SUMMARY / RELATED TOPICS

Gary Kildall

Gary Arlen Kildall was an American computer scientist and microcomputer entrepreneur who created the CP/M operating system and founded Digital Research, Inc.. Kildall was one of the first people to see microprocessors as capable computers, rather than equipment controllers, to organize a company around this concept, he co-hosted the PBS TV show The Computer Chronicles. Although his career in computing spanned more than two decades, he is remembered in connection with IBM's unsuccessful attempt in 1980 to license CP/M for the IBM Personal Computer. Gary Kildall was born and grew up in Seattle, where his family operated a seamanship school, his father, Joseph Kildall, was a captain of Norwegian heritage. His mother Emma was of half Swedish descent, as Gary's grandmother was born in Långbäck, Sweden, in Skellefteå Municipality, but emigrated to Canada at 23 years of age. Gary attended the University of Washington hoping to become a mathematics teacher, but became interested in computer technology.

After receiving his degree, he fulfilled a draft obligation to the United States Navy by teaching at the Naval Postgraduate School in Monterey, California. Being within an hour's drive of Silicon Valley, Kildall heard about the first commercially available microprocessor, the Intel 4004, he began writing experimental programs for it. To learn more about the processors, he worked at Intel as a consultant on his days off. Kildall returned to UW and finished his doctorate in computer science in 1972 resumed teaching at NPS, he published a paper that introduced the theory of data-flow analysis used today in optimizing compilers, he continued to experiment with microcomputers and the emerging technology of floppy disks. Intel lent him systems using the 8008 and 8080 processors, in 1973, he developed the first high-level programming language for microprocessors, called PL/M. For Intel he wrote an 8080 instruction set simulator named INTERP/80, he created CP/M the same year to enable the 8080 to control a floppy drive, combining for the first time all the essential components of a computer at the microcomputer scale.

He demonstrated CP/M to Intel. Kildall and his wife Dorothy established a company called "Intergalactic Digital Research", to market CP/M through advertisements in hobbyist magazines. Digital Research licensed CP/M for the IMSAI 8080, a popular clone of the Altair 8800; as more manufacturers licensed CP/M, it became a de facto standard and had to support an increasing number of hardware variations. In response, Kildall pioneered the concept of a BIOS, a set of simple programs stored in the computer hardware that enabled CP/M to run on different systems without modification. CP/M's quick success took Kildall by surprise, he was slow to update it for high density floppy disks and hard disk drives. After hardware manufacturers talked about creating a rival operating system, Kildall started a rush project to develop CP/M 2. By 1981, at the peak of its popularity, CP/M ran on 3000 different computer models and DRI had US$5.4 million in yearly revenues. IBM, presided by John R. Opel, approached Digital Research in 1980, at Bill Gates' suggestion, to negotiate the purchase of a forthcoming version of CP/M called CP/M-86 for the IBM PC.

Gary had left negotiations to his wife, Dorothy, as he did, while he and colleague and developer of MP/M operating system Tom Rolander used Gary's private airplane to deliver software to manufacturer Bill Godbout. Before the IBM representatives would explain the purpose of their visit, they insisted that Dorothy sign a non-disclosure agreement. On the advice of DRI attorney Gerry Davis, Dorothy refused to sign the agreement without Gary's approval. Gary returned in the afternoon and tried to move the discussion with IBM forward, but accounts disagree on whether he signed the non-disclosure agreement, as well as if he met with the IBM representatives. Various reasons have been given for the two companies failing to reach an agreement. DRI, which had only a few products, might have been unwilling to sell its main product to IBM for a one-time payment rather than its usual royalty-based plan. Dorothy might have believed that the company could not deliver CP/M-86 on IBM's proposed schedule, as the company was busy developing an implementation of the PL/I programming language for Data General.

Possible, the IBM representatives might have been annoyed that DRI had spent hours on what they considered a routine formality. According to Kildall, the IBM representatives took the same flight to Florida that night that he and Dorothy took for their vacation, they negotiated further on the flight, reaching a handshake agreement. IBM lead negotiator Jack Sams insisted that he never met Gary, one IBM colleague has confirmed that Sams said so at the time, he accepted that someone else in his group might have been on the same flight, but noted that he flew back to Seattle to talk with Microsoft again. Sams related the story to Gates, who had agreed to provide a BASIC interpreter and several other programs for the PC. Gates' impression of the story was that Gary capriciously "went flying", as he would tell reporters. Sams left Gates with the task of finding a usable operating system, a few weeks he proposed using the operating system 86-DOS—an independently developed operating system that implemented Kildall's CP/M API—from Seattle Computer Products.

Paul Allen negotiated a licensing deal with SCP. Allen had 86-DOS adapted for IBM's hardware, IBM shipped it as IBM PC DOS. Kildall obtained a copy of PC

Channelling (physics)

Channelling is the process that constrains the path of a charged particle in a crystalline solid. Many physical phenomena can occur when a charged particle is incident upon a solid target, e.g. elastic scattering, inelastic energy-loss processes, secondary-electron emission, electromagnetic radiation, nuclear reactions, etc. All of these processes have cross sections which depend on the impact parameters involved in collisions with individual target atoms; when the target material is homogeneous and isotropic, the impact-parameter distribution is independent of the orientation of the momentum of the particle and interaction processes are orientation-independent. When the target material is monocrystalline, the yields of physical processes are strongly dependent on the orientation of the momentum of the particle relative to the crystalline axes or planes. Or in other words, the stopping power of the particle is much lower in certain directions than others; this effect is called the "channelling" effect.

