Shopping on line can be easy, simple and save you lots of money. It can also take a lot of your time, frustrate you, and result in unwanted purchases. Now the same can be said for regular high street shopping, but with the vast opportunity presented by the Internet it will pay you to spend a few minutes reading this and understanding how to better optimize your Spreadsheet shopping experience:
1. Compare - without doubt the biggest advantage that the Spreadsheet offers shoppers today is the ability to compare thousands of Spreadsheet at a time. This is a great thing, but not necessarily all the time! Too much can be daunting at times so take advantage of the great comparison sites and where possible let them do the hard work for you.
2. Research - if it has been said it will be on the internet. Ignorance is no longer a justifiable reason for buying the wrong thing. Take the time to research in detail everything that you could possible want to know about
3. Testimonials - don't know anybody that has bought a Spreadsheet? Wrong! If the Spreadsheet is good the internet will let you know. Use the Internet as a friend and get testimonials before you buy.
4. Questions - Got a question about Spreadsheet then search the Forums, FAQ's, Blogs etc. Don't be afraid to ask .....
5. Reputation - Never heard of the company selling Spreadsheet? Don't worry, no reason why you should know every company in the world, but you know someone that does! Use the internet to find out what people are saying about Spreadsheet and build up a picture of their reputation for sales, returns, customer service, delivery etc.
6. Returns - still worried that even after all of the above your Spreadsheet wont be what you want? Check out the returns policy. There is so much competition now that someone, somewhere is bound to offer the terms that you are comfortable with.
7. Feedback - happy with your Spreadsheet then let people know, after all you are depending on others people input in your buying decision, so why not give a little back.
8. Security - check for the yellow padlock on the Spreadsheet site before you buy, and the s after http:/ /i.e. https:// = a secure site
9. Contact - got a question about Spreadsheet, or want to leave a comment then check out the sites contact page. Reputable companies have them and respond.
10. Payment - ready to pay for your Spreadsheet, then use your credit card or PayPal! Be aware of companies that don't accept them, there may be genuine reasons but given the huge amount of choice you have when buying online there is no reason at all not to buy via credit card or PayPal.
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 General ledger—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
computers was in processing
payroll and other financial records, so the programs (and, indeed, the programming languages themselves) were designed to generate reports in the standard "spreadsheet" format bookkeepers and accountants 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
Table (information) 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 patents.
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 mainframes 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 Control flow#Loopsed 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 units ("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 interfaces 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, Massachusetts Institute of Technology, Citibank, National CSS, and
International Business Machines. 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 United States Railway Association on an IBM 360/91, running at The Johns Hopkins University Applied Physics Laboratory in Laurel, MD. portal.acm.org – APLDOT The application was used successfully for many years in developing such applications as financial and costing models for the US Congress and for
Conrail. 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 software 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 International 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 Microsoft Excel on the
Apple 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
Microsoft 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 (spreadsheet) 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.
- A list of old spreadsheet software
- Boeing Calc 3D
- Improv
- Javlin
- Lotus Jazz for Macintosh
- Lucid 3D
- MultiPlan
- PowerStep for NeXT Step
- Quattro Pro
- Silk
- SuperCalc
- Surpass
- Symphony
- TWIN
- VP Planner
- Wingz for Macintosh
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).
{]ed !! Multiplied|-!02 !! 10 || 20 ||
30 || 200|}
An
array of cells is called a "sheet" or "worksheet". It is analogous to an array of
variables in a conventional
computer program (although certain unchanging values, once entered, could be considered, by the same analogy,
constants). 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 variables within the spreadsheet.
A cell may contain a Value (computer science) 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 RuleComputer scientist
Alan Kay used the term
value rule to summarize a spreadsheet's operation: a cell's value relies solely on the formula the user has typed into the cell – Value Rule.
The formula may rely on the value of other cells, but those cells are likewise restricted to user-entered data or formulas. There are no 'side effects' to calculating a formula: the only output is to display the calculated result inside its occupying cell. There is no natural mechanism for permanently modifying the contents of a cell unless the user manually modifies the cell's contents. In the context of programming languages, this yields a limited form of first-order
functional programming – spreadsheets as functional programming.
Real time update
A standard of speadsheets since the mid 80s, this feature eliminates the need to manually tell the spreadsheet to recalculate values. Earlier speadsheets required manual calls to recalculate as calculation times hindered data entry speed.
Formula
When a cell contains a
formula, it often contains references to other cells. Such a cell reference is a type of variable. Its value is the value of the referenced cell or some derivation of it. If that cell in turn references other cells, the value depends on the values of those.
By convention, the left hand side, of what is normally considered a formula, is omitted and assumed to be the cell itself.
