Before storage vanished into silicon, it lived on film, glass, and metal. The moving parts and chemical coatings of these physical systems responded to specific engineering constraints and the demands of their respective moments. This week we use industrial CT to examine how five iconic formats worked, how they evolved, and why some still matter.

Day 1: Magnetic Tape

Magnetic tape appears outdated at first glance. It predates microprocessors, uses sequential access, and sits in silent racks. But it quietly stores much of the internet’s long-term memory. What explains its persistence?

Tape began in the 1950s with mainframes writing data to reels of acetate or PET film coated in iron oxide. In the 1980s, home computers like the VIC‑20 used audio cassettes to store data as modulated tones, slow at 50 bytes per second, but accessible and cheap. Its survival comes down to physics and economics. Tape is a PET strip coated in magnetic particles, written to by aligning domains with a read/write head. It’s not fast, but it is dense, efficient, and durable.

LTO, or Linear Tape‑Open, refines this idea. Cartridges use serpentine writing across dozens of tracks. LTO‑9 holds up to 45 terabytes compressed, with built-in error correction. Stored offline, these cartridges are immune to ransomware and accidental deletion.

A 2024 report shows LTO shipments hitting 176.5 exabytes compressed, a 15 percent rise. IEEE Spectrum notes that tape, once written, uses no power and retains data longer and more affordably than disk or flash. As IBM’s Mark Lantz put it, “The technology hasn’t been frozen in time. Quite the contrary.”

LTO remains the archival medium of choice for Amazon, Google, and CERN; it lasts up to 30 years under the right conditions. What may first look like legacy analogue tech turns out to be a refined archive engine designed for decades of reliable operation.

Give the CT scan of the LTO a spin in our Voyager window above. Internal reels, guide rollers, and reinforced structures reveal a tightly engineered storage system designed for precision and longevity. Tape, it turns out, is built to last.

Day 2: Floppy Disks and PocketZip

Floppy disks made personal computing portable and practical. The first commercial version (the truly floppy one), released in 1971, was 8 inches across and held just 80 kilobytes. It paved the way for more manageable sizes. By the late 1970s, the 5¼-inch disk became standard for early home and business computers, offering between 360 kilobytes and 1.2 megabytes of storage.

In the 1980s, a more durable format emerged: the 3½-inch floppy. Its rigid plastic shell (no longer physically floppy) and metal shutter protected the magnetic film inside, reducing dust contamination and physical damage. At 1.44 megabytes, it could store documents, program files, or even entire operating systems. These disks became a defining storage format for the personal computing era, remaining in common use into the early 2000s. Even today, the floppy icon still represents the Save function on many programs.

Iomega’s Zip and PocketZip formats attempted to extend this logic. The original Zip disk reached 750 megabytes by the end of its run. PocketZip, launched in 1999, packed 40 megabytes into a cartridge roughly the size of a matchbook. Its performance was impressive for the time, but the format suffered from alignment issues and media wear. The rapid rise of USB flash drives and solid-state storage soon rendered it obsolete.

In the scan of the 3.5-inch floppy, we see the dense, layered magnetic disk enclosed in its rigid plastic shell. The sliding metal shutter, which protects the media surface, is reinforced and spring-loaded. Also note the fine pitch of the read-write aperture and the minimal clearance between moving parts: tolerances that allowed reliable operation despite the format’s physical simplicity.

Day 3: ROM

Before optical discs and downloadable software, ROM cartridges were the primary medium for consumer electronics. Popularized by consoles like the Atari 2600 and Nintendo Entertainment System (NES), these plastic modules held pre-programmed data on a silicon chip known as mask ROM. When inserted into a console, the system could execute software directly from the cartridge without the need to copy data into RAM.

Each cartridge housed a printed circuit board, a ROM chip, and a set of exposed edge connectors. These aligned with spring-loaded contacts in the console, forming a direct electrical path. Unlike magnetic or optical media, ROM chips had no moving parts. They offered fast load times, physical durability, and built-in copy protection. But manufacturing was expensive, and the memory was fixed at fabrication.

Many users remember blowing into the cartridge to fix loading issues. This ritual sought to remove dust from the contacts, but it was rarely effective and often counterproductive. Moisture from breath could corrode the gold or nickel-plated pins over time. The real issue was usually poor contact alignment or oxide buildup on the connector surfaces.

Though cartridges faded as storage expanded and costs fell, they remain in use today in embedded systems and industrial equipment, where durability and immutability still matter.

Our CT scan of a ROM cartridge shows the chip mounted directly to the PCB with clean solder joints and a rigid housing. The edge connector is precisely spaced, designed to maintain tight electrical contact even after thousands of insertions.

Day 4: Magneto-Optical Discs

Magneto‑Optical (MO) discs blend magnetic and optical storage principles in a single hybrid system. Commercialized in 1985, they offered erasable, high-reliability storage long before affordable writable CDs appeared. MO media was typically 5.25‑inch or 3.5‑inch cartridges. The smaller version appeared in 1991 with capacities from about 128 MB up to 1.3 GB.

MO writing uses a two-step process: a laser heats a magnetic film spot to its Curie point. A magnetic head on the opposite side then sets the domain orientation. Reading uses a lower‑power laser to detect changes in polarization caused by the Kerr effect. Time‑consuming though it was, verification after writing made it highly reliable and durable, with tens of millions of rewrite cycles possible.

Enterprise archives like legal, medical, or media libraries looked to MO disks as a durable alternative to tape or early optical media. The cartridges physically protected surfaces from dust and fingerprints, and the media could tolerate temperature and humidity variations better than early CDs.

Our scan shows a thick ferromagnetic recording layer enclosed in robust polycarbonate casing. The dual-side configuration leaves just enough room for both the laser window and precise magnetic write head spacing. The cartridge’s sturdy guide system ensures laser alignment and minimal contact pressure.

Stay tuned for Day 5: Hard Drives and Solid State