It is related to other orientation-dependent effects, such as particle diffraction. These relationships will be discussed in detail later; the channelling effect was first discovered in binary collision approximation computer simulations in 1963 to explain exponential tails in experimentally observed ion range distributions that did not conform to standard theories of ion penetration. The simulated prediction was confirmed experimentally the following year by measurements of ion penetration depths in single-crystalline tungsten. From a simple, classical standpoint, one may qualitatively understand the channelling effect as follows: If the direction of a charged particle incident upon the surface of a monocrystal lies close to a major crystal direction, the particle with high probability will only do small-angle scattering as it passes through the several layers of atoms in the crystal and hence remain in the same crystal'channel'. If it is not in a major crystal direction or plane, it is much more to undergo large-angle scattering and hence its final mean penetration depth is to be shorter.

If the direction of the particle's momentum is close to the crystalline plane, but it is not close to major crystalline axes, this phenomenon is called "planar channelling". Channelling leads to deeper penetration of the ions in the material, an effect, observed experimentally and in computer simulations, see Figures 3-5. Negatively charged particles like antiprotons and electrons are attracted towards the positively charged nuclei of the plane, after passing the center of the plane, they will be attracted again, so negatively charged particles tend to follow the direction of one crystalline plane; because the crystalline plane has a high density of atomic electrons and nuclei, the channeled particles suffer a high angle Rutherford scattering or energy-losses in collision with electrons and leave the channel. This is called the "dechannelling" process. Positively charged particles like protons and positrons are instead repelled from the nuclei of the plane, after entering the space between two neighboring planes, they will be repelled from the second plane.

So positively charged particles tend to follow the direction between two neighboring crystalline planes, but at the largest possible distance from each of them. Therefore, the positively charged particles have a smaller probability of interacting with the nuclei and electrons of the planes and travel longer distances; the same phenomena occur when the direction of momentum of the charged particles lies close to a major crystalline, high-symmetry axis. This phenomenon is called "axial channelling". At low energies the channelling effects in crystals are not present because small-angle scattering at low energies requires large impact parameters, which become bigger than interplanar distances; the particle's diffraction is dominating here. At high energies the quantum effects and diffraction are less effective and the channelling effect is present. There are several interesting applications of the channelling effects. Channelling effects can be used as tools to investigate the properties of the crystal lattice and of its perturbations in the bulk region, not accessible to X-rays.

The channeling method may be utilized to detect the geometrical location of interstitials. This is an important variation of the Rutherford backscattering ion beam analysis technique called Rutherford backscattering/channeling. At higher energies, the applications include the channelling radiation for enhanced production of high energy gamma rays, the use of bent crystals for extraction of particles from the halo of the circulating beam in a particle accelerator. J. W. Mayer and E. Rimini, Ion Beam Handbook for Material Analysis, Academic Press, New York L. C. Feldman, J. W. Mayer and S. T. Picraux, Material Analysis by Ion Channelling, Academic Press, New York R. Hovden, H. L. Xin, D. A. Muller, Phys. Rev. B 86, 195415 arXiv:1212.1154 G. R. Anstis, D. Q. Cai, D. J. H. Cockayne, Ultramicroscopy 94, 309. D. Van Dyck and J. H. Chen, Solid State Communications 109, 501. S. Hillyard and J. Silcox, Ultramicroscopy 58, 6. S. J. Pennycook and D. E. Jesson, Physical Review Letters 64, 938. M. V. Berry and Ozoriode.

Am, Journal of Physics a-Mathematical and General 6, 1451. M. V. Berry, Journal of Physics Part C Solid State Physics 4, 697. A. Howie, Philosophical Magazine 14, 223. P. B. Hirsch, A. Howie, R. B. Nicholson, D. W. Pashley, M. Whelan, Electron microscopy of thin crystals. J. U. Andersen, Notes on Channeling, http://phys.au.dk/en/publications/lecture-notes/ (2

Sugao Station

Sugao Station is a railway station in Bungo-Ono City, Ōita Prefecture, Japan. It is on the Hōhi Main Line; the station is served by the Hōhi Main Line and is located 117.3 km from the starting point of the line at Kumamoto. The station consists of two side platforms serving two tracks with a siding; the station building is a modern wooden structure, unstaffed and serves only as a waiting room with an automatic ticket vending machine. A ramp leads up to the station building from the forecourt but access to the opposite platform is by means of a footbridge. Japanese Government Railways had opened the Inukai Light Rail Line from Ōita to Nakahanda on 1 April 1914; the track was extended westwards in phases, with Miemachi opening as the new western terminus on 27 March 1921. On the same day, Sugao was opened as an intermediate station on the new track. By 1928, the track been extended further west and had linked up with the Miyagi Line reaching eastwards from Kumamoto. On 2 December 1928, the entire track from Kumamoto through Sugao to Ōita was designated as the Hōhi Main Line.

With the privatization of Japanese National Railways, the successor of JGR, on 1 April 1987, the station came under the control of JR Kyushu. In September 2017, Typhoon Talim damaged the Hōhi Main Line at several locations. Services between Aso and Nakahanda, including Sugao, were replaced by bus services. Normal rail services between Aso and Ōita were restored by 2 October 2017. In fiscal 2015, there were a total of 69,416 boarding passengers, giving a daily average of 190 passengers. List of railway stations in Japan Sugao