In the above example the formula in the cell "C2" might be either:-
- =A2+B2 or
- =SUM(A2:B2) (A2 is start of a cell range and B2 its end).
A formula identifies the calculation needed to place the result in the cell it is contained within. A cell containing a formula therefore has two display components; the formula itself and the resulting value. The formula is normally only shown when the cell is selected by "clicking" the mouse over a particular cell; otherwise it contains the result of the calculation (in this case 30). (A common error in spreadsheet usage is when a cell, previously holding a formula, is accidentally directly over-keyed by a value from the keyboard. Most modern spreadsheets allow selective "locking" of cells to prevent this, though many users do not take advantage of this feature.)
The available options for valid formulae depends on the particular spreadsheet implementation but, in general, most arithmetic operations and quite complex nested conditional operations can be performed by most of today's commercial spreadsheets. Modern implementations also offer functions to access remote data and applications.
A formula may contain a condition (or nested conditions) - with or without an actual calculation - and is sometimes used purely to identify and
highlight errors. In the example below, it is assumed the sum of a column of percentages (A1 through A6) is tested for validity and an explicit message put into the adjacent right hand cell with a simple pointer graphic to the total to the left.
=IF(sum(A1:A6) > 100%, "{{cite web|url=http://panko.shidler.hawaii.edu/ssr/Mypapers/whatknow.htm|title=What We Know About Spreadsheet Errors|accessdate=2006-09-22|author=Raymond R. Panko|date=2005-01-->:
- While spreadsheets are effective at certain tasks, they are sometimes used for tasks that they are not suited to. Is Excel Budgeting a Mistake?]
Excel's critics say that Excel is fundamentally unsuited for budgeting, forecasting, and other activities that involve collaboration or consolidation. Are they correct?http://www.cs.uiowa.edu/~jcryer/JSMTalk2001.pdf Problems With Using Microsoft
Excel for Statistics Spreadsheet Addiction
- Lack of auditing and revision control. This makes it difficult to determine who changed what and when. This can cause problems with regulatory compliance, among other things.
- Lack of Computer security. Generally, if one has permission to open a spreadsheet, one has permission to modify any part of it. This, combined with the lack of auditing above, can make it easy for someone to commit fraud.
- Lack of Concurrency (computer science). Unlike databases, spreadsheets typically allow only one user to be making changes at any given time.
- Because they are loosely structured, it is easy for someone to introduce an error, either accidentally or intentionally, by entering information in the wrong place or expressing dependencies among cells (such as in a formula) incorrectly. Excel spreadsheets in School budgeting - a cautionary tale (2001) Public reports of spreadsheet errors collated by the European Spreadsheet Risks Interest Group (EuSpRIG).
- The results of a formula (example "=A1*B1") applies only to a single cell (that is, the cell the formula is actually located in - in this case perhaps C1), even though it can "extract" data from many other cells, and even real time dates and actual times. This means that to cause a similar calculation on an array of cells, an almost identical formula (but residing in its own "output" cell) must be repeated for each row of the "input" array.This differs from a "formula" in a conventional computer program which would typically have one calculation which would then apply to all of the input in turn. With current spreadsheets, this forced repetition of near identical formulae can have detrimental consequences from a quality assurance standpoint and is often the cause of many spreadsheet errors. This last problem could be solved conceptually, simply by permitting the specification of a new category of "spatially independent" formula, allowing the "left hand" (target) of the formula to be entered combined with use of "indexed cell addressing" of the generic form:-
WHILE COUNT(A1:A20) > 0), C(i) = A(i)*B(i) where i=incremented row number (1-20)
This theoretical category of formula could reside anywhere within the spreadsheet since its target cell(s) are specified independently of their location in the spreadsheet.(However, for clarity, the "
cloned" formula could optionally be shown in each target cell, any change to one affecting all its clones automatically, thereby reducing errors).
or, to conform more to current "spreadsheet like" syntax perhaps:-=IF(COUNT(A1:A20) > 0, A(i)*B(i),"") where 2nd parameter represents the formula
to be applied to each occurrence - but entered only in the first cell, the rest of them displaying the cloned formula.
With the recent advent of remote data update of cells, the need to specify conditional formula of this type will assume a new urgency since the precise contents and extents of external spreadsheets may not be fully discernable before execution.
While there are built-in and Third-party developer tools for desktop spreadsheet applications that address some of these shortcomings, awareness of these is generally low, and usage lower still. However, many of these earlier shortcomings can be handled by online spreadsheets such as EditGrid and
Google Docs.
Web based spreadsheets
The advent of advanced World Wide Web technologies, such as
Ajax (programming) and XML user interface language, circa 2005 has propelled the emergence of a new generation of
List of online spreadsheets. Equipped with a
rich Internet application user experience, many of the web based online spreadsheets
boast the same features seen in desktop spreadsheet applications. Some already surpass them, offering real time updates from remote sources such as stock prices and currency
exchange rates.
