The Turtle System Indicator contains a custom version of the classic Turtle Trader indicator. It implements both the main system (S1) and fail-safe system (S2) as described by the original Turtles. Notifications can also be enabled for trade signals.

HISTORY

The Turtle Trader legend began with a bet between two American millionaire commodities traders, Richard Dennis and his business partner, William (Bill) Eckhardt. Dennis believed that traders could be taught to be great. Eckhardt disagreed and thought that genetics were the determining factor and that skilled traders were born with an innate sense of timing and a gift for reading market trends.

In 1983, Richard Dennis put an advertisement in a few newspapers stating that he was seeking applicants to train in his proprietary trading concepts and that experience was unnecessary. The experiment started with a small group of people from diverse backgrounds. The group of traders were gathered into a large sparsely furnished room in downtown Chicago and for two weeks.

Dennis taught them the rudiments of futures trading. Most of the Turtles became profitable traders and made fortunes in the following years. It is said that the traders were called "Turtle" because Dennis had recently returned from Asia when he started the program. He says that he described the program to someone by saying, "We are going to grow traders just like they grow turtles in Singapore".

What happened in 1983-1984 became one of the most famous experiments in trading history. The program was a success. It showed that anyone with a good set of rules and sufficient funds could be successful.

INTRODUCTION

The Turtle trend following system was designed by Richard Dennis and William Eckhardt, and relies on breakouts of historical highs and lows to open and close trades. A breakout is defined as the price exceeding the high or low of a particular number of periods. For example, a 20-period breakout would be defined as price exceeding the high or low of the preceding 20 periods. It is the complete opposite of the "buy low and sell high" approach.

The

MAIN TURTLE TRADING RULE:

• T is trend periods value
• S is stop periods value

• Buy a 10-period breakout and close the trade when price action reaches a 5-period low. Note: T = 10, S = 5.
• Sell a 20-period breakout and close the trade when price action reaches a 10-period high. Note: T = 20, S = 10.

In this turtle trader indicator, the solid red and solid green lines are the trading lines, and the dotted lines are the exit lines. The original system is:

• Go long when the trading line turns green
• Go short when the trading line turns red
• Exit long positions when the price touches the exit line
• Exit short positions when the price touches the exit line

In this turtle trader indicator, entry and exit signals are displayed as arrows and dots. Original system is:

• Go long on green arrows
• Go short on red arrows
• Exit long positions when a green dot appears
• Exit short positions when a red dot appears

Recommended initial stop-loss is (2 * ATR) from the opening price. Default system parameters for trend periods and stop periods were S1(20, 10) and S2(55, 20).

I have altered the original turtle trader algorithm to get early entry signals and avoid random trend swings in highly volatile conditions. To do so, this indicator will only show a trend change when a bar actually closes above or below the current trend-line -instead of just touching it like a normal stop-loss order would do.

The down-side is that you can only detect trend changes when the last bar has already closed. Using the strict rules will allow the original turtle functionality to be used.

This indicator combines the channels indicator and the turtle trading indicator to represent the same period or the fail-safe trading system and get further signals if you have been stopped out. The important function about this indicator is that it actually checks if your last trade has been stopped out and gives further entry signals along the trend.

Both indicators implement trading alerts, enable or disable them at will depending on your trading setup.

ORIGINAL TURTLE RULES

To trade exactly like the original turtles did, you need to set up two indicators representing the main (S1) and the fail-safe (S2) system.

• S1: Set up the main indicator with S1_TurtleTrendPeriods = 20 and S1_TurtleStopPeriods = 10
• S2: Set up the fail-safe indicator with S2_TurtleTrendPeriods = 55 and S2_TurtleStopPeriods = 20 using a different color

The entry strategy using S1 is as follows:

• Buy 20-period breakouts using S1 only if last signaled trade was a loss.
• Sell 20-period breakouts using S1 only if last signaled trade was a loss.
• If last signaled trade by S1 was a win, you should not trade, regardless of the direction or if you traded last signal

The entry strategy using S2 is as follows:

• Buy 55-period breakouts only if you ignored last S1 signal and the market is rallying without you
• Sell 55-period breakouts only if you ignored last S1 signal and the market is plugging without you

The turtles had a progressive position sizing approach that boosted their winnings. Once a trading decision has been made you should:

• O1: Enter the market with 2% risk. Place SL (2 * ATR) from the opening price.
• O2: If position moves in your favor (0.5 * ATR), enter market with 2% risk and trail all stop loss (2 * ATR) from current price.
• O3: If position moves in your favor (0.5 * ATR), enter market with 2% risk and trail all stop loss (2 * ATR) from current price.
• O4: If position moves in your favor (0.5 * ATR), enter market with 2% risk and trail all stop loss (2 * ATR) from current price.
• Stop adding to positions when 4 positions have been taken.

