Even if you choose not to subscribe, you have data on-hand that will allow you to test the program. The major drawback when using a CD-ROM database is that you are limited in timeliness of updates. Typically you will receive an updated database on a quarterly basis. In addition, you are responsible for making adjustments for dividends and stock splits yourself as well as manually correcting incorrect data. With a download service, these functions are typically automated.
Historical data is imperative when backtesting trading systems.
Having historical data on a CD-ROM will save you from having to download several years of historical data, also saving time and money. If you are thinking of upgrading or switching from an existing technical analysis program, you may want to keep in mind those data formats that can be imported into the new program. Many programs have built-in data conversion utilities that will take data from one program and convert it for use in another. You can save yourself time and money if you are able to take existing data and import it into a new program. Being able to export data allows you to use your data in other programs such as financial planners and portfolio management software.