linear buckling behavior of a cylinder made of BEAM4 elements under combined loading (axial compression and bending moment) applied at the ends. How should I set up the boundary conditions of a cylinder to keep rigid the ends...
  34. X

    Recalculation of center of mass on a grid

    Hi, I checked the forum rules and homework / coursework is not allowed so I am not sure if this is appropriate or not. Feel free to guide me through appropriate forum and/or lock this thread if such questions are not allowed. The question I have is mostly related with my research and since I am...
  35. K

    Mehrstellenverfahren for different grid spacing along the three space directions

    Hi everybody, I need to discretize a differential equation. The grid that I am considering has a different grid spacing along the three space directions. That is, hx different than hy and hz. For that purpose, I would like to discretize the differential equation through the Mehrstellenverfahren...
  36. S

    Calculating Strain Gauge Grid Line Output

    Hello, I would like to know, how to calculate the number of grid lines( or loops) in a strain gauge. I'm trying to calculate the output form the each grid lines. Thanks in advance
  37. BeautifulLight

    How is the grid biased on a triode vacuum tube amplifier?

    Here is my single triode vacuum tube amplifier circuit I understand there needs to be a bias on the grid otherwise the signal will be rectified -not amplified. Is biasing the grid as simple as running a resistor in-between the grid and the cathode on the power supply like this (in red)...
  38. O

    Solar - Grid Tie - Energy meter increases?

    Hi, So I trialed a 400W grid tie inverter which I had laying about to experiment with lowering the amount of energy the house is drawing from the grid with a single 100W solar panel I have on the roof to charge some batteries. I have a "smart meter" which measures how much power the house is...
  39. P

    Problem: How can American 110V light bulbs be used on a 240V grid?

    Homework Statement In America power is supplied at 110 V. In Australia power is supplied at 240 V, however American lights are routinely used in Australia. a) How is this possible? b) Calculate the power that a pair of 1000 W 110 V light would dissipate when plugged into a 240 V system in...
  40. W

    Dimensional Consistency in Grid Defintions

    Hi everyone. I hope this is in the proper place - not sure where to put it. Anyway, I am working on an optimization problem in the research I am doing and my partner and I have found that in order to quickly converge on a solution using a specific PSO (the firefly algorithm - it's awesome, look...
  41. deep838

    Width of a wire grid polarizer

    Why is it that the width of a wire grid polarizer has to be less than the wavelength of the wave which I want to polarize? What would happen if the width was a little bit more?
  42. ugenetic

    AC generator on grid: Governor and Amp

    Hi Forum, once again I seek your help I have a very good understanding of rotating magnetic field due to stator, armature reaction, and the phasor diagram. from energy point of view it is very clear that if Gov increases, while output voltage remains locked by the gird, Amp will increase...
  43. seb7

    Is the speed of light truly constant in all directions?

    Something that's been bugging me, but unable to find an answer for.. The speed of light (in a vacuum) is absolute, well not really, its relative to the space/time its in. ie. The distant galaxies are moving away from us, but their local light speed is relative to their space/time. So since...
  44. T

    How to Determine Intersection Points for SPH to Eulerian Grid Conversion?

    Hello! I'm currently working on an algorithm that converts SPH (smoothed particle hydrodynamics) data to an Eulerian grid. Basically, the problem is this: each sph particle has an associated smoothing length, which is effectively the radius of a sphere centered at the sph particle's position...
  45. A

    Conway's experiment: simultaneous grid change

    Hi, In Conway's experiment it is said that the changes in the grid happen simultaneously between each tick. How is it possible for the changes to happen simultaneously since all cells are dependent to one another ? Can anyone explain this and give an example ? Thank you in advance, Alex...
  46. M

    What is the grid of the universe and how does it explain the bending of space?

    Since everything in the universe can be calculated using 3D grid mathematics, it seems logical that universe would be ON a grid of some sort. So then what would the grid be, exactly? After dwelling on this idea for a while, I came to the conclusion that it would have to be space itself...
  47. J

    Software capable of modeling ground grid performance during faults cau

    For a University project I need to somehow model the effective performance of a ground grid in the event of a fault caused by a lightning strike. We would need to prepare different test cases for different sizes and grid configurations in order to carry out different analysis and find the...
  48. M

    How to Connect a PV Module with the Grid?

    I am working on a project. I have completed designing PV module in simulink. I have also added MPPT algorithm and Boost Converter. Now I want to connect it with a grid. Can anybody tell me the circuit diagram?
  49. C

    What are the possible routes from A to D in a 2D grid?

    Hi all. I have a grid with 4 points, A, B, C, and D. Each valid move is either going to the right for one block or going down for 1 block. Here is the grid. I need to calculate the following: a) How many different valid routes from A to D? b) How many valid routes from A to D that must avoid...
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