Information Technology: Computer Systems, Hardware, Software, Storage, and Data Processing

Comprehensive vocabulary flashcards covering computer hardware, storage devices, input/output peripherals, computer classifications, data verification/validation, software categories, mainframes, and Excel analysis tools.

Primary Storage

Also called main memory or immediate access storage, it is volatile memory made up of RAM and ROM chips that directly holds programs and data currently in use by the computer.

RAM (Random Access Memory)

A volatile primary storage chip whose contents can be read, written to, and accessed directly; all data stored in RAM is lost when the computer loses power.

ROM (Read Only Memory)

A non-volatile primary storage chip whose contents are hardwired and can only be read; it holds the address of start-up or boot-up programs and retains data when power is turned off.

PROM (Programmable Read Only Memory)

A type of ROM chip that can be written to exactly once using a special machine, after which it permanently behaves as standard read-only memory.

EPROM (Erasable Programmable Read Only Memory)

A type of ROM chip that can be erased and rewritten using ultraviolet light; it does not last as long as PROM due to repeated erasing and must be protected from sunlight.

EEPROM (Electrically Erasable Programmable Read Only Memory)

A specialized ROM chip that can be erased completely using an electrical charge rather than ultraviolet light.

Secondary Storage

Also known as backing storage, auxiliary storage, or permanent storage; non-volatile storage that retains large volumes of data and programs permanently and is not directly accessed by the CPU.

Storage Device vs. Storage Media

A storage device contains its own internal circuitry to read or write data (e.g., hard disk drive, tape drive), whereas storage media lacks internal circuitry and requires a separate device to read or write data (e.g., floppy disk, CD).

Bit

Short for binary digit, it is the smallest unit of storage in a computer and can represent either a 0 or a 1.

Nibble

A storage unit consisting of a collection of four bits, or half of a byte.

Byte

A collection of 8 bits representing a single character, such as a letter, number, symbol, punctuation mark, or space.

Kilobyte (KB)

A storage measurement representing approximately $1000$ bytes, with an actual exact value of $2^{10} = 1024$ bytes.

Megabyte (MB)

A storage measurement representing approximately $1000\,\text{KB}$ (or $1\,000\,000$ bytes), with an actual exact value of $2^{20} = 1\,048\,576$ bytes.

Gigabyte (GB)

A storage measurement representing approximately $1000\,\text{MB}$ (or $1\,000\,000\,000$ bytes), with an actual exact value of $2^{30} = 1\,073\,741\,824$ bytes.

Terabyte (TB)

A storage measurement representing approximately $1000\,\text{GB}$ (or 1 trillion bytes), with an actual exact value of $2^{40} = 1\,099\,511\,627\,776$ bytes.

Hardcopy Output vs. Softcopy Output

Hardcopy output is permanent tangible output such as a printed document, whereas softcopy output is temporary visual or auditory output such as monitor displays or sound from speakers.

Dot Matrix Printer

An impact printer that uses pins in its print head to strike an inked ribbon against paper; it operates at around $50\,\text{cps}$, produces noisy and low-quality output, and is primarily used for bills and multi-part reports.

Daisy Wheel

A circular impact printing element with character-bearing spokes radiating from a central hub, struck by a hammer against an ink ribbon to produce characters on paper.

Laser Printer

A fast, high-quality non-impact page printer that utilizes a laser beam, special toner, and a photoconductive rotating drum to produce text and graphic prints.

Inkjet Printer

A non-impact printer that sprays tiny, electrically charged droplets of liquid ink onto paper; it prints between $1\text{ to }16$ pages per minute and is common in homes and small offices.

Graph Plotter

A specialized printer that draws continuous vector lines on paper using pens held in a mechanical arm to produce architectural blueprints, maps, graphs, and charts.

3D Printing

The additive manufacturing process of creating physical three-dimensional objects from a CAD digital model by depositing successive thin layers of material such as nylon, plastic, wood, resin, or metal.

LED Monitor

A flat-panel display using Light Emitting Diodes that replaced LCDs; it provides slim design, lower power consumption, true black image quality, flicker-free display, and zero motion delay.

Computer Output on Microfilm (COM)

An archival technique used by organizations like newspaper publishers that photographs and micro-sizes large volumes of documents onto rolls of microfilm or sheets of microfiche.

Virtual Keyboard

An input device that projects an optical pattern of keys with red laser light onto a flat surface and detects keystrokes via optical or infrared sensing.

MICR (Magnetic Ink Character Recognition)

A specialized scanning technology used in the banking sector to read account, branch, and check numbers printed with magnetic ink, remaining legible even if folded or soiled.

OMR (Optical Mark Recognition)

A scanning technology that detects pencil or dark shading marks on predefined paper locations, widely used for grading multiple-choice exams and survey questionnaires.

OCR (Optical Character Recognition)

A data capture technology that reads printed alphanumeric characters from physical documents such as airline tickets, postal mail codes, and utility bills.

Barcode Reader

An optical input device that reads vertical bars of varying widths and spacing to identify items, look up prices, and update inventory counts automatically in retail POS systems.

RFID (Radio Frequency Identification)

A wireless data collection technology that uses radio frequency signals to read data stored on an embedded chip tag without requiring direct line-of-sight.