The exit strategy is performed using the dotted line of the indicator:

• Exit longs taken using S1 when price action closes below a 10-period low
• Exit shorts taken using S1 when price action closes above a 10-period high
• Exit longs taken using S2 when price action closes below a 20-period low
• Exit shorts taken using S2 when price action closes above a 20-period high

The turtles had very strict money management too. Initial position risk was 2%, but it decreased according to the current drawdown(DD).

• If the account had a 10% DD, the risk for each trade should decrease a 20%
• If the account had a 20% DD, the risk for each trade should decrease a 40%.
• If the account had a 30% DD, the risk for each trade should decrease a 60%.
• So, if the account had N% DD, the risk for each trade should decrease N * 2%.

POSITION SIZING

The turtles used a volatility-based constant percentage risk position sizing algorithm. Their algorithm was very advanced for its time period. It normalized the dollar volatility of a position by adjusting the position size based on the dollar volatility of the market. This meant that a given position would tend to move up or down in a given day about the same amount in dollars term, when compared to positions in other markets regardless of the underlying volatility of the particular market.

This is true because positions in markets that moved up and down a large amount per contract would have an offset smaller number of contracts than positions in markets that had lower volatility.

This volatility normalization is very important because it means that different trades in different markets tend to have the same chance for a particular dollar loss or a particular dollar gain. This increased the effectiveness of the diversification of trading across many markets.

Even if the volatility of a given market was lower, any significant trend would result in a sizable win because the Turtles would have held more contracts of that lower volatility commodity.

VOLATILITY - THE MEANING OF N

The Turtles used a concept called "N" to represent the underlying volatility of a particular market. N is the 20-period EMA of the True Range (TR), which is now known as the Average True Range (ATR). Conceptually, N represents the average range in price movement that a particular market makes in a single period, accounting for opening gaps. N was measured in the same points as the underlying contract.

The True Range is computed as:

TR - Max(H - L, H - PPC, PPC - L)

• H = Current High
• L = Current Low
• PPC = Previous Period's Close

Then N is computed as:

N = (19 * PPN + TR) / 20

• PPN = Previous Period's N
• TR = Current Period's True Range

Note: Since this formula requires a previous period's N value, you must start with a 20-period simple average of the True Range for the initial calculation.

DOLLAR VOLATILITY ADJUSTMENT

The first step in determining the position size was to determine the dollar volatility represented by the underlying market's price volatility (defined by its N).

Dollar Volatility (DV), also known as Market Dollar Volatility, is computed as:

DV = N * DPP

• DPP = Dollars Per Point

VOLATILITY ADJUSTED POSITION UNITS

The Turtles built positions in pieces that they called Units, which were sized so that 1 N represented 1% of the account equity

A Unit (U) for a given market or commodity can be calculated using the following formula:

U = AV / DV

• AV = 1% of Account Value
• DV = is Dollar Volatility

MONEY MANAGEMENT

The initial risk allocation for all trades was 2%. However, aggressive pyramiding of more and more units had a down side. If no big trend materialized, then those little losses from false breakouts would eat away even faster at the Turtles' limited capital.

How did Eckhardt teach the Turtles to handle losing streaks and protect capital? They cut back their unit sizes dramatically. When markets turned around, this preventive behavior of reducing units increased the likelihood of a quick recovery, getting back to making big money again.

The rules were simple. For every 10 percent in draw-down in their account, Turtles cut their trading unit risk by 20 percent. This of course applies for bigger numbers: the unit risk would be decreased by 80% with a 40% draw-down.

ENTRY STRATEGY

The Turtles learned two breakout variants or "systems". System One (S1) used a 20-period price breakout for entry. However, the entry was filtered by a rule that was designed to increase the odds of catching a big trend, which states that a trading signal should be ignored if the last signal was profitable.

