A reference card or reference sheet (or quick reference card) or crib sheet is a concise bundling of condensed notes about a specific topic, such as mathematical formulas [1] to calculate area/volume, or common syntactic rules and idioms of a particular computer platform, application program, or formal language. It serves as an ad hoc memory aid for an experienced user. [2]
In spite of what the name reference card may suggest, such as a 3x5 index card (8 cm × 13 cm), the term also applies to sheets of paper or online pages, as in the context of programming languages or markup languages. However, this concept is now being adopted to portray concise information in many other fields.
As in the examples below, reference cards are typically one to a few pages in length. Pages are organized into one or more columns. Across the columns, the reference is split into sections and organized by topic. Each section contains a list of entries, with each entry containing a term and its description and usage information. Terms might include keywords, syntactic constructs, functions, methods, or macros in a computer language. In a reference card for a program with a graphical user interface, terms may include menu entries, icons or key combinations representing program actions.
Due to its logical structure and conciseness, finding information in a reference card is trivial for humans and requires no computer interaction. It is therefore convenient for a user to print out a reference card. While reference cards can be printed on card stock, it is common to print them on ordinary printer paper. With the advent of portable electronic devices that can display documents, digital reference cards stored in PDF or HTML formats have become more common. This is in contrast to user guides, which tend to be rather long and verbose and which have (in comparison to reference cards) a lower information density
Fortran is a general-purpose, compiled imperative programming language that is especially suited to numeric computation and scientific computing.
A punched card is a piece of stiff paper that holds digital data represented by the presence or absence of holes in predefined positions. Punched cards were once common in data processing applications or to directly control automated machinery.
A spreadsheet is a computer application for organization, analysis, and storage of data in tabular form. Spreadsheets were developed as computerized analogs of paper accounting worksheets. The program operates on data entered in cells of a table. Each cell may contain either numeric or text data, or the results of formulas that automatically calculate and display a value based on the contents of other cells. A spreadsheet may also refer to one such electronic document.
TeX, stylized within the system as TeX, is a typesetting system which was designed and mostly written by Donald Knuth and released in 1978. TeX is a popular means of typesetting complex mathematical formulae; it has been noted as one of the most sophisticated digital typographical systems.
A text editor is a type of computer program that edits plain text. Such programs are sometimes known as "notepad" software, following the naming of Microsoft Notepad. Text editors are provided with operating systems and software development packages, and can be used to change files such as configuration files, documentation files and programming language source code.
Desktop publishing (DTP) is the creation of documents using page layout software on a personal ("desktop") computer. It was first used almost exclusively for print publications, but now it also assists in the creation of various forms of online content. Desktop publishing software can generate layouts and produce typographic-quality text and images comparable to traditional typography and printing. Desktop publishing is also the main reference for digital typography. This technology allows individuals, businesses, and other organizations to self-publish a wide variety of content, from menus to magazines to books, without the expense of commercial printing.
GNU TeXmacs is a scientific word processor and typesetting component of the GNU Project. It was inspired by TeX and GNU Emacs, though it shares no code with those programs. TeXmacs does use TeX fonts. It is written and maintained by Joris van der Hoeven and a group of developers. The program produces structured documents with a WYSIWYG user interface. New document styles can be created by the user. The editor provides high-quality typesetting algorithms and TeX and other fonts for publishing professional looking documents.
A library catalog is a register of all bibliographic items found in a library or group of libraries, such as a network of libraries at several locations. A catalog for a group of libraries is also called a union catalog. A bibliographic item can be any information entity that is considered library material, or a group of library materials, or linked from the catalog as far as it is relevant to the catalog and to the users (patrons) of the library.
BibTeX is reference management software for formatting lists of references. The BibTeX tool is typically used together with the LaTeX document preparation system. Within the typesetting system, its name is styled as . The name is a portmanteau of the word bibliography and the name of the TeX typesetting software.
Job Control Language (JCL) is a name for scripting languages used on IBM mainframe operating systems to instruct the system on how to run a batch job or start a subsystem.
