Pion’s Interstellar Drive

written by Matthew Reed

Pion Interstellar Drive advertisement

Pion advertisement from the February 1983 issue of 80 Micro

The Interstellar Drive, also known as Pion’s Interstellar Drive, was a solid state disk drive emulator that was sold by Pion, Inc.1 of Arlington (later Watertown), Massachusetts. It was introduced in 1982 for a base price of $1,095.00 for the 256K version.

The Interstellar Drive was an external 9″ by 8 1/2″ by 4″ unit with its own power supply. It was compatible with the TRS‑80 Model III and Model 4 and included drivers for the TRSDOS and LDOS disk operating systems. By using different host interfaces, the Interstellar Drive was compatible with a number of computers, including the Apple II and the IBM PC.

No moving parts

Much like a modern solid state drive, the Interstellar Drive had no moving parts. It provided non-volatile data storage at speeds far greater than a hard drive (then commonly known as a Winchester drive) or a floppy drive. Advertisements described the Interstellar Drive as providing “five to fifty times faster performance than floppy disks and Winchester drives.”

Most modern solid-state drives use flash memory for non-volatile storage. The Interstellar Drive didn’t use flash memory, which has only just been invented and wouldn’t become common for a decade. It also didn’t use bubble memory, another contemporary type of non-volatile storage. Instead, it used the same dynamic memory that was being used in computers to provide very fast data access.

Because the Interstellar Drive was a separate unit, its power supply could remain turned on even when the computer it was connected to was turned off. This was important because dynamic memory requires power to keep its data. To guard against data loss, the Interstellar Drive included a battery backup. The battery could preserve the memory contents for up to thirty minutes without power.

Expansion

The base $1,095.00 version of the Interstellar Drive came with 256K of memory. Additional 256K add-ons cost $595.00. A fully expanded Interstellar Drive supported 1 megabyte (and would have cost $2,880.002).

These high prices relegated solid state drives such as the Interstellar Drive to niche applications where performance was very important. Pion Inc. described the Interstellar Drive as being “designed with second-generation high-density 64K DRAM technology to provide fast mass storage that speeds up any scientific, educational, or business program requiring disk access.”


  1. Some sources identify Axlon as the creator of the Interstellar Drive, but this is incorrect. Axlon did sell the Ramdisk 320, a very similar device for the Apple II. 
  2. That $2,880.00 price for 1 megabyte, adjusted for inflation, would be around $6,800.00 today. You can easily buy a 16 gigabyte memory card (which is 16,000 times larger) for less than $10.00 today. 
Categories: Hardware

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