But this filter rule had a built-in problem. What if the Turtles skipped the entry breakout and that skipped breakout was the beginning of a huge and profitable trend that roared up or down? Not good to be on the sideline with a market taking off.

If the Turtles skipped a S1 20-period breakout and the market kept trending, they could and would get back in at the System Two (S2) 55-period breakout. This fail-safe S2 breakout was how the Turtles kept from missing big trends that were filtered out.

The entry strategy using System One (S1) is as follows:

• Buy a 20-period breakouts if last S1 signal was a loss;
• Short a 20-period breakouts if last S1 signal was a loss.

The entry strategy using System Two (S2) is as follows:

• Buy a 55-period breakout if we are not in the market, i.e. S1 trade was not taken.
• Short a 55-period breakout if we are not in the market, i.e. S1 trade was not taken.

The Turtles calculated the stop-loss for all trades using the Average True Range (ATR) of the last 30 periods, a value which they called N. Initial stop-loss was always 2 * ATR(30), or in their words, two volatility units. Additionally, the Turtles would add profits back into winning trades to maximize their winnings, commonly known as pyramiding. They could pyramid a maximum of 4 trades separated from each other by 1/2 volatility unit.

EXIT STRATEGY

The Turtles learned to exit their trades using breakouts in the opposite direction, which allowed them to ride very long trends.

The exit strategy using System One is as follows:

• Close long positions if/when the price touches 10-period low
• Close short positions if/when the price touches 10-period high

The exit strategy using System Two is as follows:

• Exit long positions if/when the price touches a 20-period low
• Close shorts positions if/when the price touches a 20-period high

OTHER CONSIDERATIONS

• Don't get too fixated to the 20,10 (S1) and 55,20 (S2) parameters
• The S1_TurtleTrendPeriods must always be higher than S1_TurtleStopPeriods
• The S2TurtleTrendPeriods must always be higher than S2_TurtleStopPeriods

PARAMETERS

The Turtle System Indicator has many configurable parameters. This allows for all aspects of the indicator to be changed for the user’s preferences. By default, the indicator is designed to work without any changes by the user. The parameters are divided into the following categories:

• Yancy Indicator Parameters
• Turtle Basic Parameters
• Turtle Period Parameters
• Turtle Strictness Parameters
• Turtle S1 Display Parameters
• Turtle S1 Size Parameters
• Turtle S1 Color Parameters
• Turtle S2 Display Parameters
• Turtle S2 Size Parameters
• Turtle S2 Color Parameters
• ATR Parameters
• Message Parameters
• Quite Time Parameters
• Message Info Parameters
• Debug Parameters

Yancy Indicator Parameters

These parameters control the overall functionality of the indicator. More specifically, it controls how the Turtle System Indicator is used within the trading terminal. The parameters in this section are:

IndicatorName – Default: Turtle System Indicator

This is the indicator name that is displayed in the chart data window. Changing this value does not impact the indicator’s calculations.

IndicatorOffset – Default: 0

The indicator calculations are made on the current data bar by default. This value can change the default and force calculations to be made based on previous bars. It is recommend to leave this parameter set to the default value.

Turtle Basic Parameters

The turtle basic parameters control how the indicator is calculated and used. Parameters in this section are:

UseWingPatterns – Default: false

Other YFX indicators can use data in the Turtle System Indicator. This functionality can be enabled by setting this parameter to ‘true’. By default, the integration is disabled.

UseTurtleSystem1 – Default: true

If true, then use the turtle trading system 1 as defined by the original turtles. This is the primary turtle system and parameters.

UseTurtleSystem2 – Default: false

If true, then use the turtle trading system 2 as defined by the original turtles. This was considered the fail-safe system.

Turtle Period Parameters

The turtle period parameters set the basic parameters for both turtle trading systems, S1 and S2. Parameters in this section are:

S1_TurtleTrendPeriods – Default: 20

Number of periods to use in calculating trend line values for System 1 (S1). The S1 trend periods must be larger than the S1 stop periods.

S1_TurtleStopPeriods– Default: 10

Number of periods to use in calculating stop trend lines for System 1 (S1). The S1 stop periods must be less than the S1 trend periods.

S2_TurtleTrendPeriods– Default: 55

Number of periods to use in calculating trend line values for System 2 (S2). The S2 trend periods must be larger than the S2 stop periods.

