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28 Cards in this Set
- Front
- Back
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App Inventor Designer:
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The Designer is used to create the interface of your own apps, and put them together from the functional components of AI. Essentially, the Designer is implemented as a Web application whereby you select and place objects on the "Screen" object, where each object has properties associated with it.
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App Inventor Blocks Editor:
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The Blocks Editor is where you bring the individual components of your app to life and assign them specific tasks, which collectively forms the functionality of your apps. In essence, it is implemented as a Java Web Start application, and provides for the selection of "puzzle pieces," which are directly associated with the objects selected in the Designer.
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Label Components
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the main function of a label is to display text. In addition to displaying static text, the Label Component also allows for dynamic changing of the label text, depending upon some event that occurs.
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Button Component
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interactive element of the GUI and, therefore, has blocks for event handling.
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CheckBox Component
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y clicking on a check box, you can enable a setting with a green check mark; to disable it, you click on the check box again. In handling events, the event blocks of the check box are mostly identical to those of the button.
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Process
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the activity of executing a program under the control of the operating system.
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Ready
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a process is "ready" if it is in a state in which its progress can continue
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Waiting
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it is "waiting" if its progress is currently delayed until some external event occurs, such as the completion of a mass storage operation, the pressing of a key at the keyboard, or the arrival of a message from another process
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Virtual Memory
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memory space whose presence is merely simulated by swapping blocks of data back and forth between a disk
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Main Memory
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memory actually present in the machine
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Circuit Switching
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circuit switching involves the establishment of a dedicated channel, or circuit, between two communicating parties. This form of switching is used in the Public Switched Telephone Network (PSTN)
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Packet Switching
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a message is disassembled into smaller components, called packets, each of which is directed from sender to receiver by way of packet forwarding, by routers. This form of switching is used for Internet communication
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Application layer
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Consists of those software units such as clients and servers that use Internet communication to carry out their tasks. Such software units include Web browsers, file transfer (FTP), remote login, email clients and servers, etc.
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Transport layer
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Establishes an end-to-end, logical “pipe” between sender and receiver, through which messages travel. Also subdivides original message into smaller “segments, which are sent “down” to the network layer for inclusion within packets.
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Network layer:
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Makes routing decisions for individual packets. Specifically, the network layer maintains routers’ forwarding tables, information of which is used to decide on the “next hop,” or router, along the path toward receiver of a message.
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Data link layer
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Transmits “packets” (called “frames”) from host to host on a single network (i.e., LAN). Today’s LANs employ Ethernet, both wired (CSMA/CD) and wired (CSMA/CA).
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Physical layer
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Consists of cables, ports, plugs, adapters, connectors, etc. Basically, this involves the actual physical connectivity between host and network.
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CPU
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The CPU is made of circuitry, which are electronic components wired together to control the flow of electrical signals. It is responsible for fetching program instructions from memory and executing those instructions.
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Memory
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The memory is the part of the computer that stores programs and data. Memory is commonly divided into (1) main memory (i.e., RAM and cache), which is fast, volatile, and expensive; and (2) secondary memory (i.e., hard disk and CD-ROM), which is slow, but permanent and inexpensive.
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I/O Devices
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Input devices allow the computer to receive data and instructions from an external source (e.g., keyboards, touch screen, microphone, etc.), whereas output devices allow the computer to display, print, or broadcast its results.
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Binary Search
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log2 N
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TCP/IP:
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(Transmission Control Protocol) and it controls the method by which messages are broken down into packets and then reassembled when they reach their final destination. (Internet Protocol) and it is concerned with labeling the packets for delivery and controlling the packets’ path from sender to receiver.
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HTTP
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(HyperText Transfer Protocol) and it determines how messages exchanged between browsers and Web servers are formatted
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Caching:
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a technique used by most browsers to avoid redundant and excessive downloading. When a page or image is first downloaded, it is stored in a temporary directory on the user’s computer. The next time the page or image is requested, the browser first checks to see if it has a copy stored locally in the cache, and, if so, whether the copy is up to date (accomplished by contacting the server and asking how recently the page was changed. If an up-to-date copy is stored locally, then the browser can display this copy, instead of downloading the original. . Caching does not reduce the number of interactions that take place between the browser and the Web server, since it is still necessary for the browser to contact the Web server, as the document on the server might have been modified since it was last cached; however, caching can still save time, because the browser avoids downloading redundant copies
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Transistor
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a piece of silicon whose conductivity can be turned on and off using an electric current. Since transistors were smaller, cheaper, more reliable, and more energy-efficient than vacuum tubes, they allowed for the production of more powerful yet inexpensive computers
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VLSI:
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(very large scale integration) Beginning in the late 1970s, VLSI offered the ability to manufacture hundreds of thousands or even millions of transistors on an IC (integrated circuit) chip.
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Embedded processors
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computer chips built into appliances and machinery to control their workings, and account for more than 90% of all computer processors. Modern houses contain hundreds of embedded processors, concealed in devices such as microwave ovens, television remote controls, cordless phones, and automatic thermostats. They also are used in automobiles (e.g., fuel injectors, anti-lock brakes, etc.)
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Digital Divide
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the fact that the benefits associated with computers are not shared equally by all. Americans with minority ancestry, lower incomes, and less education are less likely to be online than are other Americans. On a global scale, America, western Europe and certain Asian countries have much greater Internet connectivity than other parts of the world
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