Q: There are many files in Windows that sure sound mysterious. Could you please define "pif" and "cab" files?

A: There is a lot of excitement about the new version of Windows, due out next month. Looking back in time, there was also a buzz when Microsoft produced Windows 3.1. When that was released, the company tried to have it work with older software that ran under DOS.

There were many tricks to make DOS programs work with Windows. One method was to use special programs called program information files. When you ran a DOS program, it would automatically look for the related ".pif" file. This little program might alter the memory so the DOS program could run.

The next upgrade was from Windows 3.1 to Windows 95. When Windows 95 was initially released, the company gave you so many floppy disks that you needed a wheelbarrow to get out of the store. One way to reduce the number of floppies was to compress the data. Cabinet files (.cab) were introduced as a way to organize this installation and to make the files take up less space.

Thank goodness CDs got popular.

Q: Should I get RDRAM or SDRAM?

A: SDRAM stands for "synchronous dynamic random access memory." It is designed to synchronize the memory with the microprocessor's clock speed, allowing for speedier processing. RDRAM stands for "rambus dynamic random access memory," a system developed by Rambus Inc. of Mountain View, Calif., to make things move faster by working with the motherboard as well as the chipset.

RDRAM, which can be expensive, is aimed at computers with extremely fast motherboards with powerful chipsets such as the Intel 820. People at home trying to play games and manipulate images from their digital cameras are demanding fast memory from their personal computers.

Years ago, machines with the fastest memory would usually be setting on corporate desks. Home users would always have the hand-me-downs. Today, however, things have changed--business users really don't need "screamin' " machines to produce an invoice, write a memo or connect to a network.

Many vendors will offer both RDRAM and SDRAM.

Q: I've got my cookie acceptance option turned off on my Web browser. Some sites I visit ask me nine or 10 times to set a cookie. It is driving me crazy.

A: The Internet faces a dilemma--Web surfers want terrific sites for free, yet Web sites are under increasing pressure to show a revenue stream, especially to pay programmers who command some mighty high salaries.

One way to derive income from a Web site is to sell advertising. But advertisers would rather not pay to pitch Irish dancing shoes to football players; they want to know as much about the site's visitors as they can.

We now have companies such as DoubleClick and AdForce that work with Web sites to track visitors. One technique is to set a "cookie" on the hard drive of a person's machine. When this person visits another Web page, it is possible for one of these "tracker" companies to profile where this person has been.

If you don't want to accept cookies, you generally have to put up with the constant queries. One option, though, is to surf anonymously through software offered by sites such as Zero-Knowledge Systems, at www.zks.net.

John Gilroy of Item Inc. is heard on WAMU-FM radio's "The Computer Guys" at 1 p.m. on the first Tuesday of the month. Send your questions to him in care of The Washington Post, 1150 15th St. NW, Washington, D.C. 20071-5302 or via e-mail at jgilroy@iteminc.com.