Scotch 777 6250 CPI 9-Track Magnetic Tape Reel 3M Data Storage

Scotch 777 6250 CPI 9-Track Magnetic Tape Reel 3M Data Storage

The Scotch 777 is a 9-track open-reel magnetic tape from 3M's Scotch data storage line, formatted at 6250 CPI (characters per inch) — the high-density standard used widely in mainframe and minicomputer environments. The reel consists of a white plastic housing with a clear protective cover, an orange-accented hub ring, and a black locking clip for secure mounting on compatible tape transports.

Specifications & What's Included

• Brand: Scotch (3M)
• Model: 777
• Recording density: 6250 CPI (Characters Per Inch)
• Track format: 9-Track
• Tape width: 1/2 inch (0.5")
• Reel type: Open reel (reel-to-reel)
• Housing: White plastic reel with clear cover and orange hub ring
• Locking clip: Black plastic transport clip, present and intact
• Tape: Appears wound and present on reel

Applications

9-track magnetic tape reels at 6250 CPI were the dominant data storage and interchange medium for mainframe and large minicomputer systems from the 1970s through the early 1990s. The 9-track format uses eight data bits plus one parity bit across the tape width, and the 6250 CPI density (also called PE/GCR phase-encoding) was the highest standardized density for this format, enabling more data per reel than the earlier 800 or 1600 CPI variants. These reels were used on tape drives from IBM, Hewlett-Packard, DEC, Unisys, Memorex, StorageTek, and similar manufacturers for batch job processing, offsite backup, and data interchange between sites and systems. Today, 9-track tape reels are still sought by archivists, data recovery services, and legacy system operators migrating old data sets off aging mainframe infrastructure, as well as by collectors preserving vintage computing history.