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.]] A spreadsheet is a rectangular table (or grid) of information, often Financial information. The word came from "spread" in its sense of a newspaper or magazine item (text and/or graphics) that covers two facing pages, extending across the center fold and treating the two pages as one large one. The compound word "spread-sheet" came to mean the format used to present Bookkeeping Ledgers —with columns for categories of expenditures across the top, invoices listed down the left margin, and the amount of each payment in the cell where its row and column intersect—which were traditionally a "spread" across facing pages of a bound ledger (book for keeping accounting records) or on oversized sheets of paper ruled into rows and columns in that format and approximately twice as wide as ordinary paper. HISTORY Early implementations Batch spreadsheets One of the first commercial uses of Computer s was in processing Payroll and other financial records, so the programs (and, indeed, the Programming Language s themselves) were designed to generate reports in the standard "spreadsheet" format bookkeepers and Accountant s used. As computers became more available and affordable in the last quarter of the 20th century, more Software became available for them, and programs to keep financial records and generate spreadsheet reports were always in demand. Those spreadsheet programs can be used to Tabulate many kinds of information, not just financial records, so the term "spreadsheet" has developed a more general meaning as information presented in a rectangular table, usually generated by a computer. The concept of an electronic spreadsheet was outlined in the 1961 paper "Budgeting Models and System Simulation" by Richard Mattessich. Some credit for the computerized spreadsheet perhaps belongs to Rene K. Pardo and Remy Landau, who filed on some of the related Algorithms in 1970. While the patent was initially rejected by the patent office as being a purely mathematical invention, Pardo and Landau won a court case in 1983 establishing that "something does not cease to become patentable merely because the point of novelty is in an algorithm." This case helped establish the viability of Software Patent s. Autoplan/Autotab In 1968, three former employees from the General Electric computer company headquartered in Phoenix, Arizona set out to start their own software development house. A. Leroy Ellison, Harry N. Cantrell, and Russell E. Edwards found themselves doing a large number of calculations when making tables for the business plans that they were presenting to venture capitalists. They decided to save themselves a lot of effort and wrote a computer program that produced their tables for them. This program, originally conceived as a simple utility for their personal use, would turn out to be the first software product offered by the company that would become known as Capex Corporation . The program ran on GE’s Time-sharing service and was dubbed "AutoPlan". Soon afterward, a version that ran on IBM Mainframe s was introduced under the name "'''AutoTab'''". ( National CSS offered a similar product, CSSTAB, which had a moderate timesharing user base by the early 70s. A major application was opinion research tabulation.) AutoPlan/AutoTab was not a WYSIWYG Interactive spreadsheet program. It was more like a simple scripting language for spreadsheets. The user defined the names and labels for the rows and columns, then the formulas that defined each row or column. The basic processing was as follows; if row formulas were defined, the program Loop ed through the formulae for each column from left to right; if column formulae were defined, the program looped through the formulae for each row from top to bottom. There were many refinements available. Capex Corporation was swallowed up by Computer Associates in 1982, the first link in CA’s long chain of acquisitions. AutoPlan had pretty much disappeared along with the GE timesharing service, and AutoTab was at best a minor product by then. AutoTab was never offered under the CA company name. Interactive spreadsheets It was not until the ready availability of Visual Display Unit s ("VDU's") that fully interactive spreadsheets became possible. Earlier implementations were mainly designed around batch programs. In the early 1970s text based VDU's began to be used as input/output devices for interactive transaction processes. It was several years later before full function Graphic User Interface s were widely available for new user interface paradigms such as spreadsheets. A number of innovative timesharing applications were built in 60s, 70s, and early 80s that anticipated some of the user interface elements eventually popularized in PC spreadsheets. Some were developed by the commercial computer timesharing industry; others were academic projects; and yet others were built by large computer users to meet in-house needs.One example cited recently in Wikipedia is the CICS -based Works Records System built by Imperial Chemical Industries in the early 1970s. Other innovative approaches to end-user computing were being pursued at Xerox PARC , MIT , Citibank , National CSS , and IBM . The lack of on-line historical material relating to such systems, and their limited coverage in academic and commercial publications, makes it hard to