S2_TurtleStopPeriods– Default: 20

Number of periods to use in calculating stop trend lines for System 2 (S2). The S2 stop periods must be less than the respective trend periods.

Turtle Strictness Parameters

The turtle strictness parameters control how closely the turtle trading rules are interpreted. Parameters in this section are:

UseTurtleStrictTrendRules– Default: false

Apply strict rules like the original Turtles. Using strict rules for defining a trend means that the trend will be considered changed when a high price breaches the line. Loose rules define the breach as the closing price breaching the trend line.

UseTurtleStrictEntryRules– Default: false

Apply strict entry rules like original Turtles. This will impact how BUY/SELL decisions are made. In strict case, the high/low price is used to determine a trend breach. In loose mode, the closing price is used to determine a breach.

UseTurtleStrictExitRules– Default: false

Apply strict exit rules like the original Turtles. This will cause exits to be made when high/low breaks the respective trend line, as opposed to waiting for a close price to breach trend line. The loose mode uses the closing price approach.

UseTurtleStrictStopRules– Default: false

Apply strict stop-loss like the original turtles. Using a strict stop approach, a trade will exit if the high/low price breaches the stop line on the respective trend. The loose approach will only consider the closing price breaching the trend stop line.

IgnoreTurtleEntryPrice– Default: false

Do not worry about the trade entry price when deciding to exit a trade. Normally, only the closing price breach of a trend line is used to exit a trade. If the entry price is considered then a check is made to ensure that exit is made before the P/L turns negative.

Turtle S1 Display Parameters

The turtle S1 display parameters control how all the components of the S1 system are displayed. Parameters in this section are:

S1_DisplayUpperTrendLine– Default: true

Display the S1 upper trend line if true.

S1_DisplayLowerTrendLine– Default: true

Display the S1 lower trend line if true.

S1_DisplayShortStopLine– Default: true

Display the S1 short stop line if true. This is the dotted line just under the upper trend line.

S1_DisplayLongStopLine– Default: true

Display the S1 long stop line if true. This is the dotted line just above the lower trend line.

S1_DisplayBullishTrendChange– Default: true

Display the S1 bullish trend change marker if true. This is the marker that will be displayed once the uptrend begins.

S1_DisplayBearishTrendChange– Default: true

Display the S1 bearish trend change marker if true. This is the marker that will be displayed once the down trend begins.

S1_DisplayBuyBreakout– Default: true

Display the S1 buy breakout marker if true.

S1_DisplaySellBreakout– Default: true

Display the S1 sell breakout marker if true.

S1_DisplayExitLong– Default: true

Display the S1 long exit markers if true.

S1_DisplayExitShort– Default: true

Display the S1 short exit markers if true.

S1_DisplaySignals– Default: true

Display S1 BUY/SELL signals if true.

S1_PipOffsetDisplay– Default: true

Number of pips to use as offset when displaying S1 signal markers.

Turtle S1 Size Parameters

The turtle S1 size parameters control the size of chart objects used to display all the components of the S1. Parameters in this section are:

S1_WidthTrendLine – Default: 3

Width of S1 upper/lower trend lines.

S1_WidthStopLine – Default: 1

Width of line used to draw S1 long/stop lines.

S1_WidthTrendChange – Default: 2

Width of line used to draw S1 bullish/bearish trend change lines.

S1_WidthBreakout – Default: 3

Width of arrow used to draw S1 bullish/bearish breakouts (entries).

S1_WidthExit – Default: 3

Width of arrow used to draw S1 long/short exits.

S1_WidthTradeSignal – Default: 2

Size of S1 signal markers.

Turtle S1 Color Parameters

The turtle S1 color parameters manage the colors that are used to draw all the components of the S1 system on the chart. Parameters in this section are:

S1_ColorUpperTrendLine – Default: FireBrick

Color in which to draw S1 lower trend line.

S1_ColorLowerTrendLine – Default: SeaGreen

Color in which to draw S1 upper trend line.

S1_ColorShortStopLine – Default: DarkSlateGray

Color in which to draw S1 short stop line.

S1_ColorLongStopLine – Default: DarkSlateGray

Color in which to draw S1 long stop line.

S1_ColorBullishTrendChange – Default: SeaGreen

Color in which to draw S1 bullish trend change marker.

