Use PC's parallel port to plug in an extra disk drive


September 14, 1992|By MICHAEL J. HIMOWITZ | MICHAEL J. HIMOWITZ,(Michael J. Himowitz is a columnist for The Baltimore Sun.)

Adding a disk drive, tape backup unit or network adapter card to your PC can be a daunting job, particularly if you don't like the idea of taking your computer apart.

Even if you don't mind fooling with the hardware, you may be stymied if you have a small-footprint machine without an extra drive bay, or if you don't have an extra expansion slot for the controller board.

Fortunately, manufacturers have come up with simple alternatives -- external devices that connect to your printer's parallel port, the same port the printer uses. The nice part is that you don't have to give up your printer to use them.

While they often cost a bit more and run a little slower than drives that connect directly to your computer's innards, parallel port devices work well, are a snap to install and offer a major advantage: portability.

For example, if you have 10 PCs in your office, it's an expensive proposition to equip each one with a tape backup drive that may be used only once a week. But a single portable unit that plugs into the computer's parallel port can service all of them.

Laptop computer owners are prime candidates for parallel port drives. Many laptops are as svelte as they are because the manufacturer eliminated the floppy drive. If you want to install software on the computer's hard disk or transfer files, you have to connect the laptop to a desktop machine with a special cable and use special software -- a pain in the neck.

Even if your laptop does have a 3 1/2 -inch floppy, there's no way it can read data from 5 1/4 -inch disks -- the industry standard until a few years ago -- without passing the information through a desktop computer. A 5 1/4 -inch parallel port drive solves the problem neatly.

I'm surprised it took the industry so long to catch on to this trick. The parallel port, an internal circuit board with a connector that surfaces on the back of your computer, has been part of virtually every IBM-compatible sold since International Business Machines introduced the PC more than a decade ago.

Early on, IBM designated the parallel port as the printer connection. Printers are essentially one-way devices, so few manufacturers paid attention to other possibilities. But in- stead of using the flat, industry-standard Centronics plug on the computer end, IBM chose a more secure, 25-pin connector. There was a good reason for this.

Eventually, hardware makers realized that the parallel port was capable of full, high-speed, two-way communication with the computer's microprocessor. The exploding popularity of laptop computers, which have no room for additional expansion boards or storage devices, focused their attention on the parallel port as a path for getting information into and out of the machine.

But you don't have to be a laptop user to enjoy the benefits of this technology. For example, my kids have been bugging me for months to put a 3 1/2 -inch disk drive on their computer, an aging but capable mongrel PC that I assembled from various components over the years.

Like many machines of its vintage, their PC has two 5 1/4 -inch floppies and no place for a third. Even if there was room for another floppy, the computer's disk controller was designed to handle only two drives. I didn't want to give up one of the 5 1/4 -inch drives because I use them for duplicating disks.

Extracting a promise of good behavior and helpfulness in return for the hardware, I picked up a MicroSolutions BackPack 3 1/2 -inch drive. The company advertises that even a gorilla can install one of their drives. They're right.

I unplugged the printer from the computer, plugged in the cable from the BackPack and plugged the printer cable into the back of the floppy. The BackPack comes with its own power cord and adapter. That took about a minute. Then I ran the setup software, which installs BackPack's device driver, a memory-resident program that loads automatically when the computer starts. It lets the computer know that the BackPack is there and tells it how to access the drive. That took another minute. I restarted the computer and voila! Three floppy drives. The BackPack worked just fine. It coexisted well with my printer and, surprisingly, had no trouble with the Sound Source, another gadget that plugs into the parallel port and provides music, voice and sound effects for Walt Disney games. (I plugged the Sound Source in between the BackPack and the printer.)

There are many other parallel port devices on the market. Some are designed mainly for ease of installation, while others are designed for real portability.

MicroSolutions, for example, sells a line of parallel port floppies, hard drives and tape units in different shapes and sizes. For those who want mass storage, security and portability, the SysDos Puma removable cartridge drive can provide almost infinite capacity with its 44- or 88-megabyte cartridges.

If you need industrial-strength portable tape backup capability, consider the PT1 from Analog & Digital Peripherals, or Interpreter's TapeXchange. They're fast, expensive and come with carrying handles.

Whatever you buy, you'll always pay more than you would for an internal device, largely because an external drive has its own case and power supply. For example, an internal floppy drive costs about $75, while eternal drives that connects to a standard disk controller cost about $150 and parallel port floppies start at $200.

But if ease of installation and portability are important, or you're stuck with a computer that has no expansion room, they can be well worth the extra money.

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