This report documents and presents a top-level design and implementation plan for geographic information systems (GISs) for transportation. The basis for the design and implementation plan has been first an assessment of the current state of the art of GIS for transportation (GIS-T) through interviews with DOTs and MPOs and through a survey of GIS vendors, and second a projection of technological developments through the next five to ten years. A GIS-T may be thought of as a union of a GIS and a transportation information system, with enhancements to the GIS software and to the transportation data. A central significance of GIS-T technology is in its potential to serve as the long-sought data and systems integrator for transportation agencies. Given that so many transportation data are or can be geographically referenced, the GIS-T enabled and managed concept of location provides a basis for integrating databases and information systems across almost all transportation agency applications. In order to realize the greatest benefits of GIS-T, DOTs should develop agency-wide strategic plans that comprehend not only GIS technology adoption and application, but also concurrent adoption and application of open-systems standards and of a wide range of imminent complementary technologies, from computer networking and distributed computing, through new data storage media and database architectures, through computer-aided software engineering, to computer-based graphics and computer-aided design. The plans should address a full range of application scales, because GIS has the potential to become ubiquitous throughout all functional areas of transportation agencies. The recommended approach is top down for system design, then bottom up for application development. A GIS-T server-net architecture with computational and data management labor divided among different kinds of servers is recommended. (Fifteen kinds are suggested as a plausible first iteration for the required design.) Implementation of the server net can be incremental with a conceptual architecture in place as an organizing principle before complete physical realization is feasible, just as the concept of location can serve as a conceptual integrator for data schemas before the GIS enabled and managed spatial databases required for actual integration are fully available and as they are being incrementally constructed.

Adaptation of geographic information systems for transportation

A path is formed between a host computer and storage apparatuses without depending on the configuration of the host computer and a network and a plurality of volumes having a copy function are migrated between storage apparatuses while keeping the latest data. A computer system includes a host computer and first and second storage apparatuses, wherein the second storage apparatus virtualizes a plurality of migration source volumes as a plurality of migration destination volumes and provides them to the host computer; and if the second storage apparatus receives an input/output request for each migration destination volume, it reflects data in each migration source volume via each migration destination volume and the host computer cancels a path to each migration source volume and registers a path to each migration destination volume; and if the second storage apparatus receives a write request, it writes write data to each migration destination volume and each migration source volume and migrates copy processing control information and data until the termination of migration processing.

Computer system and data migration method

ion (an API) is important because it enables further extension of the system; it is a clean base upon which to build. The newline as newlineplus-carriage-return is an example of how to prevent logical extension of the system. For example, those in the Unix community most afflicted with microcephaly are enamored with the hack of generating files containing escape sequences that, when piped to the terminal cause some form of animation to appear. They gleefully mail these off to their friends instead of doing their homework. It’s a cute hack, but these files work only on one kind of terminal. Now imagine a world with an API for directing the terminal and the ability to embed these commands in files. Now those files can be used on any terminal. More importantly, this API forms a basis for expansion, for portable files, for a cottage industry. For example, add sound to the API, and the system can now boast being “multi-media.” Fundamentally, not only is an API needed, but it must either be in the kernel or be a standard dynamically linked library. Some part of the OS should track the terminal type and provide the necessary abstraction barrier. Some Unix zealots refuse to believe or understand this. They think that each program should send its own escape sequences to the terminal without requiring the overhead of an API. We have a proposal for these people. Let’s give them a system in which the disk is treated the same way the terminal is: without an API. Application programs get to send raw control commands to the disk. This way, when a program screws up, instead of the screen containing gibberish, the disks will contain gibberish. Also, programs will be dependent on the particular disks installed on the system, working with some but not with others. Of course, such a proposal for controlling a hard disk is insanity. Every disk drive has its own characteristics: these differences are best handled in 116 Terminal Insanity one place, by a device driver. Not every program or programmer is letterperfect: operations like reading or writing to the disk should be done only in one place within the operating system, where they can be written once, debugged, and left alone. Why should terminals be treated any differently? Forcing programmers to be aware of how their programs talk to terminals is medieval, to say the least. Johnny Zweig put it rather bluntly: Date: 2 May 90 17:23:34 GMT From: zweig@casca.cs.uiuc.edu (Johnny Zweig) Subject: /etc/termcap Newsgroups: alt.peeves2 In my opinion as a scientist as well as a software engineer, there is no reason in the world anyone should have to know /etc/termcap even EXISTS, let alone have to muck around with setting the right environment variables so that it is possible to vi a file. Some airhead has further messed up my life by seeing to it that most termcaps have the idea that “xterm” is an 80x65 line display. For those of us who use the X WINDOWS system to display WINDOWS on our workstations, 80x65 makes as much sense as reclining bucket seats on a bicycle—they are too goddamn big to fit enough of them on the screen. This idiot should be killed twice. It seems like figuring out what the hell kind of terminal I am using is not as hard as, say, launching nuclear missiles to within 10 yards of their targets, landing men on the moon or, say, Tetris. Why the hell hasn’t this bull been straightened out after 30 goddamn years of sweat, blood, and tears on the part of people trying to write software that doesn’t give its users the heebie-jeebies? And the first person who says “all you have to do is type ‘eval resize’ ” gets a big sock in the nose for being a clueless geek who missed the point. This stuff ought to be handled 11 levels of software below the level at which a user types a command—the goddamned HARDWARE ought to be able to figure out what kind of terminal it is, and if it can’t it should put a message on my console saying, “You are using piss-poor hardware and are a loser; give up and get a real job.”

The Unix-Haters Handbook

WFS is a shared file server available to a large network community. WFS responds to a carefully limited repertoire of commands that client programs transmit over the network. The system does not utilize connections, but instead behaves like a remote disk and reacts to page-level requests. The design emphasizes reliance upon client programs to implement the traditional facilities (stream IO, a directory system, etc.) of a file system. The use of atomic commands and connectionless protocols nearly eliminates the need for WFS to maintain transitory state information from request to request. Various uses of the system are discussed and extensions are proposed to provide security and protection without violating the design principles.

WFS: a simple shared file system for a distributed environment

Method to flexibly expand a storage array so that the I/O load is uniformly distributed among the new physical storage devices and the amount of copying resulting form the reorganization is minimized. The storage of the array is organized into reliability groups. The data of a reliability group is encoded and stored in blocks distributed among k physical storage devices. The invention supports any type of encoding; including those used by existing RAID levels. The storage array can be expanded by adding one or more physical storage devices. The mapping of reliability groups to physical storage devices is modified to take into account the new physical storage devices using a pseudo random replacement algorithm. The new mapping uniformly distributes the existing storage among the expanded array, yet minimizes the amount of data that must be reorganized.

Efficient expansion of highly reliable storage arrays and clusters

This chapter discusses file servers that are accessible via some form of local network or internetwork. It characterizes file services from the client point of view along a number of dimensions; distributivity of the service itself, the network environment of the service, the file model supported by the service, the kind(s) of atomic update provided by the service, the techniques used for controlling the allocation of files. It then describes the client interfaces to three existing file services. Finally, the impact of these features on design and implementation is discussed. An appendix contains characterizations of a variety of existing network-based file services using the criteria developed in the chapter.

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