Biometrics

Security and authentication input systems that identify individuals based on unique physiological traits, including fingerprints, retinal patterns, voice prints, and facial geometry.

Central Processing Unit (CPU)

The primary processor of a computer comprising the Control Unit (CU) and the Arithmetic and Logic Unit (ALU), responsible for governing the fetch-execute cycle.

Fetch-Execute Cycle

The operational sequence managed by the CPU in which computer instructions are fetched from memory, decoded into machine-understandable commands, and executed.

Arithmetic and Logic Unit (ALU)

The CPU subcomponent that carries out arithmetic calculations ($+,-,\times,/$) and logical evaluations ($<, >, =, <>, \text{AND}, \text{OR}$).

Control Unit (CU)

The CPU subcomponent that directs internal processor operations, controls information transfer across system components, and decodes instruction streams.

Booting Up

The computer startup process where the BIOS instructions in ROM are read and necessary operating system programs are loaded into RAM.

IPOS Cycle

The four fundamental stages of computer data handling: Input (entering raw data), Processing (computing and logical operations), Output (generating results), and Storage (retaining data).

Supercomputer

The most powerful, physically massive, and expensive category of computers, deployed in institutions like NASA for space exploration, weather forecasting, and intensive scientific computations.

Titan (Supercomputer)

A high-performance supercomputer installed at the Oak Ridge National Laboratory in the United States.

Tianhe-2

A supercomputer developed by China's National University of Defense Technology, recognized as one of the world's most powerful computing systems.

Mainframe Computer

A high-capacity, highly reliable computer server designed to support large databases, vast I/O devices, and thousands of concurrent users executing mission-critical enterprise transactions.

IBM Z

IBM's enterprise line of mainframe computers spanning from the z900 in 2000 to the z15 in September 2019, engineered with redundant architectures for zero downtime and capable of executing up to 1 trillion web transactions per day.

Minicomputer

A mid-sized computing system prevalent in the 1960s and 1970s that was smaller than a mainframe but larger than a personal computer, now considered obsolete.

Microcomputer

A computer that operates using a single-chip microprocessor as its CPU, designed for individual personal use (e.g., desktop PCs, laptops, and smartphones).

Embedded Computer

A dedicated computer system with industrial-grade components integrated directly into a larger machine to execute specific, predetermined functions (e.g., in cars, GPS units, and washing machines).

Data Validation

An automated error-checking check performed by computer software during data entry to ensure input conforms to specified criteria and acceptable data types.

Type Check

A validation check ensuring that entered data matches the expected data type, such as confirming only alphabetic letters are entered into a name field.

Range Check

A validation check that tests numerical entries against predefined upper and lower boundaries (e.g., verifying age falls within 16 and 17).

Consistency Check

A validation check that evaluates two or more related data fields to ensure they do not contradict each other (e.g., verifying entered age matches the provided birthdate).

Reasonableness Check

A validation check that confirms entered data is sensible and realistic within real-world constraints (e.g., confirming a sibling count is not 1.52 million).

Presence Check

A validation rule that verifies a mandatory field has not been left empty by the user during data entry.

Data Verification

A quality assurance process that checks whether entered or transferred data matches the source document exactly, without validating whether the data itself is sensible.

Dual Data Entry

A verification technique where the same source document data is typed in independently by two separate operators and automatically cross-compared for discrepancies.

Source Document

An original physical or hardcopy document containing original data used during the initial data entry stage, such as a driver's license application form.

Turnaround Document

A physical computer-produced document that serves as output at one stage and is later returned to serve as an input document, such as a tear-off utility bill payment slip.

System Software

The foundational software suite (including operating systems, device drivers, firmware, and utility tools) that manages computer hardware resources and facilitates application execution.

Application Software

End-user programs designed to carry out specific productive tasks, such as word processors, spreadsheets, graphics software, and web browsers.

General-Purpose Software

Commercial off-the-shelf application programs built by professional developers to handle broad, common tasks across any industry (e.g., Microsoft Word, Excel).

Integrated Software

A bundled software suite of multiple complementary application programs packaged and sold together, sharing common interfaces and effortless inter-application data exchange (e.g., Microsoft Office 365).

Custom-Written Software

Tailor-made software contracted to and developed by professional programmers or software houses specifically to meet unique business requirements.

Macro

A sequence of coded instructions embedded in a general-purpose application (such as Excel or Word) that automates repetitive tasks to create customized software.

Specialised Software

Software engineered for narrow, specialized domains and tasks rather than general business use, such as CAD/CAE architectural tools and medical diagnostic expert systems.

Pivot Table

An interactive statistics table in spreadsheet programs that summarizes, sorts, groups, counts, totals, or averages complex datasets by dynamically reorganizing rows and columns.

VLOOKUP

An Excel function that searches vertically down the leftmost column of a defined table range for a matching lookup value and returns the data from a designated column in that row.

Column Index Number (VLOOKUP)

The integer argument in a VLOOKUP formula designating which column of the table range contains the value to be retrieved and returned.

Range Lookup Parameter (VLOOKUP)

The final Boolean argument in a VLOOKUP formula; setting it to FALSE mandates an exact match lookup, returning an #N/A error if the exact value cannot be found.