See also
References
External links
General information
- A Brief History of Spreadsheets by D.J. Power
- A Spreadsheet Programming article on DevX
- comp.apps.spreadsheets FAQ by Russell Schulz
- Develop Training Simulations with Excel
- Extending the Concept of Spreadsheet by Jocelyn Paine
- Linux Spreadsheets by Christopher Browne; much general information on spreadsheets, and some on related Linux issues
- Spreadsheets category on the Open Directory Project
- Spreadsheet - Its First Computerization (1961-1964) by Richard Mattessich
- "Spreadsheet Wars" - A classic video showing spreadsheet vendors going head-to-head in the late 80's .
- CICS history and introduction of IBM 3270 by Bob Yelavich
- Autoplan & Autotab article by Creative Karma
Research organisations
- European Spreadsheet Risks Interest Group (EuSpRIG)
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
General ledger—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
computers was in processing
payroll and other financial records, so the programs (and, indeed, the
programming languages themselves) were designed to generate reports in the standard "spreadsheet" format bookkeepers and
accountants 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
Table (information) 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 patents.
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 mainframes 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 Control flow#Loopsed 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 units ("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 interfaces 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,
Massachusetts Institute of Technology,
Citibank, National CSS, and
International Business Machines. 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 United States Railway Association on an IBM 360/91, running at The Johns Hopkins University Applied Physics Laboratory in Laurel, MD. portal.acm.org – APLDOT The application was used successfully for many years in developing such applications as financial and costing models for the US Congress and for Conrail. 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 software 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 International 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
Microsoft Excel on the
Apple 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 Microsoft 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 (spreadsheet) 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.
- A list of old spreadsheet software
- Boeing Calc 3D
- Improv
- Javlin
- Lotus Jazz for Macintosh
- Lucid 3D
- MultiPlan
- PowerStep for NeXT Step
- Quattro Pro
- Silk
- SuperCalc
- Surpass
- Symphony
- TWIN
- VP Planner
- Wingz for Macintosh
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).
{]ed !! Multiplied|-!02 !! 10 || 20 ||
30 || 200|}
An array of cells is called a "sheet" or "worksheet". It is analogous to an array of
variables in a conventional computer program (although certain unchanging values, once entered, could be considered, by the same analogy, constants). 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 variables within the spreadsheet.
A cell may contain a
Value (computer science) 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 RuleComputer scientist Alan Kay used the term
value rule to summarize a spreadsheet's operation: a cell's value relies solely on the formula the user has typed into the cell – Value Rule.
The formula may rely on the value of other cells, but those cells are likewise restricted to user-entered data or formulas. There are no 'side effects' to calculating a formula: the only output is to display the calculated result inside its occupying cell. There is no natural mechanism for permanently modifying the contents of a cell unless the user manually modifies the cell's contents. In the context of programming languages, this yields a limited form of first-order
functional programming – spreadsheets as functional programming.
Real time update
A standard of speadsheets since the mid 80s, this feature eliminates the need to manually tell the spreadsheet to recalculate values. Earlier speadsheets required manual calls to recalculate as calculation times hindered data entry speed.
Formula
When a cell contains a
formula, it often contains references to other cells. Such a cell reference is a type of variable. Its value is the value of the referenced cell or some derivation of it. If that cell in turn references other cells, the value depends on the values of those.
By convention, the left hand side, of what is normally considered a formula, is omitted and assumed to be the cell itself.
In the above example the formula in the cell "C2" might be either:-
- =A2+B2 or
- =SUM(A2:B2) (A2 is start of a cell range and B2 its end).
A formula identifies the
calculation needed to place the result in the cell it is contained within. A cell containing a formula therefore has two display components; the formula itself and the resulting value. The formula is normally only shown when the cell is selected by "clicking" the mouse over a particular cell; otherwise it contains the result of the calculation (in this case 30). (A common error in spreadsheet usage is when a cell, previously holding a formula, is accidentally directly over-keyed by a value from the keyboard. Most modern spreadsheets allow selective "locking" of cells to prevent this, though many users do not take advantage of this feature.)
The available options for valid formulae depends on the particular spreadsheet implementation but, in general, most arithmetic operations and quite complex nested conditional operations can be performed by most of today's commercial spreadsheets. Modern implementations also offer functions to access remote data and applications.
A formula may contain a condition (or nested conditions) - with or without an actual calculation - and is sometimes used purely to identify and
highlight errors. In the example below, it is assumed the sum of a column of percentages (A1 through A6) is tested for validity and an explicit message put into the adjacent right hand cell with a simple pointer graphic to the total to the left.