S1_ColorBearishTrendChange – Default: FireBrick

Color in which to draw S1 bearish trend change marker.

S1_ColorBuyBreakout – Default: SeaGreen

Color in which to draw S1 buy breakout markers.

S1_ColorSellBreakout – Default: FireBrick

Color in which to draw S1 sell breakout markers.

S1_ColorExitLong – Default: SeaGreen

Color in which to draw S1 long exit markers.

S1_ColorExitShort – Default: FireBrick

Color in which to draw S1 short exit markers.

S1_ColorBuy – Default: Aqua

Color for drawing S1 BUY signal.

S1_ColorSell – Default: Magenta

Color for drawing S1 SELL signal.

Turtle S2 Display Parameters

The turtle S2 display parameters control how all the components of the S2 system are displayed. Parameters in this section are:

S2_DisplayUpperTrendLine– Default: true

Display the S2 upper trend line if true.

S2_DisplayLowerTrendLine– Default: true

Display the S2 lower trend line if true.

S2_DisplayShortStopLine– Default: true

Display the S2 short stop line if true. This is the dotted line just under the upper trend line.

S2_DisplayLongStopLine– Default: true

Display the S2 long stop line if true. This is the dotted line just above the lower trend line.

S2_DisplayBullishTrendChange– Default: true

Display the S2 bullish trend change marker if true. This is the marker that will be displayed once the uptrend begins.

S2_DisplayBearishTrendChange– Default: true

Display the S2 bearish trend change marker if true. This is the marker that will be displayed once the down trend begins.

S2_DisplayBuyBreakout– Default: true

Display the S2 buy breakout marker if true.

S2_DisplaySellBreakout– Default: true

Display the S2 sell breakout marker if true.

S2_DisplayExitLong– Default: true

Display the S2 long exit markers if true.

S2_DisplayExitShort– Default: true

Display the S2 short exit markers if true.

S2_DisplaySignals– Default: true

Display S2 BUY/SELL signals if true.

S2_PipOffsetDisplay– Default: true

Number of pips to use as offset when displaying S2 signal markers.

Turtle S2 Size Parameters

The turtle S2 size parameters control the size of chart objects used to display all the components of the S2. Parameters in this section are:

S2_WidthTrendLine – Default: 3

Width of S2 upper/lower trend lines.

S2_WidthStopLine – Default: 1

Width of line used to draw S2 long/stop lines.

S2_WidthTrendChange – Default: 2

Width of line used to draw S2 bullish/bearish trend change lines.

S2_WidthBreakout – Default: 3

Width of arrow used to draw S2 bullish/bearish breakouts (entries).

S2_WidthExit – Default: 3

Width of arrow used to draw S2 long/short exits.

S2_WidthTradeSignal – Default: 2

Size of S2 signal markers.

Turtle S2 Color Parameters

The turtle S2 color parameters manage the colors that are used to draw all the components of the S2 system on the chart. Parameters in this section are:

S2_ColorUpperTrendLine – Default: FireBrick

Color in which to draw S2 lower trend line.

S2_ColorLowerTrendLine – Default: SeaGreen

Color in which to draw S2 upper trend line.

S2_ColorShortStopLine – Default: DarkSlateGray

Color in which to draw S2 short stop line.

S2_ColorLongStopLine – Default: DarkSlateGray

Color in which to draw S2 long stop line.

S2_ColorBullishTrendChange – Default: SeaGreen

Color in which to draw S2 bullish trend change marker.

S2_ColorBearishTrendChange – Default: FireBrick

Color in which to draw S2 bearish trend change marker.

S2_ColorBuyBreakout – Default: SeaGreen

Color in which to draw S2 buy breakout markers.

S2_ColorSellBreakout – Default: FireBrick

Color in which to draw S2 sell breakout markers.

S2_ColorExitLong – Default: SeaGreen

Color in which to draw S2 long exit markers.

S2_ColorExitShort – Default: FireBrick

Color in which to draw S2 short exit markers.

S2_ColorBuy – Default: Aqua

Color for drawing S2 BUY signal.

S2_ColorSell – Default: Magenta

Color for drawing S2 SELL signal.

ATR Parameters

The ATR parameters are used to control how the ATR indicator is used by the Turtle System Indicator. Parameters in this section are:

UseATR_Module – Default: false

Use ATR indicator in analysis.