In computing, spooling is a specialized form of multi-programming for the purpose of copying data between different devices. In contemporary systems, it is usually used for mediating between a computer application and a slow peripheral, such as a printer. Spooling allows programs to "hand off" work to be done by the peripheral and then proceed to other tasks, or to not begin until input has been transcribed. A dedicated program, the spooler, maintains an orderly sequence of jobs for the peripheral and feeds it data at its own rate. Conversely, for slow input peripherals, such as a card reader, a spooler can maintain a sequence of computational jobs waiting for data, starting each job when all of the relevant input is available; see batch processing. The spool itself refers to the sequence of jobs, or the storage area where they are held. In many cases, the spooler is able to drive devices at their full rated speed with minimal impact on other processing.
The IBM 1130 Computing System, introduced in 1965, was IBM's least expensive computer at that time. A binary 16-bit machine, it was marketed to price-sensitive, computing-intensive technical markets, like education and engineering, succeeding the decimal IBM 1620 in that market segment. Typical installations included a 1 megabyte disk drive that stored the operating system, compilers and object programs, with program source generated and maintained on punched cards. Fortran was the most common programming language used, but several others, including APL, were available.
Starting at the end of the nineteenth century, well before the advent of electronic computers, data processing was performed using electromechanical machines called unit record equipment, electric accounting machines (EAM) or tabulating machines. Unit record machines came to be as ubiquitous in industry and government in the first two-thirds of the twentieth century as computers became in the last third. They allowed large volume, sophisticated data-processing tasks to be accomplished before electronic computers were invented and while they were still in their infancy. This data processing was accomplished by processing punched cards through various unit record machines in a carefully choreographed progression. This progression, or flow, from machine to machine was often planned and documented with detailed flowcharts that used standardized symbols for documents and the various machine functions. All but the earliest machines had high-speed mechanical feeders to process cards at rates from around 100 to 2,000 per minute, sensing punched holes with mechanical, electrical, or, later, optical sensors. The operation of many machines was directed by the use of a removable plugboard, control panel, or connection box. Initially all machines were manual or electromechanical. The first use of an electronic component was in 1937 when a photocell was used in a Social Security bill-feed machine. Electronic components were used on other machines beginning in the late 1940s.
A keypunch is a device for precisely punching holes into stiff paper cards at specific locations as determined by keys struck by a human operator. Other devices included here for that same function include the gang punch, the pantograph punch, and the stamp.
The IBM System/3 was an IBM midrange computer introduced in 1969, and marketed until 1985. It was produced by IBM Rochester in Minnesota as a low-end business computer aimed at smaller organizations that still used IBM 1400 series computers or unit record equipment. The first member of what IBM refers to as their "midrange" line, it also introduced the RPG II programming language. It is the first ancestor in the product line whose current version is the IBM i series and includes the highly successful AS/400.
A plugboard or control panel is an array of jacks or sockets into which patch cords can be inserted to complete an electrical circuit. Control panels are sometimes used to direct the operation of unit record equipment, cipher machines, and early computers.
A cheat sheet or crib sheet is a concise set of notes used for quick reference.
From the invention of computer programming languages up to the mid-1970s, most computer programmers created, edited and stored their programs line by line on punch cards.
Input/Output Control System (IOCS) is any of several packages on early IBM entry-level and mainframe computers that provided low level access to records on peripheral equipment. IOCS provides functionality similar to File Control Processor (FCP) in RCA 3301 Realcom Operating System, GEFRC in GECOS and Record Management Services (RMS) in DEC VAX/VMS.
The Symbolic Assembly Program (SAP) is an assembler program for the IBM 704 computer. It was written by Roy Nutt at United Aircraft Corporation, and was distributed by the SHARE user's group beginning in 1956 as the Share Assembly Program. SAP succeeded an earlier program called NYAP1, which it closely resembled, and became the standard assembler for 704 users. It "set the external form of an assembly language that was to be a model for all its successors and which persists almost unchanged to the present day."
Technicians and operators carried cards with commonly needed information culled from the many reference manuals for each computer. A “green card” in your shirt pocket announced that you were an assembly-language programmer.