assess their level of innovation and ultimate impact. Throughout the industry's history, there have always been clever engineers working to build better user interfaces, and few development projects have occurred in a vacuum without inspiration from prior art. Nevertheless, the history of spreadsheets seems most strongly influenced by the handful of products and technologies that became well-known. An example of an early "industrial weight" spreadsheet was APLDOT, developed in 1976 at the . APLDOT was dubbed a "spreadsheet" because financial analysts and strategic planners used it to solve the same problems they addressed with paper spreadsheet pads. All software development was in the public domain; the software system underwent a court challenge in ''US Government vs Penn Central et al.'' in 1978 and 1979. VisiCalc The spreadsheet concept became widely known in the late 1970s and early 1980s because of Dan Bricklin 's implementation of VisiCalc . Bricklin has spoken of watching his university professor create a table of calculation results on a blackboard. When the professor found an error, he had to tediously erase and rewrite a number of sequential entries in the table, triggering Bricklin to think that he could replicate the process on a computer, using the blackboard as the model to view results of underlying formulas. His idea became VisiCalc , the first Application that turned the Personal Computer from a hobby for computer enthusiasts into a business tool. VisiCalc went on to become the first " Killer App ", an application that was so compelling, people would buy a particular computer just to own it. In this case the computer was the Apple II , and VisiCalc was no small part in that machine's success. The program was later Ported to a number of other early computers, notably CP/M machines, the Atari 8-bit Family and various Commodore platforms. Nevertheless, VisiCalc remains best known as "an Apple II program". The acceptance of the IBM PC following its introduction in August, 1981, began slowly, because most of the programs available for it were ports from other 8-bit platforms. Things changed dramatically with the introduction of Lotus 1-2-3 in November, 1982, and release for sale in January, 1983. It became that platform's killer app, and drove sales of the PC due to the improvements in speed and graphics compared to VisiCalc. VisiCorp was unable to respond competitively, and disappeared within a few years. Lotus 1-2-3, Quattro, and Microsoft Excel Lotus 1-2-3, along with its erstwhile competitor Borland Quattro , soon displaced VisiCalc; but they in turn faced a similar fate as Microsoft expanded its control of the PC desktop. Microsoft had been developing Excel on the Macintosh platform for several years at this point, where it had developed into a fairly powerful system. A port of Excel to Windows 2.0 resulted in a fully functional Windows spreadsheet. The more robust Windows 3.x platforms of the early 1990s made it possible for Excel to take market share from Lotus. By the time Lotus responded with usable Windows products, Microsoft had started compiling their Office suite. To this day, Microsoft continues to dominate the industry. OpenOffice OpenOffice.org Calc is an open-source alternative to Microsoft Excel . Calc can open Excel's files. Calc's files can be converted to Excel. Other products A number of companies have attempted to break into the spreadsheet market with programs based on very different paradigms. Lotus introduced what is likely the most successful example, Lotus Improv , which saw some commercial success, notably in the financial world where its powerful Data Mining capabilities remain well respected to this day. Spreadsheet 2000 attempted to dramatically simplify formula construction, but was generally not successful. Stories attempted to make it easier to deal with 3-D blocks of data (as opposed to the 2-D nature of most spreadsheets), but appears to have seen little or no use. CONCEPTS Cells A "cell" can be thought of as a box or "pigeon hole" for holding Data . A single cell is usually referenced by its column and row (A2 would represent the cell below containing the value 10). Its physical size can usually be tailored for its content by dragging its height or width at box intersections (or for entire columns or rows by dragging the column or rows headers). An Array of cells is called a "sheet" or "worksheet". It is analogous to an array of Variable s in a conventional Computer Program (although certain unchanging values, once entered, could be considered, by the same analogy, Constant s). In most implementations, many worksheets may be located within a single spreadsheet. A worksheet is simply a subset of the spreadsheet divided for the sake of clarity. Functionally, the spreadsheet operates as a whole and all cells operate as Global Variable s within the spreadsheet. A cell may contain a Value or a Formula , by convention usually beginning with = sign, or it may simply be left empty. Values A value can be entered from the computer keyboard by directly typing into the cell itself. Alternatively, a value can be based on a formula (see below), which might perform a calculation, display the current date or time, or retrieve external data such as a stock quote or a database value. The Spreadsheet ''Value Rule'' |
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