Basic Definitions

Constructivism

Constructivism is a theory of learning based on the idea that knowledge is constructed by the knower based on mental activity. Learners are considered to be active organisms seeking meaning. Constructions of meaning may initially bear little relationship to reality (as in the naive theories of children), but will become increasing more complex, differentiated and realistic as time goes on.

Instructional Technology

once called Educational Technology, is a multidisciplinary field that applies theories of instruction, learning, behavioral and cognitive psychology, to the assessment, design, implementation, and evaluation of instructional materials, processes, and curricula.

Electronic Portfolio

A portfolio is a purposeful, meaningful collection of student work. This collection tells a story about the student's developmental growth achievements and progress over time.
All portfolios, regardless of type and purpose, are based upon the principles of students' collecting, selecting, and reflecting upon their work. All portfolios serve as windows on learning, enabling an audience to see a rich and complex view of student accomplishment, supported by authentic samples of student work. They are effective devices for communicating student achievement to parents, to teachers, and even to external reviewers such as employers and colleges. If portfolios become nothing more than storage containers for student work, their full potential is not realized. An electronic portfolio is the storage of this student information in a digital format.

Technology Definitions

The following definitions were retrieved from From "The Free On-line Dictionary of Computing, http://www.foldoc.org/, Editor Denis Howe"

Random-Access Memory

A data storage device for which the order of access to different locations does not affect the speed of access. This is in contrast to, say, a  magnetic disk, magnetic tape or a mercury delay line where it is very much quicker to access data sequentially because accessing a non-sequential location requires physical movement of the storage medium rather than just electronic switching.

The most common form of RAM in use today is built from semiconductor integrated circuits, which can be either static (SRAM) or dynamic (DRAM). In the 1970s magnetic core memory was used. RAM is still referred to as core by some old-timers.

The term "RAM" has gained the additional meaning of read-write. Most kinds of semiconductor read-only memory (ROM) are actually "random access" in the above sense but are never referred to as RAM. Furthermore, memory referred to as RAM can usually be read and written equally quickly (approximately), in contrast to the various kinds of programmable read-only memory. Finally, RAM is usually volatile though non-volatile random-access memory is also used.

Interestingly, some DRAM devices are not truly random access because various kinds of "page mode" or "column mode" mean that sequential access is faster than random access.

Read-Only Memory (ROM)

A type of data storage device which is manufactured with fixed contents. In its most general sense, the term might be used for any storage system whose contents cannot be altered, such as a gramophone record or a printed book; however, the term is most often applied to semiconductor integrated circuit memories, of which there are several types, and CD-ROM.

ROM is inherently non-volatile storage - it retains its contents even when the power is switched off, in contrast to RAM.

ROM is often used to hold programs for embedded systems since these usually have a fixed purpose. ROM is also used for storage of the lowest level bootstrap software (firmware) in a computer.

Floppy Disk

(Or "floppy", "diskette") A small, portable plastic disk coated in a magnetisable substance used for storing computer data, readable by a computer with a floppy disk drive. The physical size of disks has shrunk from the early 8 inch, to 5 1/4 inch ("minifloppy") to 3 1/2 inch ("microfloppy") while the data capacity has risen.

These disks are known as "floppy" disks (or diskettes) because the disk is flexible and the read/write head is in physical contact with the surface of the disk in contrast to "hard disks" (or winchesters) which are rigid and rely on a small fixed gap between the disk surface and the heads. Floppies may be either single-sided or double-sided.

3.5 inch floppies are less floppy than the larger disks because they come in a stiff plastic "envelope" or case, hence the alternative names "stiffy" or "crunchy" sometimes used to distinguish them from the floppier kind.

The following formats are used on IBM PCs and elsewhere:

Double denisty and high density are usually abbreviated DD and HD. HD 3.5 inch disks have a second hole in the envelope and an overlapping "HD" logo.

Hard Disk

In contrast to floppy disk). One or more rigid magnetic disks rotating about a central axle with associated read/write heads and electronics, used to store data. Most hard disks are permanently connected to the drive (fixed disks) though there are also removable disks.

High speed disks have an access time of 28 milliseconds or less, and low-speed disks run 65 milliseconds or more. The higher speed disks also transfer their data faster than the slower speed units.

Each surface of each disk is divided into a number of evenly spaced concentric circular tracks. The set of all tracks at a given radius on all surfaces (the tracks which can be accessed without moving the heads) are known as a cylinder. Each track is divided into sectors.

Disk drives are commonly characterised by the kind of interface used to connect to the computer, e.g. ATA, IDE, SCSI.

Central Processing Unit (CPU)

(CPU, processor) The part of a computer which controls all the other parts. Designs vary widely but, in general, the CPU consists of the control unit, the arithmetic and logic unit (ALU) and memory (registers, cache, RAM and ROM) as well as various temporary buffers and other logic.

The control unit fetches instructions from memory and decodes them to produce signals which control the other part of the computer. This may cause it to transfer data between memory and ALU or to activate peripherals to perform input or output.

A parallel computer has several CPUs which may share other resources such as memory and peripherals.

The term "processor" has to some extent replaced "CPU", though RAM and ROM are not normally considered as part of a processor. This is particularly true of common modern microprocessors though there have been microprocessors which include RAM and/or ROM on the same integrated circuit.

The CPU Info Center lists many kinds of CPU.