NOT LONG AFTER the IBM Personal Computer made its debut, adventurous programmers learned about a nifty but undocumented feature of the new computer's disk operating system.
Although the PC was designed to run one only program at a time, they found that they could write software that would disappear from view after it was loaded. If the user pressed the right combination of keys, the program would pop up over whatever the computer was currently doing. Another keystroke combination would send the program back into the woodwork.
The new programs were called TSRs, a compu-babble acronym that means "Terminate and Stay Resident."
One of the first and most popular of these was Sidekick, from Borland International, a utility that would pop up a text editor, calculator, appointment calendar and other goodies.
New graphical user environments such as Microsoft Windows, which can run multiple programs simultaneously, have diminished the attraction of TSRs. But the latest release of Sidekick shows there's still some life in the genre.
Sidekick 2.0 ($69.95) is slick and rich in features but steals only 39K of memory when it's tucked out of sight. You can run it as a TSR or as a stand-alone program. It also will run on a corporate network, giving users access to common appointment schedules and other files.
The new Sidekick includes a powerful and flexible appointment calendar, a notepad, a communications program, an address book and phone dialer, and four different calculators.
When you press the CONTROL and ALT keys (you can change this combination to avoid conflicts with other software), Sidekick pops up over your word processor, spreadsheet or database. Press the Escape key a couple of times and it disappears.
The program operates in text mode, which means you don't want to use it with graphics applications. Like many new programs, it displays the the Common User Interface, a series of pull-down menus you can access with a mouse or a combination of keys.
From the menus, you can access any of Sidekick's functions or stack them on your screen in resizable windows.
Sidekick's slickest feature is a world-class appointment calendar -- a hot item in the software business today.
One side of the screen displays calendars of this month and next month, while the other side displays a scrolling list of appointments for any day you choose. Just select a time slot and hit the ENTER key to open an appointment form.
Unlike some schedulers, which are limited to half-hour or 15-minute intervals, Sidekick lets you start and end an appointment at any time. You can attach brief notes or full documents to any appointment and call them up for viewing and printing.
Sidekick stores its calendar information in a format compatible with its high-end Paradox database software. With Sidekick's tools, you to reconcile two different calendars to resolve conflicts.
But Sidekick's calendar really shines in the printing. In fact, Sidekick can put you into the professional calendar business. You can output daily, weekly or monthly calendars in a variety of formats -- full page, half page or notebook size. The quality is outstanding, particularly if you have a laser printer.
Unfortunately, high resolution printing is agonizingly slow. Once most users get over the gee-whizz feeling of seeing their calendars professionally printed, they'll probably opt for much quicker standard text printouts.
Sidekick's address book uses clever text character graphics to emulate one of those desktop gadgets with a little tab that slides along the alphabet to help you find the name you want. It's easy to use and search. If you have a modem, you can quickly dial any number in the book.
The notepad is a mixed bag. You can work with nine documents simultaneously and cut and paste information between them. In fact, you can cut and paste information between any two Sidekick applications. The notepad includes a spelling checker and thesaurus, features found mainly in high-end word processors.
Unfortunately, the notepad's text editor is much too quirky in handling line endings, paragraphs and reformatting. It uses an old Wordstar convention that requires two carriage returns to signify the end of a paragraph.
This means that many imported documents -- including electronic mail from the communications program -- will wind up looking like one big block of text.
Don't expect too much in the way of formatting, either. Despite the beautiful array of typefaces and print styles available in the appointment calendar, the notepad gives you no way to change text attributes and only minimal control over indentations. It's a shame, because a few decent word processing features would have made Sidekick a real winner.