DollarLink News -- February 28, 1997

Enhancements Added

Cure for S&P over 819.0 and for any other symbol

This month we discovered that whenever the S&P futures prices go over 819.0 it causes DollarLink to lose accuracy. (It can't keep track of the numbers to the right of the decimal place.)

In order to be able to process S&P futures prices higher than 819.0 correctly, AND to take care of similar problems for ANY other symbol that may experience a big run-up in the future, we have added a user-controlled procedure to DollarLink.

DollarLink will now subtract a user-input number (called an "offset") from an incoming price for any symbol and store the result as a two-byte number. To use this stored number, the two-byte number is converted back into a floating point number and the offset is added.

The file called REDUCE contains the offsets to use for any symbol you want. It is a small text file and you can modify it with any text editor or word processor. DollarLink reads this file at startup. If it finds a line of the form

ABCD,NN.N

then DollarLink "knows" to offset all prices for the symbol ABCD by the amount NN.N.

If it finds a line of the form

AA_,NN.N

then it knows to offset all commodities with AA root part of the symbol name by the amount NN.N. For example, the line

SP_,500

tells DollarLink to offset all the SP futures contracts by subtracting 500.0 before storing the prices.

If the file REDUCE is not in the DollarLink directory, then DollarLink works as before this upgrade.

We supply this REDUCE file with the updates and it contains two lines

SP_,500
WP_,500

to take care of the S&P futures (day and night sessions)

You can easily add other symbols. For example,

$COMPQ,700.0

Adjusting historical data

After you upgrade, one step remains. The upgrade will affect all historical Using the REDUCE approach to keep the accuracy of a symbol involves one additional step: if you want to see historical data for that symbol prior to the time you started using REDUCE, you will have to modify the data because when DollarLink uses the data for display or numerical computations, it will add the offset amount and therefore old data will be too big (by the offset amount).

We have modified our SPLIT utility for this purpose. (You can also run SPLIT from inside DollarLink: place the cursor in text mode over the target symbol and press Del, and then 5. DollarLink will prompt you from there.)

For example, if you have decided to use the REDUCE solution with the line

SP_,500

then run the SPLIT utility from the DollarLink directory:

SPLIT SP_ -500 date1 date2

This tells the utility to subtract 500.0 from all SP futures contracts in all the historical files between dates date1 and date2.

[If you enter

SPLIT SP_ -500 0 0

then ALL the files that contain SP futures contract data will be adjusted.]

Another example:

Assuming you added the above $COMPQ,700 line to the REDUCE file, to adjust all the $COMPQ data run

SPLIT $COMPQ -700 date1 date2

After the SPLIT utility is done, it leaves the original files with B being the last letter of the file extension. (In other words, for example, the pre-SPLIT file 02-21-97.CLS will be now called 02-21-97.CLB and the SPLIT-adjusted file will be called 02-21-97.CLS.) After a few days of verification, you should delete all these historical files that end with a "B" from the disk because they take up room. To do that, from the DollarLink directory execute the following 5 commands:

del cls\*.clb [enter]
del 05m\*.05b [enter]
del 15m\*.15b [enter]
del 30m\*.30b [enter]
del 60m\*.60b [enter]

Back up your historical data before running SPLIT. Simply copy all your historical data to some temporary directory on your hard disk. We have included a batch file that you can use to back up all historical data to a directory called TMPDATA . To use it, from the DollarLink directory execute the command

BACKDATA TMPDATA [enter]

Again, after a few days of verification, you can delete all these back-up files with the command

del \TMPDATA [enter]

The PC will ask you Are you sure? Say yes.

To use REDUCE, you can request an update from us. All updates are free to currently active customers.

Active customers include all renters, all those on a six-month lease, all purchasers within the last 12 months, or purchasers who have paid the $300 support fee within the last 12 months. Contact us if you wish to check or change your status.

Go to top | Go To STS page | About Timing Laboratory | Go To DollarWin page