IBM 3480 family
| Company type | Data storage technology |
|---|---|
| Industry | Computer storage |
| Predecessor | None |
| Founded | 1984 |
| Founder | IBM |
| Headquarters | Armonk , United States |
| Products | Magnetic tape data storage drives and cartridges (3480, 3480 IDRC, 3490E) |
| Parent | IBM |
The 3480 format represents a magnetic tape data storage technology developed by IBM. This tape measures inch in width and is housed within a cartridge containing a single reel, while the take-up reel resides inside the tape drive unit.
Thanks to their rapid performance, dependability, robustness, and cost-effective media, 3480 tapes and drives continue to be sought after. A notable advantage is their interchangeability—tapes recorded on one drive are typically compatible with others, even when produced by different manufacturers.
Between 1984 and 2004, multiple companies manufactured tape drives compatible with the IBM 3480 product family, including IBM itself, Fujitsu, M4 Data, Overland Data, StorageTek, and Victor Data Systems (VDS). Additionally, various models were marketed under brands such as DEC, MP Tapes, Philips, Plasmon, Qualstar, Tandem, and Xcerta.
IBM grouped all tape drives from the 3480 and 3490E series under the umbrella of the 3480 Product Family.
Interfaces
Originally created for IBM System/370 mainframes, the early 3480 tape drives utilized a bus-and-tag interface. Subsequent versions incorporated support for ESCON and high-voltage SCSI interfaces. The adoption of SCSI allowed these drives to connect with personal computers, enabling data transfer between mainframe systems and PCs.
3480
Released in 1984, the IBM 3480 was pioneering as the first tape drive to employ magnetoresistive (MR) read heads along with chromium dioxide magnetic tape.
In contrast to earlier designs, the interblock gap on this format is too narrow for the drive to halt tape movement within it, necessitating a write buffer mechanism. When data transmission pauses during writing, the drive moves past the gap, reverses to a secure stopping point while buffering incoming data, then accelerates forward again to write the buffered block. This innovation removes the requirement for vacuum columns, allowing for a more compact drive structure.
The 3480 delivers a high throughput of 3 megabytes per second by simultaneously reading and writing linear data across 18 tracks—approximately per inch of tape. This track count doubled that of previous IBM technology which featured 9 tracks at per inch. The cartridge holds 200 megabytes on a compact tape cartridge compared to earlier reels that stored 140 megabytes on a diameter ( length) reel of tape. Both the 3480 and its successors operate as streaming drives.
While IBM produced versions with bus-and-tag interfaces, other manufacturers offered models equipped with SCSI interfaces.
3480 IDRC
In 1986, IBM launched an enhanced hardware-based compression feature called Improved Data Recording Capability (IDRC) for the 3480 tape drive. With IDRC enabled, a single tape can store up to 400 megabytes. This format is also referred to as the 3490 recording format.
The IDRC-equipped 3480 drive uses identical cartridges as the standard model and maintains compatibility by reading and writing standard 3480 tapes.
3490E
Introduced in 1991, the IBM 3490E tape drive incorporates a 36-track head capable of storing up to 800 megabytes per cartridge. When combined with IDRC compression, it can hold as much as 2400 megabytes on an extended-length tape. Victor Data Systems (VDS), the final producer of these 36-track drives, ended manufacturing in late 2004 following IBM’s discontinuation of supplying thin film tape heads for this format.
Multiple manufacturers offered 3490E drives featuring bus-and-tag, ESCON, or high-voltage SCSI interfaces with data transfer rates reaching up to 20MB/s.
Though sharing physical dimensions with the older 3480 cartridges, the 3490E tapes use longer media optimized for the increased track count. Some legacy 3480 drives are capable of recording onto these extended tapes.
Certain models of the 3490E series can read tapes created by standard 3480 drives; others can write tapes that remain readable by those older devices. However, many units within this series exclusively support reading and writing on tapes formatted with all 36 tracks.
| Format | Introduction Year | Capacity (MB) | Number of Tracks |
|---|---|---|---|
| 3480 | 1984 | 200 | 18 |
| 3480 IDRC | 1986 | 400 | 18 |
| 3490E | 1991 | 800 | 36 |
| 3490E IDRC | 1992 | 2400 | 36 |
Advancements Following the 3480
The IBM 3590 "Magstar" format succeeded the IBM 3480 magnetic tape system, delivering markedly enhanced data transfer speeds and storage densities, featuring tape heads that supported between 128 and 384 tracks. Subsequently, the Magstar was superseded by the IBM 3592 "Jaguar" format.
External links
ECMA Standards
- ECMA 120 - 12.7mm 18-track tape
- ECMA 152 - 12.7mm 18-track tape - Extended Format
- ECMA 196 - 12.7mm 36-track tape