=IF(sum(A1:A6) > 100%, "{{cite web|url=http://panko.shidler.hawaii.edu/ssr/Mypapers/whatknow.htm|title=What We Know About Spreadsheet Errors|accessdate=2006-09-22|author=Raymond R. Panko|date=2005-01-->:
- While spreadsheets are effective at certain tasks, they are sometimes used for tasks that they are not suited to. Is Excel Budgeting a Mistake?]
Excel's critics say that Excel is fundamentally unsuited for budgeting, forecasting, and other activities that involve collaboration or consolidation. Are they correct?http://www.cs.uiowa.edu/~jcryer/JSMTalk2001.pdf Problems With Using Microsoft
Excel for Statistics Spreadsheet Addiction
- Lack of auditing and revision control. This makes it difficult to determine who changed what and when. This can cause problems with regulatory compliance, among other things.
- Lack of Computer security. Generally, if one has permission to open a spreadsheet, one has permission to modify any part of it. This, combined with the lack of auditing above, can make it easy for someone to commit fraud.
- Lack of Concurrency (computer science). Unlike databases, spreadsheets typically allow only one user to be making changes at any given time.
- Because they are loosely structured, it is easy for someone to introduce an error, either accidentally or intentionally, by entering information in the wrong place or expressing dependencies among cells (such as in a formula) incorrectly. Excel spreadsheets in School budgeting - a cautionary tale (2001) Public reports of spreadsheet errors collated by the European Spreadsheet Risks Interest Group (EuSpRIG).
- The results of a formula (example "=A1*B1") applies only to a single cell (that is, the cell the formula is actually located in - in this case perhaps C1), even though it can "extract" data from many other cells, and even real time dates and actual times. This means that to cause a similar calculation on an array of cells, an almost identical formula (but residing in its own "output" cell) must be repeated for each row of the "input" array.This differs from a "formula" in a conventional computer program which would typically have one calculation which would then apply to all of the input in turn. With current spreadsheets, this forced repetition of near identical formulae can have detrimental consequences from a quality assurance standpoint and is often the cause of many spreadsheet errors. This last problem could be solved conceptually, simply by permitting the specification of a new category of "spatially independent" formula, allowing the "left hand" (target) of the formula to be entered combined with use of "indexed cell addressing" of the generic form:-
WHILE COUNT(A1:A20) > 0), C(i) = A(i)*B(i) where i=incremented row number (1-20)
This theoretical category of formula could reside anywhere within the spreadsheet since its target cell(s) are specified independently of their location in the spreadsheet.(However, for clarity, the "cloned" formula could optionally be shown in each target cell, any change to one affecting all its clones automatically, thereby reducing errors).
or, to conform more to current "spreadsheet like" syntax perhaps:-=IF(COUNT(A1:A20) > 0, A(i)*B(i),"") where 2nd parameter represents the formula
to be applied to each occurrence - but entered only in the first cell, the rest of them displaying the cloned formula.
With the recent advent of remote data update of cells, the need to specify conditional formula of this type will assume a new urgency since the precise contents and extents of external spreadsheets may not be fully discernable before execution.
While there are built-in and
Third-party developer tools for desktop spreadsheet applications that address some of these shortcomings, awareness of these is generally low, and usage lower still. However, many of these earlier shortcomings can be handled by online spreadsheets such as EditGrid and Google Docs.
Web based spreadsheets
The advent of advanced World Wide Web technologies, such as
Ajax (programming) and XML user interface language, circa 2005 has propelled the emergence of a new generation of List of online spreadsheets. Equipped with a
rich Internet application user experience, many of the web based online spreadsheets boast the same features seen in desktop spreadsheet applications. Some already surpass them, offering real time updates from remote sources such as stock prices and currency exchange rates.
See also
References
External links
General information
- A Brief History of Spreadsheets by D.J. Power
- A Spreadsheet Programming article on DevX
- comp.apps.spreadsheets FAQ by Russell Schulz
- Develop Training Simulations with Excel
- Extending the Concept of Spreadsheet by Jocelyn Paine
- Linux Spreadsheets by Christopher Browne; much general information on spreadsheets, and some on related Linux issues
- Spreadsheets category on the Open Directory Project
- Spreadsheet - Its First Computerization (1961-1964) by Richard Mattessich
- "Spreadsheet Wars" - A classic video showing spreadsheet vendors going head-to-head in the late 80's .
- CICS history and introduction of IBM 3270 by Bob Yelavich
- Autoplan & Autotab article by Creative Karma
Research organisations
- European Spreadsheet Risks Interest Group (EuSpRIG)
spreadsheet from FOLDOC
spreadsheet < application, tool > (Or rarely "worksheet") A type of application program which manipulates numerical and string data in rows and columns of cells.
Spreadsheet - Wikipedia, the free encyclopedia
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