ATR_Periods – Default: 30

Periods to use in ATR calculation.

ATR_SignalLine – Default: 25

Signal line value for ATR.

ATR_Multiplier – Default: 2.75

Default multiplier to use for ATR.

ATR_UseHistoricalExtremes – Default: false

If true, keep track of historical min/max values for ATR. If false, then only the extremes for the ATR_Periods number of bars is tracked.

ATR_HistoricalMaximumPeriods – Default: 100

The maximum number of periods to use for historical purposes. Data in periods greater than the maximum periods will not be considered in calculations.

Message Parameters

The message parameters determine how the indicator notifications are conveyed to the user. There are several options and the user can select which ones to use at any time. Multiple options can be enabled simultaneously.

DoShowComments - Default: false

Messages can be displayed in the comment section on the chart. By default, this option is disabled. Users can enable the option by setting parameter to ‘true’.

DoShowAlerts - Default: false

Messages can be displayed in the alert pop-up window on the terminal. By default, this option is disabled. Users can enable the option by setting parameter to ‘true’.

DoMailMessages - Default: false

Messages can be emailed to users if this option is enabled. By default, the option is disabled but can be enabled by setting the parameter to ‘true’. It is important that the user ensures that the mail options are configured and working in the trading terminal.

DoPushNotifications - Default: false

Messages can be pushed to a user’s mobile phone application. This option is disabled by default but can be enabled by setting the parameter to ‘true’. It is important that push notifications be configured correctly in the user’s trading terminal and mobile application.

DoPrintJournal - Default: false

Messages can also be written in the terminal’s journal. These messages are disabled by default but can be enabled by setting the parameter to ‘true’.

DoPrintFile - Default: false

Messages can be written to an external file on disk in the ‘Files’ folder. By default, this option is disabled by default but can be enabled by setting the parameter to ‘true’.

DefaultMessageFileName - Default: YFX_Messages.log

If the print to file option is enabled, then message notifications are written to a file with this name in the ‘Files’ folder.

DoSoundMessage - Default: false

Sounds can be played when a notification occurs. By default, this option is disabled but can be enabled by setting the parameter to ‘true’.

DefaultSoundFileName - Default: expert.wav

If the sound message option is enabled, then this sound file is played when notifications are generated.

Quiet Time Parameters

The quiet time parameters control when notification messages are conveyed to the user. Parameters in this section specify a time period when all notifications are disable. Settings in this section override the message parameters and alert parameters. No notification will be sent during quiet time.

DoQuietTime - Default: false

The quiet time process can itself be enabled or disable. It is disabled by default and that means that all alert message notifications will be sent when they are generated. Quiet time can be enabled by setting this parameter to ‘true’.

QuietTimeStart - Default: 01:00

If quiet time is enabled, then this parameter sets the start time of the period. No alert message notifications will be sent after this time. This parameter is only used if quiet time is enabled. It is ignored if quiet time is disabled.

QuietTimeEnd - Default: 07:00

If quiet time is disabled, then this parameter sets the end time of the period. No alert message notifications will be sent before this time. The parameter is only used if quiet time is enabled. It is ignored if quiet time is disabled.

Message Info Parameters

The message info parameters are used to configure if internal statistics are maintained by the indicator. The information is generally not needed by the user. Thus, it is recommended to leave the options disabled.

EnableInfo - Default: false

This parameter allow the statistics to be maintained by the indicator. It is disable by default but can be enabled by setting its value to ‘true’. If enabled, then statistical information will be maintained internally. That information would then be conveyed to user when the indicator starts and stops.

Debug Parameters

Sometimes it may be necessary to debug the indicator. Debugging can be configured with the parameters in this section. Debugging would cause a great number of messages to be generated if enabled. It is highly recommended to leave debug disabled.

EnableDebug - Default: false

Debugging can be enabled or disabled. By default, it is disabled and no debugging information is generated. Debugging can be enabled by setting this parameter to ‘true’. It is highly recommended to leave this option disabled as the amount of debug logging can be huge and slow down the trading terminal.

DebugLevel - Default: DEBUG_LEVEL_NONE

The amount of debugging information can be configure. By default, no information is generated. This is a drop down list and the user can select any one of the values in the list.

UseDatedLogs - false

If debugging is enabled, the information is written to an external file. The name of the file can be coded to contain the date of the log file.